Detailed Chapter Outline
3.1 The Microprocessor
3.1.1 The Central
Processing Unit
3.1.2 Microprocessor
Speed
3.1.3 Trends in Microprocessor
Technology
3.1.4 Microprocessor
Architecture
3.1.5 Microcontrollers
3.1.6 Microperipherals
3.2 Computer Memory
3.2.1 Storage Hierarchy
3.2.2 Primary Storage
3.2.3 Secondary Storage
3.3 Generations of Computer Hardware
3.3.1 First Generation
of Computers
3.3.2 Second Generation
of Computers
3.3.3 Third Generation
of Computers
3.3.4 Fourth Generation
of Computers
3.3.5 Massively Parallel
Computers
3.3.6 DNA Computers
3.4 Computer Hierarchy
3.4.1 Supercomputers
3.4.2 Mainframe computers
3.4.3 Minicomputers
3.4.4 Workstations
3.4.5 Microcomputers
3.4.6 Laptop or notebook
computers
3.4.7 Palmtops
3.4.8 Personal digital
assistant (PDA)
3.4.9 Computing devices
3.5 Input/Output Devices
3.5.1 Human Data Entry
Devices
3.5.2 Source Data
Automation Devices
3.5.3 Output Devices
3.5.4 Multifunction
Devices
3.6 Multimedia
The Problem With Hardware
Business Problem
The Federal Aviation Administration (FAA) has a huge
problem. The agency is trying to keep 30 ancient IBM 3083 mainframe
computers from suffering year 2000 failures. According to IBM, fewer
than 100 of those old mainframes are still in use. The 3083s, manufactured
in the early 1980s, have only the processing power of modern high-end desktop
personal computers.
The 3083s are used in 15 of the 20 FAA control centers.
The FAA’s five busiest centers – Fort Worth, Cleveland, Chicago, New York,
and Washington – use modern IBM mainframe computers. FAA centers
keep track of all aircraft in U.S. airspace. The 3083s take radar
information and translate it into visual display data, reporting an aircraft’s
location, identity, altitude, speed, and destination for air traffic controllers.
IBM maintains that businesses are foolish to continue
running applications, particularly mission-critical applications, on old
mainframes. In fact, IBM is pressuring the FAA to upgrade its mainframes
to newer systems. IBM says that it has neither the replacement parts
nor people with the skills necessary to make the repairs.
Potential Business Solution
Buying the hardware for a new system would not be
very expensive. IBM RS/6000 workstations probably have the processing
power to run the application. The larger costs would come from upgrading
to a new operating system. Analysts estimate those costs could run
from $6 million to $30 million for the entire system.
(Source: “IBM Wants FAA to Retire 3083s.” Computerworld,
January 19, 1998)
Question: What should the FAA do?
Question: Given that the main expense is software, not
hardware, why is the FAA “hanging on” to old mainframes?
Question: What implications would you draw for any type
of computer hardware (i.e., minicomputers, workstations, personal computers,
laptops, etc.)?
Overview
Computers have spread throughout organizations and
are used in every functional area. Organizations and their employees
use computers of every size and speed to accomplish their strategies and
do their jobs more effectively and efficiently.
THE MICROPROCESSOR (CENTRAL PROCESSING UNIT
OR CHIP)
As we have noted in Chapter One, computer based
information systems (CBIS) are composed of hardware, software, databases,
telecommunications, people, and procedures. These components are
organized to input, process, and output data and information. This
chapter focuses on the hardware component of a CBIS. Hardware refers
to the actual equipment used for the input, processing, output, and storage
activities of a computer system and consists of a central processing unit,
input devices, output devices, primary storage, secondary storage, and
communications devices (communications devices are covered in chapter 6.)
Many companies are placing the responsibility and
authority for purchasing hardware with users in the functional areas.
The management information systems group assists the users in these decisions
by acting as technical advisers. You have an excellent chance, sometime
in your career, of making hardware purchasing decisions. Therefore,
a basic understanding of computer hardware is necessary and will be helpful.
The Central Processing Unit
The central processing unit (CPU) is also referred
to as the microprocessor or the chip. Chips are composed of millions
of transistors embedded on a silicon wafer. Memory, logic, and control
are contained on a single chip.
The CPU is the center of all computer processing
activities, where all processing is controlled, all data are manipulated,
arithmetic computations are performed, and logical comparisons are made.
The CPU consists of the control unit, the arithmetic-logic unit (ALU),
and the registers.
Buses. Instructions and data move between computer subsystems and the processor via communications channels called buses. A bus is a shared data path that connects different parts of a computer system. Bus capacities are usually given by the number of bits they carry at one time (the most common personal computer bus is 32 bits).
Control Unit. The control unit reads
instructions and directs the other components of the computer system to
perform the functions required by the program. It interprets and
carries out instructions contained in computer programs, selecting program
statements from primary storage or memory, moving them to the instruction
registers in the control unit, and then carrying them out. It controls
input and output devices and data-transfer processes from and to memory.
The control unit does not actually change or create data; it merely directs
the data flow within the CPU. The control unit can process millions
of instructions per second, but only one instruction at a time.
The series of operations required to process a single
machine instruction is called a machine cycle. Each machine cycle
consists of the instruction cycle (steps 1 and 2 below), which sets up
circuitry to perform a required operation, and the execution cycle (steps
3 and 4 below), during which the operation is actually carried out (see
Figure 2). The time to perform the instruction cycle is called
the instruction time and the time to perform the execution cycle is called
the execution time.
Step 1: Fetch instruction: The control unit gets the instruction
to be executed from memory.
Step 2: Decode instruction: The control unit decodes the
instruction so the central processor can understand what is required, moves
necessary data from memory to the registers, and identifies the location
of the next instruction.
Step 3: Execute the instruction: The arithmetic-logic unit
performs what it is instructed to do, either an arithmetic computation
or a logical comparison.
Step 4: Store the results: The results are stored in registers
or memory.
When both cycles have been completed for one instruction,
they are performed for subsequent instructions. Pipelining allows
central processing units to speed up processing. With pipelining,
the CPU gets one instruction, decodes another, and executes a third simultaneously.
The Pentium processor uses two execution unit pipelines, giving the CPU
the ability to execute two instructions in a single machine cycle.
Arithmetic-Logic Unit. The arithmetic-logic unit (ALU) performs required arithmetic and comparison, or logic, operations. The ALU adds, subtracts, multiplies, divides, compares, and determines whether a number is positive, negative, or zero. Comparison operations determine whether a number is greater or less than another number, or if they are equal. All computer applications are achieved through these six simple operations. The ALU operations are performed sequentially, based on instructions from the control unit. For these operations to be performed, the data must first be moved from primary storage to the arithmetic registers in the ALU. Registers are specialized, high-speed memory areas for storing temporary results of ALU operations as well as for storing certain control information.
Microprocessor Speed
The speed of a chip depends on five things:
the machine cycle time, the clock speed, the word length, the data bus
width, and the design of the chip. The machine cycle time is measured
in fractions of a second. Cycle times range from milliseconds (one-thousandth
of a second) and microseconds (one-millionth of a second) for slower computers,
to nanoseconds (one-billionth of a second) and picoseconds (one-trillionth
of a second) for faster computers. Machine cycle time can also be
measured in terms of how many instructions are executed in one second.
This measure, called MIPS (millions of instructions per second), is used
to measure speed for computers of all sizes.
The clock, located within the control unit, is the
component that provides the timing for all processor operations.
The control unit follows predetermined internal instructions, called microcode.
Microcode consists of predefined, elementary circuits and logical operations
that the processor performs when it executes an instruction. The
control unit executes the microcode in accordance with the electronic cycle
or pulses of the CPU clock.
The beat frequency of the clock (measured in megahertz
[MHz] or millions of cycles per second) determines how many times per second
the processor performs operations. All things being equal, a processor
that uses a 400 MHz clock operates at twice the speed of one that uses
a 200 MHz clock. The number of microcode instructions needed to execute
a single program instruction (e.g., performing an arithmetic operation)
varies, so there is no definite, direct relationship between clock speed
measured in megahertz and processing speed measures such as MIPs.
The word length is the number of bits that can be
processed at one time by a chip. Chips are commonly labeled as 8-bit,
16-bit, and 32-bit devices. A 32-bit chip can process 32 bits of
data in a single cycle. The larger the word length, the faster the
chip speed and the greater the precision in calculations.
The width of the buses determines how much data
can be moved at one time. The wider the data bus (e.g., 32 bits),
the faster the chip. Matching the CPU to its buses can affect performance
significantly. In some personal computers, the CPU is capable of
handling 32 bits at a time, but the buses are only 16 bits wide.
In this case, the CPU must send and receive each 32-bit word in two 16-bit
chunks, one at a time. This process makes data transmission times
twice as long.
If word lengths and bus widths are the same, then the larger the word
length, the more powerful the computer. Computers with larger word
lengths can transfer more data in the same machine cycle. They can
also use the larger number of bits to address more memory locations.
The design of the CPU components also helps to determine
how fast the processor can operate. The size of the integrated circuit
transistors on a chip directly affects the speed at which a transistor
can switch from one state to another; all things being equal, the smaller
the transistor, the faster it can switch. Also, the more densely
packed the transistors, the shorter the distance electrons must travel;
the shorter the distance, the faster the chip.
All five factors (machine cycle time, clock speed,
word length, data bus width, and chip design) affect the processing speed
of the CPU. Therefore, it is difficult to compare the speed of different
processors. For this reason, Intel, which controls over 75 percent
of the processor market for personal computers, has created a measure of
relative performance for its processors, called the iCOMP Index.
This index reflects the approximate, relative performance of Intel microprocessors
on 32-bit applications. A higher iCOMP rating means a higher relative
performance of the microprocessor. Table 1 shows the iCOMP ratings
of current Intel microprocessors.
Table 1: iCOMP Rating of Intel Microprocessors
Processor
Clock Speed iCOMP 2.0
Pentium II
400 MHz
440
Pentium II
350 MHz
386
Pentium II
333 MHz
366
Pentium II
300 MHz
332
Pentium II
266 MHz
303
Pentium II
233 MHz
267
Pentium Pro (MMX)
233 MHz
203
(Source: www.intel.com)
Trends in Microprocessor Technology
Table 3 shows the evolution of the microprocessor from the introduction of the 4004 in 1971 to today’s Pentium II and P6 microprocessors. Over time, microprocessors have become dramatically faster, more complex, and more dense, with increasing numbers of transistors embedded in the silicon wafer.
Table 3: Evolution of Microprocessors
Chip
Introduction Clock
Bus Number of
Addressable
Date
Speed
Width Transistors
Memory
4004
11/71 108 KHz
4 bits 2,300
640 bytes
8008
4/72 108 KHz
8 bits 3,500
16 Kbytes
8080
4/74 2 MHz
8 bits 6,000
64 Kbytes
8086
6/78 5-10 MHz
16 bits 29,000
1 Mbyte
80286
2/82 8-12 MHz
16 bits 134,000
16 Mbytes
80386 DX
10/85 16-33 MHz
32 bits 275,000
4 Gbytes
80386 SX
6/88 16-20 MHz
16 bits 275,000
4 Gbytes
80486 DX
4/89 25-50 MHz
32 bits 1.2 M
4 Gbytes
80486 SX
4/91 16-33 MHz
32 bits 1.185 M
4 Gbytes
80586 (Pentium) 3/93
60-166 MHz
32 bits 3.1 M
4 Gbytes
Pentium Pro
3/95 150-200 MHz
32 bits 5.5 M
4 Gbytes
Pentium II
1996 233-300 MHz
32 bits 5.5 M
4 Gbytes
80686
1997 up to 400 MHz
32 bits 7.5 M
4 Gbytes
Merced (P7) 1998
up to 500 MHz 64 bits
9 M
16 Gbytes
80886
2000 over 1000 MHz (estimated)
Source: www.intel.com
In 1970, the distance between transistors (line width)
was about 12 microns (12 millionths of a meter), or about one-tenth the
width of a single human hair. By 1990, the line width had decreased
to about 0.8 microns. The latest generation of chip has 7.5 million
transistors embedded on the silicon wafer, with the distances between transistors
decreasing to 0.3 microns. Recently however, scientists at the University
of Texas at Austin have produced an experimental circuit with distances
between circuit lines of just 0.08 microns. (see Figure 3)
The Merced chip (or P7), being jointly developed
by HP and Intel, will be in production in 1999. The line width on
this chip will be .18 microns, its clock speed is predicted to be over
500 MHz, and it is expected to contain over 50 million transistors. (see
Figure 4)
Improvements in processor manufacturing technology
have led to improved processor performance. Currently, processor
performance doubles about every 18 months, a trend that was predicted by
Gordon Moore, Intel Corporation cofounder. In April 1965, Moore predicted
that integrated circuit complexity would double approximately every two
years. Moore’s prediction has proven to be so accurate that it is
now known as Moore’s Law. Currently, physicists see no reason why
this trend cannot continue for several more years. (see Figure 5)
As transistors are packed closer together and the
physical limits of silicon are approached, scientists are developing new
technologies that increase the processing power of chips. (See Figure 5.3,
Turban 1e). Note: extend figure to include Pentium II, P6, and Merced
chips with information from Table 3). Chips are now being manufactured
from gallium arsenide (GaAs), a semiconductor material much faster
than silicon because electrons can move through GaAs five times faster
than they can move through silicon. Also, GaAs chips require less
power than silicon chips, but are more difficult to produce, resulting
in higher prices. GaAs chips are now being used in cellular telephones,
cable TV equipment, and digital TV.
Silicon germanium (SiGe) is a new material used
in making chips that results in increased speed, reduced electronic noise,
reduced expense, and reduced power requirements. SiGe technology
is promising for reducing the cost of consumer products (e.g., cellular
telephones and direct broadcast satellite entertainment services), improving
business applications (e.g., telephone network transmission), and helping
make possible new applications (e.g., collision-avoidance automobile radar).
Microprocessor Architecture
The arrangement of components and their interactions
is called an architecture. Computer architectures include the instruction
set and the number of the processors, the structure of the internal buses,
the use of caches, and the types and arrangements of input/output (I/O)
device interfaces.
Every processor comes with a unique set of operational
codes or commands that represent the computer’s instruction set.
Today, two instruction set strategies, complex instruction set computing
(CISC) and reduced instruction set computing (RISC), dominate the processor
instruction sets of computer architectures. These two strategies
differ by the number of operations available and how and when instructions
are moved into memory.
Complex instruction set computing.
A CISC processor contains more than 200 unique coded commands, one for
virtually every type of operation. Therefore, inexpensive hardware
can replace expensive software, reducing the cost of developing software.
The penalty for this ease of programming is that CISC processor-based computers
have increased complexity and slower performance. In spite of these
drawbacks, most computers still use CISC processors.
Reduced instruction set computing.
The other, more recent, approach is RISC processors, which eliminate many
of the little-used codes found in the complex instruction set. Underlying
RISC design is the claim that a very small subset of instructions accounts
for a very large percentage of all instructions executed. The instruction
set, therefore, should be designed around a few simple “hard-wired” instructions
that can be executed very quickly. The rest of the needed instructions
can be created in software. These instructions will be somewhat slower
than built-in instructions, but they are typically used so seldom that
it does not matter. RISC processor-based computers (e.g., workstations)
are significantly faster than CISC processors.
The PowerPC chip is a RISC processor created by
Motorola under agreement with IBM and Apple Computer. Digital Equipment’s
Alpha chip and Sun Microsystems’ Sparc chip are also examples of RISC processors.
Intel has incorporated MMX (multimedia extension)
technology in its Pentium microprocessors. MMX technology improves
video, audio, graphical, and image processing, encryption, and input/output
processing, all of which are used in modern office software suites and
advanced business media, communications, and the Internet.
It is also possible to reduce the number of instructions
in a chip by making each instruction very long. This approach, called
the very long instruction word (VLIW), is being developed by Intel and
Hewlett-Packard.
Microcontrollers
Microcontrollers are integrated circuit chips that
are used in embedded applications such as automobile engine control, timing
in microwave ovens, and in medical products including hearing aids, fetal
monitors, and pacemakers. Microcontrollers are also contained in
computer peripherals, such as laser printers and disk drives, and are becoming
increasingly important in telecommunications devices such as cellular phones.
In fact, microcontrollers are being used throughout
our automobiles. Mechanical components such as steering columns,
brakes, and throttle cables are being replaced by wires and computer chips.
The results are steer-by-wire, brake-by-wire, and throttle-by-wire systems.
In “by-wire” systems, the actions of the driver (turning the steering wheel
or pressing on the brake pedal) are detected by sensors and relayed to
computer chips. These chips then signal motors to turn the wheels
or activate the brakes.
The microcontrollers can do more than just relay
the driver’s intent – they can embellish that intent with intelligence.
Antilock braking systems were an early example. Current systems are
much more sophisticated. For example, new cruise controls do not
just maintain a set speed. They use radar to gauge the speed of a
slower-moving vehicle ahead and automatically slow your car to the same
speed until you decide to pass. Other sensors surround your car with
an early-warning system. Infrared detectors can spot the heat of
a car in your blind spot and sound an alarm as you begin to change lanes.
New radar sensors will see past a truck ahead – by bouncing a signal off
the pavement under the truck – to determine if it is safe for you to pass.
Microperipherals
Microperipherals, such as digital signal processors
(DSPs), are integrated circuit chips that perform the digital-to-analog
and analog-to-digital conversions used in audio, communications, and image
manipulation. Many new applications for image manipulation are emerging,
including:
consumer photography – new “smart sensors will automatically
correct exposure and allow images to be edited right on the camera;
computers – “eyeball” digital cameras will be built
into monitors for video mail or for verifying the user’s identity; keyboards
with built-in fingerprint scanners will substitute for passwords;
handheld devices – small digital cameras will become
common accessories for cellular telephones and personal digital assistants;
retailing – fingerprint and retinal scanners that
can instantly verify someone’s identity will be widely used by retail stores,
banks, and government agencies;
medicine – imaging chips may help blind people see
and will be commonly used in surgery;
automobiles – digital cameras will supplement rearview
mirrors, check tire pressure, and monitor occupants as part of advanced
safety systems.
COMPUTER MEMORY
Computers store data and information in the form
of 0’s and 1’s (i.e., binary digits or bits). For this reason, we
say that computers are digital. The storage capacity of computers
is usually measured in terms of bytes (eight bits).
Storage Hierarchy
As capacities have increased dramatically, a hierarchy
of terms is used to describe computer storage.
Kilo (abbreviated with the letter K) means one thousand,
so a kilobyte (KB) is approximately one thousand bytes. Actually,
a kilobyte is 1,024 bytes (210 bytes).
Mega (abbreviated with the letter M) means one million,
so a megabyte (MB) is approximately one million bytes. Actually,
a megabyte is 1,048,576 bytes (1024 x 1024 bytes). For example, if
you own a computer with 32 megabytes of RAM, then the random access memory
on your computer contains 33,554,432 bytes of storage.
Giga (abbreviated with the letter G) means one billion,
so a gigabyte (GB) is approximately one billion bytes. Actually,
a gigabyte is 1,073,741,824 bytes (1024 x 1024 x 1024 bytes). For
example, if you own a computer with 6.4 gigabytes of storage on the hard
drive, then your secondary storage device contains 6,871,947,674 bytes
of storage. Suppose that you are using a word processor with 12-point
font and normal spacing between lines. With approximately 15 words
per line, 22 lines per page, and 6 bytes per word, each page would contain
about 2000 bytes. Therefore, your 6.4 gigabyte hard drive would hold
a little over 3.4 million pages of text.
Tera (abbreviated with the letter T) means one trillion,
so a terabyte (TB) is approximately one trillion bytes. Actually,
a terabyte is 1,078,036,791,296 bytes (1024 x 1024 x 1024 x 1024 bytes).
Primary Storage
Primary storage, or main memory, has three main
functions. First, it stores all or part of the program being executed.
Second, it stores the operating system programs that manage the operation
of the computer. Third, it stores the data that are being used by
the program.
Primary storage in today’s microcomputers utilizes
integrated circuits, which are interconnected layers of etched semiconductor
materials forming electrical transistor memory units with “on-off” positions
that direct the electrical current passing through them. The “on-off”
states of the transistors are used to establish a binary 1 or 0 for storing
one binary digit, or bit. A sufficient number of bits to represent
specific characters – letters, numbers, and special symbols – is known
as a byte, usually 8 bits. Because a bit has only two states, 0 or
1, the 8 bits comprising a byte can represent any of 28, or 256, unique
characters. The character represented depends upon the bit combination
or coding scheme used. The two most commonly used coding schemes
are ASCII (American National Standard Code for Information Interchange)
and EBCDIC (Extended Binary Coded Decimal Interchange Code).
Another coding scheme is unicode. The
Unicode Worldwide Character Standard is a character coding system that
supports the interchange, processing, and display of the written texts
of the world’s languages. Unicode also supports classical and historical
texts in many languages.
There are four kinds of primary memory: register,
cache memory, random access memory (RAM), and read only memory (ROM).
Registers. Registers are part of the
CPU where instructions and results are stored for very short periods of
time. They are the fastest, smallest, and most expensive type of
memory.
Cache Memory. Many software programs
are larger than the internal, primary storage (RAM) available to store
them. To get around this limitation, some programs are divided into
smaller blocks, with each block loaded into RAM only when necessary.
However, depending on the program, continuously loading and unloading blocks
can slow down performance considerably, especially because secondary storage
is so much slower than RAM. As a compromise, most processors use
high-speed cache memory as temporary storage for the most often used blocks,
RAM to store the next most often used blocks, and secondary storage for
the least used blocks. Cache memory operates at a much higher speed
than conventional memory (i.e., RAM), because it reduces the number of
times the program has to fetch instructions and data from RAM and secondary
storage.
Random Access Memory (RAM). Primary
storage that may be read or written to is known as random-access memory
(RAM). RAM is the area in which the CPU stores the instructions and
data it is processing. The larger the memory area, the larger the
programs that can be stored and executed.
With newer computer operating system software, more
than one program may be operating at a time, each occupying a portion of
RAM. Most personal computers today need at least 16 to 32 megabytes
of RAM to process multimedia applications, which combine sound, graphics,
animation, and video.
The advantage of RAM is that it is very fast in
storing and retrieving any type of data, whether textual, graphical, sound,
or animation-based. Its disadvantages are that it is relatively expensive
and that it is dynamic or volatile. This volatility means that all
data and programs stored in RAM are lost when the power is turned off.
To lessen this potential loss of data, many of the newer application programs
perform periodic automatic “saves” of the data.
Read-Only Memory (ROM). Read-only memory
(ROM) is that portion of primary storage that cannot be changed or erased.
ROM is nonvolatile; that is, the program instructions are continually retained
within the ROM, whether power is supplied to the computer or not.
ROM is necessary to users who need to be able to restore a program or data
after the computer has been turned off or, as a safeguard, to prevent a
program or data from being changed. For example, the instructions
needed to start, or “boot,” a computer must not be lost when it is turned
off.
Programmable ROM (PROM) memory chips are used when
it is necessary to make changes for a particular client or configuration.
A PROM chip can be programmed once (and only once) by a customer, thereby
reducing the necessity of having to wait for the manufacturer to have a
production run for a customized chip. PROM chips are used where the
CPU’s data and instructions do not change, but the application is specialized
making the manufacture of a ROM chip too expensive. For example,
PROM chips are used to store the instructions for video games.
Erasable PROM (EPROM) chips can be programmed in
the field and can also be erased for reprogramming. EPROM chips are
usually used for device control, such as in robots, where the program may
have to be changed on a routine basis. An industrial robot, for example,
might perform repetitive operations in a steel mill, making a particular
piece of steel. When it is necessary for the robot to work on a different
piece of steel, the EPROM controlling the robot’s operation must be erased
and reprogrammed.
Secondary Storage
Secondary storage is separate from primary storage
and the CPU, but directly connected to them. Secondary storage stores
data in a format that is compatible with data stored in primary storage,
and provides the computer with vastly increased potential for storing and
processing large quantities of software and data for long periods.
Primary storage is fixed in size, (although it can be readily increased),
volatile, contained in memory chips, and very fast in storing and retrieving
data. On the other hand, secondary storage is not fixed in size and
is nonvolatile. Further, secondary storage can be on many different
forms of media that are less expensive than primary storage, but are relatively
slower than primary storage. Secondary storage media include magnetic
tape, magnetic disk, magnetic diskette, and optical.
Magnetic tape. Magnetic tape
is kept on a large reel or in a small cartridge or cassette. Today, cartridges
and cassettes are replacing reels because they are easier to use and access.
The principal advantages of magnetic tape are that it is very inexpensive,
relatively stable, long-lasting, and can store very large volumes of data.
Magnetic tape, which is reusable, is used most frequently for backup or
archival storage of data, systems backup and restoration, and off-site
data storage for disaster recovery in mainframe and server systems.
The main disadvantage of magnetic tape is its potentially
slow response time, because it offers only sequential access. That
is, data are stored continuously on a tape which must be searched sequentially
from the beginning to find the desired data. Also, the magnetic tape
itself is fragile and must be handled with care and the magnetic tape reels
are labor intensive to mount and dismount.
For mainframes and large servers, 0.5 inch cartridge
tape drives provide large data storage capacities and high data transfer
transfer rates. Cartridges currently can store over 30 gigabytes
of data and can exhibit data transfer speeds of up to 20 million bits per
second.
Storage productivity has been greatly enhanced by
the introduction of automated tape retrieval systems, which use robots
to retrieve and replace the tens of thousands of magnetic tape cartridges
used by mainframes and large servers. The cartridges are stored in
structures called silos. For example, StorageTek’s robotic cartridge
library system holds up to 6,000 tape cartridges in a silo that is eight
feet tall and twelve feet in diameter.
Magnetic tape is also useful for personal computer
and small server backup. A single tape can typically accommodate
a backup copy of most hard drives, a task that is difficult to accomplish
using floppy disks. The major tape formats used for personal computers
and small servers are 8 mm tapes, 4 mm tapes (also known as digital audio
tape or DAT), digital linear tape (DLT), and quarter-inch cartridges (QIC).
Magnetic disks. Magnetic disks
(called hard disks) access data faster than magnetic tape by assigning
specific address locations for data, so that users can go directly to the
address without having to go through intervening locations looking for
the right data to retrieve. Therefore, we say that magnetic disks
offer direct access to data. Most computers today rely on hard disks
for retrieving and storing large amounts of instructions and data in a
nonvolatile and rapid manner. The hard drives of modern microcomputers
can provide up to 20 gigabytes of data storage. (See Figure 6)
Hard drives keep getting smaller and providing more
storage. IBM recently introduced a hard drive weighing less than
an AA battery that can hold 340 megabytes of data. This hard drive
is used in car navigation systems to store maps and addresses, in handheld
computers to store schedules and telephone numbers, and in digital cameras
to provide storage for digitized photographs.
A hard disk drive is a stack of metal-coated platters
(usually permanently mounted) that rotate rapidly. Magnetic read-write
“heads”, attached to arms, hover over the platters. To locate an
address for storing or retrieving data, the head moves inward or outward
to the correct position, then waits for the correct location to spin by
underneath. Most hard-disk drives are housed in hermetically sealed
containers to avoid contamination.
Over time, magnetic disks and disk drives have gotten
smaller and simultaneously faster, denser, and less expensive. According
to Dataquest, the cost per megabyte of hard disk storage fell from $75
in 1982 to $0.45 today. As the cost per megabyte has fallen, the
number of megabytes per drive has increased. Therefore, the price
for a disk drive has remained relatively constant.
The speed of access to data on hard disk drives
is a function of the rotational speed of the disk and the speed of the
read/write heads. The read/write heads must position themselves,
and the disk pack must rotate until the proper information is located.
Advanced disk drives rotate at 7,200 revolutions per minute and have access
speeds of 1.5 to 10 milliseconds.
Magnetic disks provide storage for large amounts
of data and instructions that can be rapidly accessed. Their disadvantage
is that they are more expensive than magnetic tape and they are susceptible
to “disk crashes.” The read-write heads float just above the surface
of the platters, at a distance of only 0.25 micrometers (25 millionths
of a meter). For comparison, consider that the read-write heads float
above the platters at a distance smaller than a particle of smoke.
A disk crash occurs when the read-write heads come into contact with the
surface of the platters, thereby damaging both the heads and the disk surfaces.
Though rare, disk crashes usually result in catastrophic loss of data.
Another disadvantage of magnetic disks is that updating
information stored on a disk destroys the old information because the old
data on the disk is written over when changes are made. In contrast,
changes to data made on magnetic tape are made on a different reel of tape
so that the old version of the tape can be retained and recovered.
Removable disk drives were developed to accommodate
larger storage requirements generated by the increased multimedia content
of business and consumer software. Increased business travel also
created a need for reliable, portable data transfer media that could hold
larger amounts of data.
Removable disk drives are faster than removable
floppy disk drives because their disks are composed of compact, rigid platters
that can spin at a faster rate. The one gigabyte Iomega Jaz cartridge,
for example, spins at a rate fast enough for multimedia playback as well
as storage.
Hard drives in all computer systems are susceptible
to failures caused by temperature variance, head crashes, motor failure,
controller failure, and changing voltage conditions. In addition,
operating system malfunctions, viruses, and heavy input and output traffic
impact disk reliability. To improve reliability and protect the data
in their mass storage systems, companies are combining a large number of
small disk drives developed originally for microcomputers. These
devices are called Random Arrays of Inexpensive Disks (RAID).
Because data are stored across many drives, the overall impact on system
performance is lessened when one drive malfunctions. Also, multiple
drives provide multiple data paths, improving performance. Finally,
because of manufacturing efficiencies of small drives, the cost of RAID
devices is significantly lower than the cost of large disk drives of the
same capacity.
Disk mirroring (keeping an exact copy of one disk
on another) is the simplest way of protecting data, but it requires twice
the disk capacity and associated cost. Mirroring, known as RAID 1,
is used by many information-intensive industries such as banks and insurance
companies.
A disk controller controls the transfer of information
between the disk drives and the rest of the computer system. Most
personal computers today use one of two high-performance interface standards:
the Integrated Drive Electronics (IDE) interface or the Small Computer
Systems Interface (SCSI).
Hard disk drives featuring IDE interfaces are standard
in today’s personal computers because they offer good performance and are
inexpensive. A newer version of the IDE specification known as Enhanced
IDE (EIDE) supports more devices, such as CD-ROMs, tape drives, and optical
discs, and offers increased transfer rates.
Hard disk drives featuring small computer system
interfaces (SCSI) are generally found in servers and high-end workstations.
These interfaces are rapidly gaining acceptance in desktop computers.
SCSI drives are more expensive than IDE drives, but they can transfer data
at faster rates.
Magnetic Diskettes. To transport data
or instructions from one personal computer to another, developers
created the magnetic diskette, also called the “floppy disk.” The
floppy disk is a small, removable, flexible magnetic platter encased in
a plastic housing. Unlike the hard disk drive, the read-write head
of the floppy disk drive actually touches the surface of the disk.
As a result, the speed of the floppy drive is much slower, with an accompanying
reduction in data transfer rate. However, the diskettes themselves
are very inexpensive, thin enough to be shipped into books or mailed, and
able to store relatively large amounts of data.
The most common floppy disks today are the 3.5 inch
rigid case diskettes with a capacity of 1.44 MB. High-density, removable
floppy disk drives are faster than standard 1.44 MB floppy drives and use
disks with much higher capacities, ranging from 25 MB to more than 200
MB. For example, Iomega Corporation produces the 100 megabyte
Zip drive, and Syquest produces the 230 megabyte EZFlyer and 4.7 gigabyte
Quest models.
Optical storage devices. Optical storage
devices use lasers that write to and read from disks. These devices
have extremely high storage density. Typically, much more information
can be stored on an optical disk than on a comparably sized magnetic disk.
Because a highly focused laser beam is used to read or write information
encoded on an optical disk, the information can be highly condensed.
In addition, the amount of physical disk space needed to record an optical
bit is much smaller than that usually required by magnetic media.
Another advantage of optical storage is that the
medium itself is less susceptible to contamination or deterioration.
First, the recording surfaces (on both sides of the disk) are protected
by two plastic plates, which keep dust and dirt from contaminating the
surface. Second, only a laser beam of light comes in contact with
the recording surface, not a flying head; the head of an optical disk drive
comes no closer than 1 mm from the disk surface. Optical drives are also
less fragile, and the disks themselves may easily be loaded and removed.
Optical storage media do have disadvantages.
Optical disks are slower than magnetic disks, and optical disk drive mechanisms
are more expensive than magnetic drives.
Automated optical disc changers, known as optical
jukeboxes, typically hold several discs and contain one or more drives
to provide access to multi-volume libraries of data. Optical storage
is a reliable medium that falls between the less expensive, but slower
tape drive options and the more expensive, but faster magnetic disk drive
options.
Three common types of optical drive technologies
are CD-ROM, WORM, and rewritable optical. Compact disk read-only
memory (CD-ROM) disks have high capacity and low cost. CD-ROM technology
is very effective and efficient for mass producing many copies of large
amounts of information that does not need to be changed. For example,
encyclopedias, directories, and on-line databases use CD-ROM technology.
After a master disc has been produced, copies can
be manufactured very inexpensively. The unit cost is somewhat less
than $1.00 for quantities of 2,000 discs. Because of this inexpensive
duplication, CD-ROMs having capacities of 650 megabytes are ideal for publishing
large amounts of text, data, computer programs, or images in an electronically
readable form.
CD-ROM discs have almost completely replaced magnetic
tape and magnetic disks for the distribution of software and documentation
for personal computers and workstations. In addition, CD-ROM drives
are now becoming standard on new personal computer systems. Most
CD-ROM disc drives play audio and data discs interchangeably.
CD-ROMs are generally too expensive for unique,
one-of-a-kind applications. For these situations, “write once, read
many” (WORM) technology is more practical. WORM drives are useful
for archiving digitized documents. The storage capacity and access
time for WORMs are virtually the same as those with CD-ROMs.
Advances in CD-ROM technology include CD-Rewritable
and digital video discs (DVD). When information needs to be changed
or updated, and companies do not want to incur the expense of mastering
and producing a new CD-ROM, rewritable optical disks are needed.
Digital video disks offer the storage equivalent
of up to about eight CD-ROM discs. With advanced compression technologies,
one digital video disk will hold a 133-minute movie accompanied by a surround-sound
audio track.
The DVD standard specifies that players will be
able to read current CDs and CD-ROMs, as well as DVDs. Two sided
DVDs will be able to hold up to 17 gigabytes. Like CD-ROMs, DVDs
will be used to store music, movies, and multimedia packages. However,
DVD packages will be enhanced with features, that, for example, might offer
viewers a choice of camera angles or several different sound track languages.
Experts predict that in the near future, DVD technology will produce a
product that could hold more than 50 GB on a 1.2 millimeter thick platter,
the equivalent of a small library on a single disc.
Flash memory. Flash memory, a
type of nonvolatile memory, can be reprogrammed. It is either built into
a system or installed on a personal computer card (known as a flash card,
which has 40 or 80 megabytes). These cards consume less space and
less power than a disk drive, and are very important in small, hand-held
battery-powered devices such as portable telephones and digital cameras.
Figure 7 shows the relationships among primary and secondary storage devices
along the dimensions of cost, size, and speed.
GENERATIONS OF COMPUTER HARDWARE
Computer hardware has evolved through four stages,
or generations, of technology. Each generation has provided increased
processing power and storage capacity, while simultaneously exhibiting
decreases in costs. For example, the cost of performing 100,000 calculations
decreased from several dollars in the 1950s to less than $0.025 in the
1980s to about $.00004 in 1995. The advent of new technologies that
perform the processing functions has dictated the beginning of each successive
generation of computers.
First Generation of Computers
The first generation of computers (circa 1946-1956),
used vacuum tubes to store and process information. Vacuum tubes
consumed large amounts of power, generated much heat, and were short-lived.
First generation computers had limited memory and processing capability.
The size of main memory was about two kilobytes and the computer speed
was approximately ten thousand instructions per second. Rotating
magnetic drums were used for internal storage and punched cards for external
storage and data and program input. Running programs and printing
output were coordinated manually.
Second Generation of Computers
The second generation of computers (circa 1957-1963),
used transistors for storing and processing information. Transistors
consumed less power than vacuum tubes, produced less heat, and were cheaper,
more stable, and more reliable. For memory, these computers used
magnetic cores, composed of small, magnetic doughnuts that could be polarized
in one of two directions to represent one bit of data. These cores
were strung with wire to read and write data. This system had to
be assembled by hand, and was very expensive. These computers had
up to 32 kilobytes of RAM and speeds of up to 300 thousand instructions
per second. Second-generation computers, with increased processing
and storage capabilities, began to be more widely used for scientific and
business purposes.
Third Generation of Computers
Third-generation computers (circa 1964-1979), used
integrated circuits for storing and processing information. Integrated
circuits are made by printing numerous, small transistors on silicon chips.
These devices were called semiconductors. Computer memories expanded
to two megabytes of RAM and speeds increased to five MIPs. Third-generation
computers employed software that could be used by non-technical people,
thus enlarging the computer’s role in business.
Fourth Generation of Computers
Fourth-generation computers (circa 1980-present),
use very large scale integrated circuits to store and process information.
Computer memory has increased to over two gigabytes in large machines and
processing speeds can exceed 1000 MIPs. These computers are inexpensive
and are widely used in business and everyday life.
The first four generations of computer hardware
are based on the Von Neumann architecture, which processes information
sequentially, one instruction at a time. The fifth generation of
computers uses massively parallel processing to process multiple instructions
simultaneously.
Fifth Generation: Massively Parallel Computers
Normal desktop computers have a single processor.
However, some computers have more than one processor and can perform multiprocessing.
Coprocessing. A simple form of multiprocessing
is coprocessing. A coprocessor is optimized for specific tasks, such
as computations or graphics. The coprocessor speeds processing by
executing specific types of instructions while the processor works on other
instructions or activities.
Parallel Processing. Another form of
multiprocessing is parallel processing, in which computers have multiple
processors. Massively parallel computers use flexibly connected networks
of microprocessors. As opposed to parallel processing, where small
numbers of powerful but expensive microprocessors are linked together,
massively parallel machines link thousands of inexpensive, commonly used
chips to address large computing problems, attaining supercomputer speeds.
With this type of machine, business problems are broken into many parts.
Each part is assigned to a processor and the results are reassembled to
obtain a final solution.
With enough chips networked together, massively
parallel machines can perform more than a trillion floating point operations
per second (teraflops). A floating point operation is a basic computer
arithmetic operation, such as addition or subtraction, on numbers that
include a decimal point.
Parallel processing architectures can be divided
into two broad areas: single instruction/multiple data (SIMD) and
multiple instruction/multiple data (MIMD). SIMD computers execute
the same instruction on many data values simultaneously. MIMD connects
a number of processors that run different programs or parts of programs
on different data sets. MIMD computers can further be subdivided
into shared-memory and distributed-memory machines.
In shared-memory MIMD computers, all processors
access a common memory via a shared high-speed bus. Communications
among processors is easy because each processor leaves its answer in memory
and tells the other processors the address in memory at which to find the
answer. The disadvantage is that many processors must share the same
bus, making it possible that processors must wait to use the bus.
In distributed-memory MIMD systems, each
processor has its own memory store and communicates via high-speed buses.
That is, every computing node is a complete computer, each with its own
local memory. Because nodes cannot access other nodes’ private memory,
results must be passed among nodes over a communication network.
With distributed-memory MIMD computers, the speed of the network is the
limiting factor.
Scalability is the biggest advantage of distributed-memory
systems over shared-memory systems. As shared-memory machines add processors,
the overall system performance may degrade due to bus contention.
As processors are added in distributed-memory computers, the processing
power increases linearly. The biggest disadvantage of distributed-memory
machines is that they are difficult to program.
DNA Computers
A recent advance in computing is called DNA computing,
which takes advantage of the fact that information can be written onto
individual DNA molecules. This information uses the alphabet of four
bases that all living organisms use to record genetic information.
DNA computations code a problem into this alphabet and then create conditions
under which DNA molecules are formed that encode all possible solutions
of a problem. The process produces billions of molecules encoding
wrong answers, and a few encoding the right one. Modern molecular
genetics has chemical procedures that can reliably isolate the few DNA
molecules encoding the correct answer from all the others.
Although DNA computers are useful for only a small
number of problem types, they do process in parallel and are potentially
twice as fast as today’s fastest supercomputers. They also have the
potential for storage capacities one trillion times greater than current
storage media.
COMPUTER HIERARCHY
Computers may also be distinguished on the basis
of their processing capabilities. Computers with the most processing
power are also the largest and most expensive.
Supercomputers
Supercomputers are the computers with the most processing
power. The primary application of supercomputers has been in scientific
and military work, but their use is growing rapidly in business as their
prices decrease. Supercomputers are especially valuable for large
simulation models of real-world phenomena, where complex mathematical representations
and calculations are required, or for image creation and processing.
Supercomputers are used to model the weather for better weather prediction,
to test weapons nondestructively, to design aircraft (e.g., the Boeing
777) for more efficient and less costly production, and to make many sequences
in motion pictures (e.g., “Star Wars” and “Jurassic Park”). Supercomputers
generally operate at 4 to 10 times faster than the next most powerful computer
class, the mainframe.
Cray is a leading supercomputer manufacturer.
Many firms use Cray supercomputers. For example, Nissan became the
first Cray user in the Japanese automobile industry in 1986. Nissan
reports that Cray systems have played a significant role in improving quality,
reducing costs, and shortening development time in their automotive development
processes.
Supercomputers and Weather Forecasting
In April 1997, the National Oceanic and Atmospheric
Administration (NOAA) moved to enhance the United States’ weather forecasting
capability. NOAA announced that it would provide $18 million over
three years to establish the International Research Institute (IRI), which
is dedicated to providing early warnings of climate variability that influences
drought, floods, and other destructive weather patterns around the world.
IRI scientists rely heavily on Cray supercomputers and Silicon Graphics
workstations to produce, manipulate, and analyze climate models.
To determine how the weather will likely affect
various global regions, the scientists use output from three coupled ocean-atmosphere
computer models to forecast sea-surface temperatures. Each of these
models takes into account the sea-surface temperature variations over history
and each processes the information using slightly different calculations
for various weather factors. The scientists statistically “blend”
the models to get a consensus forecast. The scientists then use a
Cray supercomputer to run several general atmospheric circulation models,
which rely in part on information contained in the sea-surface temperature
models to produce complete forecasts for different regions of the world.
(Source: www.cray.com/products)
Question: Besides sea-surface temperature
variations, what other variables would you include in a model to predict
the weather?
Question: It would be cheaper to use a mainframe
for weather prediction models. Why do the IRI scientists need a supercomputer?
Mainframe Computers
Mainframes are not as powerful and generally not
as expensive as supercomputers. Large corporations use mainframe
computers for centralized data processing and maintaining large databases.
Applications that run on a mainframe can be large and complex, allowing
for data and information to be shared throughout the organization.
Examples of mainframe applications include airline reservation systems,
corporate payroll, and student grade calculation and reporting.
A mainframe system may have anywhere from 50 megabytes
to several gigabytes of primary storage. On-line secondary storage
may use high-capacity magnetic and optical storage media with capacities
in the gigabyte to terabyte range. Additionally, off-line storage
often uses high-capacity magnetic tape systems. Typically, several
hundreds or thousands of on-line computers can be linked to a mainframe.
The size, power consumption, and cost of mainframe
computing have dramatically decreased. Today’s most advanced mainframes
perform at more than 1000 MIPS and can handle up to one billion transactions
per day.
Recentralization of the Computing Resource
Recentralization, which means moving computer-based
applications back to large
servers (i.e., mainframes) from desktop machines and smaller, midrange
servers, is gaining momentum at medium and large-sized firms. The
reasons for the shift include supporting the high transaction levels associated
with electronic commerce, reducing the total cost of ownership of distributed
systems, simplifying administration, reducing support personnel requirements,
and improving system performance. In addition, host computing is
less expensive than distributed computing and provide a secure, robust
computing environment in which to run strategic, mission-critical applications.
Chrysler began consolidating manufacturing, finance,
decision-support, and other applications onto Sun and IBM hosts in 1996,
and has realized three benefits. First, Chrysler has noted a decrease
in total cost of ownership, resulting from lower hardware-acquisition costs,
reduced maintenance, and higher availability. Second, Chrysler has
experienced improved capacity and resource utilization, allowing, for example,
one server to support data inquiries during the day and batch transactions
at night. Also, several servers can share a single host storage device.
Third, the standardized environment that resulted from recentralization
has reduced application development time.
(Source: Garvey, M. J. “Mainframes Bounce
Back.” InformationWeek, July 7, 1997;14-15.)
Question: What are the disadvantages associated
with recentralizing the computing resource?
Minicomputers
Minicomputers, also called midrange computers, are
relatively small, inexpensive, and compact computers that perform the same
functions as mainframe computers, but to a limited extent. Minicomputers
are usually designed to accomplish specific tasks such as process control,
scientific research, and engineering applications. IBM is the market
leader in minicomputers with its AS/400 series of computers.
Larger companies gain greater corporate flexibility
by distributing data processing with minicomputers in organizational units
instead of centralizing computing at one location. These minicomputers
are connected to each other and often to a mainframe through telecommunication
links. The minicomputer is also able to meet the needs of smaller
organizations that would rather not utilize scarce corporate resources
by purchasing larger computer systems.
For example, the city council of Parramatta, a city
close to Sydney, Australia, handles hundreds of inquiries on a daily basis,
from dog licenses to development applications, and parking fines to property
ownership. Recently, the council purchased an AS/400 with 64-bit
RISC processing. The AS/400 system resulted in extraordinary performance
gains over its old methods of manually handling the inquiries. Response
times to customer inquiries were reduced by more than 80 percent in some
instances, and batch reporting that had taken several hours with the city’s
old mainframe computer was cut in half.
Workstations
Vendors originally developed desktop engineering
workstations, or workstations for short, to provide the high levels of
performance demanded by these users. Workstations are typically based
on RISC (reduced instruction set computing) architecture and provide both
very high-speed calculations and high-resolution graphic displays.
These computers have found widespread acceptance within the scientific
community and, more recently, within the business community.
The distinction between workstations and personal
computers is rapidly blurring. The latest personal computers have
the computing power of recent workstations. Low-end workstations
are now indistinguishable from high-end personal computers.
Physician Professional Services (PPS) is a full-service
billing and information management organization. Created and managed
by physicians for physicians, the firm monitors the latest trends in reimbursement,
payment methodologies, government and insurance carrier guidelines, laws,
and regulations. Its mission is to help physicians meet financial
goals and effectively manage patient data so they may deliver quality patient
care. To meet these objectives, PPS uses IBM’s RISC System/6000 Workstation
with data on 400,000 patient visits and about 150,000 active patient registrations.
The workstation manages 3,000 transactions, and 1000 documents, per day
– charges, payments, and daily financial activity. It has reduced
backup time from 5.5 hours to two, from 23 reels of tape to one 8 mm cartridge.
Month-end closes went from three hours to 14 minutes.
Microcomputers
Microcomputers (also called micros or personal computers)
are the smallest and least expensive category of general-purpose computers.
They may be subdivided into four classifications based on their size:
desktops, laptops, notebooks, and palmtops.
The desktop personal computer is the typical, familiar
microcomputer system which has become a standard tool for business and,
increasingly, the home. It is usually modular in design, with separate
but connected monitor, keyboard, and CPU. In general, modern microcomputers
have between 32 and 256 megabytes of primary storage, one 3.5 inch floppy
drive, a CD-ROM drive, and several gigabytes or more of secondary storage.
Network computers, also called thin clients,
are computers that do not have the full functionality of typical desktop
machines, and allow users to access a network. It is unlikely that
network computers will cause today’s personal computers to become obsolete.
Instead, NCs will become another option for the company. NCs work
best in the following situations:
Users who work with a limited set of programs. These users might
range from secretaries, who spend the majority of their
time on word processing, to top-level executives, who primarily interact
with electronic mail.
Shared desktops. The corporate world is moving away from the model
of one person for one office. Virtual workgroups, which may be comprised
of consultants, contractors, part-time employees, and full-time employees,
form regularly. Purchasing a personal computer for every individual
who might need one is not cost-effective. Because network computers
store user-specific configuration data on the server (and not locally),
they can be easily shared, while still allowing each employee to enjoy
his or her personalized working environment.
Remote users who are difficult to support. As telecommuting becomes
more prevalent, the cost and difficulty of supporting remote users has
grown exponentially. As there are few components in a network computer,
there is less that can go wrong and therefore less to fix.
Whenever security is critical. Conventional desktop and laptop personal
computers store information on local hard drives and give users virtually
unlimited access in local storage. NCs store everything on the server
and are generally safer because server rooms are more physically secure
than the typical machine sitting on the desktop. In addition, network
managers regularly back up their servers.
Network computers are not only less expensive than
standard personal computers, but accrue additional cost-benefit over the
life of the computer. Savings can be achieved with NCs through less
technical support, less training for users, and less frequent replacement
because NCs do not become obsolete as quickly as personal computers.
Network Computers at Fred Meyer, Inc.
Fred Meyer, Inc., with $15 billion in sales, has
become one of the nation’s five largest food and drug retailers through
strategic acquisitions of several major regional grocery retailers.
Part of the reason for Fred Meyer Inc.’s success has been its strategic
use of technology in all its operations – integrated merchandising logistics
and inventory management systems. With one of the recent acquisitions,
Smith’s Food and Drug Centers, a 156 store Western supermarket chain, Fred
Meyer Inc. faced a difficult problem. To deploy Fred Meyer Inc.’s
pharmacy system at Smith’s, the company would have to place both terminals
and personal computers in the pharmacy service counters. This process
would result in both an administrative headache for IT, and a problem for
employees.
However, Fred Meyer Inc.’s CIO had a solution –
network computers. She had compelling reasons for using NCs.
They connect to regular computer monitors and display the same personalized
programs as on a personal computer, such as the Internet or Windows and
mainframe applications. But, instead of depending on built-in memory
and local disk drives, which can be an entry point for viruses and incompatible
software, NCs get information, such as corporate and personal files, from
more reliable servers. Rather than replacing multiple, obsolete personal
computers every two years, and updating the software on everyone’s desktop
every time there was an upgrade, changes need only be made to the few servers
to which the NCs are connected. This solution was much cheaper and
more efficient that keeps performance, hardware, and software up to date.
After testing the NCs in the Fred Meyer IT lab and
deploying them in a pilot at a Fred Meyer store, the CIO was convinced
that the NCs could provide access to the applications that Smith’s pharmacy
personnel needed, namely Unix applications residing on local workstations,
and mainframe applications located on a remote mainframe at headquarters.
She also felt that there would be a lower total cost of ownership than
with personal computers.
Fred Meyer Inc. is also planning to use NCs in other
ways. The company is planning to provide NCs with Lotus’ suite of
productivity applications to employees who do not require personal computers.
With NCs, employees will be able to access company e-mail and the company
intranet. Instead of distributing training CD-ROMs to each store,
employees will use NCs to access the latest training programs on a server
at headquarters.
(Source: www.pc.ibm.com/networkstation).
Question: As a CIO, would you feel safe using
only network computers? Discuss why or why not.
Question: Relate the Fred Meyer case to the
statement: “The network is the computer.”
Laptop Computers and Notebook Computers
As computers become much smaller and vastly more
powerful, they become portable and new ways of using them open for users.
Laptop or notebook computers are small, easily transportable, lightweight
microcomputers that fit easily into a briefcase. Laptops and notebooks
are designed for maximum convenience and transportability, allowing users
to have access to processing power and data without being bound to an office
environment
Palmtop Computers
Palmtop computers are hand-held microcomputers,
small enough to carry in one hand. Although still capable of general-purpose
computing, palmtops are usually configured for specific applications and
limited in the number of ways they can accept user input and provide output.
Personal Digital Assistants
A personal digital assistant (PDA) is a handheld,
palmtop computer that uses a pen rather than keyboard input. PDAs
provide electronic notepad, calendar, and wireless communication capabilities.
PDAs differ from other personal computers in that they are usually specialized
for individual users. Users must train their PDAs to recognize their
handwriting by writing each letter and digit several times. The PDA
may be thought of as a computing appliance, rather than a general-purpose
computing device.
To facilitate input, PDAs are designed to work with
handwriting recognition as well as software that may anticipate a user’s
intentions. For example, a user with a PDA simply has to jot down
“Call John” for the PDA to bring up an address book with phone numbers
for all entries with the name John. By selecting the appropriate
entry, a wireless link can be used to make the connection. Wireless
connections are also used to link into a wide array of services such as
electronic mail (E-mail), electronic information sources, and electronic
paging. Infrared connection to local area networks may also be accomplished
with PDAs.
Pen-based input appeals to people who do not like to use keyboards
(e.g., executives) or who cannot conveniently use a keyboard in their work.
For example, restaurant waiters can transmit orders directly from your
table to the kitchen and then use the PDA to get your signature for a credit
card charge. Salespeople can use PDAs to provide wireless connections
to their headquarters, home, or the Internet.
At present, PDAs recognize text written in unconnected
block printing, with each character printed separately in uppercase with
the electronic stylus on the screen. This recognition is only 90-95
percent accurate. The problems of entering text with a stylus mandate
alternate modes of entry. For example, you can delete a word by crossing
it out on the screen. Tapping the stylus on the name of a stored
document will bring it onto the screen. Text can also be entered
by tapping with the stylus on the appropriate letters from an on-screen
virtual keyboard.
PDAs are used on the Chicago futures exchange, where
commodities are traded. PDAs replace the paper cards that the traders
used that encouraged fraud. PDAs provide instant matching of seller
to buyer as well as a crucial audit trail to make sure that the customers’
trades are properly executed. The PDAs include a radio transmitter
that instantly broadcasts the data on each trade to the exchange’s computers.
An example of a PDA is the PalmPilot III, made by
U.S. Robotics, which offers seven applications: a date book, an address
book, a to-do list, a notepad, an expense report, e-mail, and a calculator.
To exchange data between PalmPilots, users can beam information from one
PalmPilot III to another using an infrared port. The PalmPilot III
requires users to learn its Graffiti pen-input alphabet. Users can
place the PalmPilot III into a docking cradle and synchronize their PalmPilots
with their personal computers.
Computing Devices
Wearable computers free their users’ movements.
An electric utility has given their technicians wearable computers to free
them from having to carry cumbersome paper manuals. The device is
strapped to their belts and the display unit is positioned close to the
eye. A microphone can receive spoken commands directed at the unit
or at a remote server and transmit them by wireless telecommunications.
Wearable computers developed at Carnegie Mellon
University include a position-sensing facility that continually determines
the user’s location within a geographic area. Knowing this, the computer
can provide the user with information relating to his or her current position.
The military is currently performing research for combat troops.
Media Lab at MIT has a smart-clothes project.
Microprocessors, cameras, microphones, and sensors that are built into
your clothing enable the system to “know” your environment and help you
as an intelligent assistant. The goal of the project includes supplying
the names of the people you meet or giving you directions to your next
appointment. If a business associate mentions an impending merger
and acquisition to you, the system will “hear” and project the details
of the project onto the display in your glasses.
Embedded computers are placed inside other
products to add features and capabilities. For example, the average
mid-sized automobile has over 3,000 embedded computers that monitor every
function from braking to engine performance to seat controls with memory.
Active badges have been introduced by Xerox
to be worn as ID cards by employees who wish to stay in touch at all times
while moving around the corporate premises. The clip-on badge contains
a microprocessor that transmits its (and its wearer’s) location to the
building’s sensors, which send it to a computer. When someone wants
to contact the badge wearer, the phone closest to the person is identified
automatically. When badge wearers enter their offices, their badge
identifies them and logs them on to their personal computers.
Memory buttons are nickel-sized devices that
store a small database relating to whatever it is attached to. These
devices are analogous to a bar code, but with far greater informational
content and a content that is subject to change. The U.S. Postal
Service is placing memory buttons in mailboxes to improve collection schedules.
An even smaller form of computer is the smart card. Similar
in size and thickness to ordinary plastic credit cards, smart cards contain
a small processor and memory that allow these “computers” to be used in
everyday activities such as personal identification and banking.
Uses for smart cards are appearing rapidly.
People are using them as checkbooks; a bank ATM (automatic teller machine)
can “deposit money” into the card’s memory for “withdrawal” at retail stores.
Many states and private health maintenance organizations are issuing smart
health cards that contain the owner’s complete health history, emergency
data, and health insurance policy data. Smart cards are being used
to transport data between computers, replacing floppy disks. Adding
a small transmitter to a smart card can allow businesses to locate any
employee and automatically route phone calls to the nearest telephone.
Smart cards have caught on in much of the world,
but not in the United States. The reason is that consumers and other
users are not sold on smart cards’ benefits. For example, Oklahoma
State University has offered smart cards for use at its sports facilities
since January 1997, but sales have been slow. Also, the public’s
lack of “comfort” with smart cards could be an obstacle to widespread acceptance.
Another reason is America’s superior telecommunications infrastructure.
This infrastructure permits reliable and affordable electronic transactions,
so that credit cards, with their magnetic stripes, can be easily and quickly
verified with a connection to the card-issuing company. But, in other
countries, telecommunications networks are not nearly as reliable, cheap,
or even available as they are in the U.S. In those countries, smart
cards work well, because they are self-contained devices and do not require
connections to a central location.
For example, Germany has distributed smart cards
containing health-care information – not personal medical histories, but
payment-processing information – to all its citizens. The program
has reduced claims-processing costs by 35%, so the system paid for itself
in 18 months.
Many proponents of smart cards say that what is
missing in the U.S. is a business justification – the “killer application.”
Visa and Siemens Corporation may have an answer. They are launching
a test that will give Siemens’ employees a smart card for travel.
The cards will ensure that when the employees are on the road, they will
pay only the rates Siemens has negotiated with selected hotels, airlines,
and car-rental companies. If the smart cards work as planned, they
could help Siemens recover the $1 million a year the company says it loses
because traveling employees are not always charged Siemens’ negotiated
rates.
Another form of smart card has become common with laptop and palmtop
computers – the Personal Computer Memory Card International Association
(PCMCIA) card. With computers that have corresponding PCMCIA connectors,
these cards allow users to add capabilities such as faxing and connections
to networks, to add more primary memory, or to run specialized application
software.
INPUT/OUTPUT DEVICES
The user interface is the most important component
of a computer system to the user.
Input and output devices are integral parts of this human-computer
interface, which includes other hardware devices and software that allow
humans to interact with computer systems. The user interface is the
most important component of a computer system to the user.
The input/output (I/O) devices of a computer are
not part of the CPU, but are channels for communicating between the external
environment and the CPU. I/O devices are controlled directly by the
CPU or indirectly through special processors dedicated to input and output
processing. Data and instructions are entered into the computer through
input devices and processing results are provided through output devices.
There are numerous input and output devices.
It is critically important for organizations to
have fast, accurate data input into their computer systems. If the
data are not accurate, the acronym, GIGO (garbage-in-garbage-out) comes
into play. Getting data into the computer usually requires transferring
human-readable data into the computer and translating these data into machine-readable
data. Human-readable data can be directly read and understood by
humans, where machine-readable data can be understood and read by computer
devices (e.g., the universal bar code read by scanners at grocery checkouts).
Data may be human-readable and machine-readable (e.g., magnetic ink on
bank checks).
Humans may enter data into a computer, mainly through
a keyboard, mouse, or touchscreen. This type of data entry is prone
to error. An alternative form of data entry is source data automation,
which captures data in computer-readable form at the moment the data are
created. Point-of-sale systems, optical bar-code scanners, other
optical character recognition devices, handwriting recognizers, voice recognizers,
digitizers, and cameras are examples of source data automation. Source
data automation eliminates errors arising from human data entry and allows
for data to be captured directly and immediately, with built-in error correction.
Human Data Entry Devices
Users can command the computer and communicate with
it by using one or more input devices to trigger the action language.
The action language is how the user tells the computer what to do.
Users want communication with computers to be simple, fast, and error free.
Therefore, a variety of input devices fit the needs of different individuals
and applications. In this section, we will deal with the following
devices: keyboard, mouse, touchscreen, light pen, and joy sticks.
Keyboards. The most common input device
is the keyboard. The keyboard is designed like a typewriter but with
many additional special keys. Most computer users utilize keyboards
regularly. However, a number of computer users have developed repetitive
stress injury which they allege comes from excessive use of poorly designed
keyboards. As a result, new keyboards have been developed that are
better designed ergonomically. For example, some keyboards are now
split in half with large wrist rests, more closely approximating the natural
angle of the arms and wrists.
DataHand Systems of Phoenix, Arizona has developed
the DataHand keyboard, which consists of two unattached pads. Rather
than a conventional array of keys, the device has touch-sensitive receptacles
(or finger wells) for the fingers and thumbs. Each finger well allows
five different commands, which are actuated by touching one of the sides
or the bottom of the finger wells. Complex commands can be programmed
so that a single flick of the finger can be used to enter frequently used
sequences of commands or chunks of data.
Mouse. The mouse is a hand-held device
used to point a cursor at a desired place on the screen, such as an icon,
a cell in a table, an item in a menu, or any other object. Once the
arrow is placed on an object, the user clicks a button on the mouse, instructing
the computer to take some action. The use of the mouse reduces the
need to type in information or use the slower arrow keys. Special
types of mouse are rollerballs and trackballs, used in many portable computers.
A new technology called glide-and-tap allows fingertip cursor control.
Touch Screen. An alternative to the
mouse or other screen-related devices is a touch screen. The user
activates an object on the screen by touching it with his or her finger.
Light Pen. A light pen is a special
device with a light-sensing mechanism which is used to touch the screen.
Pointing with a light pen is more accurate than touch screens because you
can point at very small objects.
Joy Sticks. Joy sticks are used primarily
at workstations that can display dynamic graphics. They are also
used to play video games. The joy stick moves and positions the cursor
at a desirable object on the screen.
Source Data Automation
The object of source data automation is to collect
data without human intervention. This process speeds up data collection,
reduces errors, and gathers data one time and at the source of the transaction.
Automated Teller Machines. Automated
teller machines (ATMs) are interactive input/output devices that enable
people to obtain cash in many locations and updating their bank accounts
instantly. ATMs can handle a variety of banking transactions, including
the transfer of funds to specified accounts. One drawback of ATMs
is their vulnerability to computer crimes and to attacks made on customers
as they use outdoor ATMs.
Point of sale terminals. Many retail
organizations utilize point of sale (POS) terminals. The POS terminal
has a specialized keyboard. For example, the POS terminals at McDonald’s
include all the items on the menu, often in labeled with the picture of
the item. POS terminals in a retail store is equipped with a scanner
that reads the bar-coded sales tag. POS devices increase the speed
of data entry and reduce the chance of errors. POS terminals may
include many features such as scanner, printer, voice synthesis, and accounting
software.
Bar Code Scanners. Bar code scanners
scan the black-and-white bars written in a code called the Universal Product
Code (UPC). This code specifies the name of the product and its manufacturer.
Bar codes are especially valuable in high-volume tracking where keyboard
entry is too slow and/or inaccurate. Applications include supermarket
checkout, airline baggage stickers, and Federal Express packages.
The wand reader is a special hand-held bar code reader that can read codes
that are also readable by people.
The Uniform Code Council (UCC) has proposed a 14-digit
bar code called reduced space symbology (RSS) that, if adopted by the supermarket
industry, allows produce to be tracked the same way other items in the
store are. Produce sections currently have fruits and vegetables
with four digit bar codes. The lack of digits prevents stores from
differentiating certain produce items from others. RSS will allow
retailers to track international goods that are labeled using 13-digit
codes and incorporate a 14th digit that represents a case of produce as
one digit, allowing stores to sell in bulk more easily.
Optical Mark Reader. The optical mark
reader is a special scanner for detecting the presence of pencil marks
on a predetermined grid, such as multiple-choice answer sheets.
Optical Character Reader (or Optical Scanner).
With an optical scanner, source documents such as reports, typed manuscripts,
and books can be entered directly into a computer without the need for
keying. An optical scanner converts text and images on paper into
digital form and stores the data on disk or other storage media.
Optical scanners are available in different sizes and for different types
of applications.
The publishing industry is a leading user of optical
scanning equipment. Publishers scan printed documents and convert
them to electronic databases that can be referenced as needed. Similarly,
they may scan manuscripts instead of retyping them in preparation for the
process that converts them into books or magazines. Considerable
time and money are saved, and the risk of introduction typographical errors
is reduced. Scanners are becoming increasingly more reliable.
Some are sophisticated enough to read not only text but visuals such as
photos, illustrations, and graphs.
Magnetic Ink Character Readers. Magnetic
ink character readers (MICR) read information printed on checks in magnetic
ink. This information identifies the bank and the account number.
On a canceled check, the amount is also readable after it is added in magnetic
ink.
Handwriting Recognizers. Today’s scanners
are good at “reading” typed or published material, but they are not very
good at handwriting recognition. Handwriting recognition is supported
by technologies such as expert systems and neural computing and is available
in some pen-based computers.
Scanners that can interpret handwritten input
are subject to considerable error. To minimize mistakes, handwritten
entries should follow very specific rules. Some scanners will flag
handwritten entries that they cannot interpret or will automatically display
for verification all input that has been scanned. Because handwritten
entries are subject to misinterpretation and typed entries can be smudged,
misaligned, and/or erased, optical scanners have an error rate much higher
than the error rate for keyed data.
Pen-based input devices utilize handwriting
recognition. These devices consist of a flat-screen display tablet
and a pen-like stylus. Users print directly onto the tablet-sized
screen. The screen is fitted with a transparent grid of fine wires
that detects the presence of the specialized stylus, which emits an electronic
signal from its tip. The screen can also interpret tapping and flicking
gestures made with the stylus.
Pen-based input devices transform the letters and
numbers written by users on the tablet into digital form, where they can
be stored or processed and analyzed. At present, pen-based devices
cannot recognize free-hand writing very well, so users must print letters
and numbers in block form.
At high-tech meetings, it is not unusual to see
everyone around a conference table using laptop computers. In many
settings, however, such behavior is unacceptable. In Europe and Asia,
it is completely unacceptable, and the use of laptops is prohibited in
some places such as courtrooms and in the U.S. Congress. Further,
computer keyboards are not great for note-taking. It’s difficult
to type diagrams, flow charts, graphs, or equations into a computer.
As a result, A.T. Cross has developed an alternative interface to computers,
called the CrossPad.
The CrossPad is similar to an electronic clipboard.
The user slips in a pad, picks up the special pen supplied with the device,
and can store up to 50 handwritten pages in the CrossPad’s memory.
Users can connect the clipboard to the serial port on a Windows 95 personal
computer and a facsimile of the handwritten pages is input into the PC.
Users could accomplish the same thing by running
their written notes through a scanner, but the CrossPad is more convenient
and comes with interesting IBM software. If you tap a button on the
CrossPad and then circle a word or phrase on your sheet of paper, it will
be converted to text and recognized as a keyword when you copy the writing
to your PC. This process makes it simple to store indexed, searchable
copies of handwritten documents on your computer. Software also makes
it possible to use the CrossPad to fill in printed forms, an approach that
many health-care workers and others who spend much of their working lives
filling in forms may find simpler and more natural than a laptop or handheld
computer.
Users must invest an average of 45 minutes in training
the device to read their writing. However, users find that they can
fix any errors much faster than they could type in all the text.
Voice Recognizers. The most natural
way to communicate with computers is by voice, using a natural language
(called natural language processing). Voice recognition devices convert
spoken words into digital form. Voice recognition devices are extremely
important because they are fast, free the user’s hands, and result in few
entry errors. They also allow people with visual or other disabilities
to communicate with computers. When voice technology is used in combination
with telephones, people can call their computers from almost any location.
While voice technologies have certain limitations such as the size of the
vocabulary, they are rapidly improving.
To understand a natural language inquiry, a computer
must have sufficient knowledge to analyze the input in order to interpret
it. This knowledge includes linguistic knowledge about words, domain
knowledge, common sense knowledge, and even knowledge about users and their
goals.
Sensors. Sensors are devices that collect
data directly from the environment for input into a computer system.
Digitizers. Digitizers are devices
that convert drawings made with a pen on a sensitized surface to machine-readable
input. As drawings are made, the images are transferred to the computer.
This technology is based on changes in electrical charges that correspond
to the drawings. Digitizers are used by designers, engineers, and
artists.
Cameras. Regular video cameras can
be used to capture pictures that are digitized and stored in computers.
Special cameras are used to transfer pictures and images to storage on
a CD-ROM. A digital camera can take photos and load them directly
from the camera, digitally, to a main storage or secondary storage device.
Hewlett-Packard produces the PhotoSmart C20 digital camera which sells
for approximately $700. Features include a 1.8 inch LCD screen, flash,
camera-to-TV video port, autofocus, removable memory, and a lens cover
that, when removed, powers up the camera. The C20 has 1,152 x 872
pixel resolution. Depending on the resolution or quality the user
selects, the C20 stores beetween 8 and 40 pictures on its 4 MB compact
flash pop-out memory card.
Output Devices
The output generated by a computer can be transmitted
to the user via several devices and media. The presentation of information
is extremely important in encouraging users to embrace computers.
Monitors. The data entered into a computer
can be visible on the computer monitor, which is basically a video screen
that displays both input and output. Monitors come in different sizes,
ranging from inches to feet, and in different colors. The major benefit
is the interactive nature of the device. Monitors display information
in a softcopy form, and they are used in most of the interface modes.
Monitors employ the cathode ray tube (CRT) technology,
in which an electronic “gun” shoots a beam of electrons to illuminate the
pixels (picture elements) on the screen. The more pixels on
the screen, the higher the resolution. For example, a screen with
a 1024 x 768 resolution (786,432 pixels) would have greater clarity than
one with a resolution of 640 x 350 pixels (224,000 pixels). The dot
pitch is the distance between pixels on the screen. The smaller
the dot pitch, the larger the number of pixels on a given screen and the
higher the resolution. A dot pitch of .28 mm or smaller is considered
to be high quality.
CRT monitors can be classified as monochrome or
color and by their display capabilities. Some monitors display only
text, where others display both text and graphics.
Portable computers use a flat screen consisting
of a liquid crystal display (LCD). Flat-panel displays are
shallow-depth video displays based on solid-state technology. Sizes
vary from the 12-inch flat-panel screens found on notebook and laptop computers
to the 17-inch flat-panel displays now being introduced for desktop computers,
to wall-sized flat-panel monitors used in videoconferencing and home entertainment.
LCDs consume less power than traditional monitors.
For example, LCDs consume less than half the power that a 15-inch desktop
monitor uses. However, today’s flat-panel displays are roughly six
to eight times the cost of an equivalent CRT.
Passive-matrix LCDs are used in applications where display speed and
color brightness are not essential. More advanced active-matrix LCDs
appear to function as one large integrated circuit, but actually are composed
of hundreds of thousands of individually illuminated thin film transistors.
As a result, LCDs eliminate the flicker associated with CRTs.
Currently, NEC Corporation is developing a 20-inch
flat-panel display for desktop computers. This panel increases the
viewing angle to be comparable to that of standard monitors. In addition,
Sharp Electronics Corporation’s line of desktop replacement displays delivers
viewing angles of more than 70 degrees in three directions.
Screen sizes on notebooks and laptops are increasing.
Thirteen-inch screens are appearing on high-end laptops, the largest size
practical for mass-production laptops because anything larger would be
wider than the keyboard.
Plasma displays are normally a few inches
thick and weigh much less than CRT monitors. As a result, plasma
display technology is appropriate for large-screen displays such as those
used on the trading floors of the New York Stock Exchange.
Field emission display (FED) is an emerging display technology that
combines the best features of standard cathode-ray tube displays and flat-panel
technologies. Like CRTs, field emission displays rely on light emitted
from phosphors that have been excited by electron beams. However,
like flat panels, FEDs are thin and can be made using standard semiconductor
fabrication processes. In addition, FEDs offer unlimited viewing
angles.
Impact Printers. Like typewriters,
impact printers use some form of striking action to press a carbon or fabric
ribbon against paper to create a character. Serial printers print
one character at a time. The most common serial printers are the
dot matrix, daisy wheel, and line. Line printers print one line at
a time; therefore, they are faster than other serial printers. Impact
printers are slow and noisy, cannot do high-resolution graphics, are often
subject to mechanical breakdowns, but they are inexpensive.
Nonimpact Printers. Nonimpact printers
overcome the deficiencies of impact printers, but they are more expensive.
Laser printers are higher speed, high-quality devices that use laser beams
to write information on photosensitive drums, whole pages at a time; then
the paper passes over the drum and picks up the image with toner.
Because they produce “print” quality text and graphics, laser printers
are used in desktop publishing and in reproduction of artwork. Thermal
printers create whole characters on specially treated paper that responds
to patterns of heat produced by the printer. Ink-jet printers shoot
tiny dots of ink onto paper. Sometimes called bubble jet, they are
relatively inexpensive and are especially suited for graphical applications
when different colors of ink are required.
Plotters. Plotters are printing devices
using computer-driven pens for creating high-quality black-and-white or
color graphic images – charts, graphs, and drawings. They are used
in complex, low-volume situations.
Voice Output. Some devices provide
output via voice – synthesized voice. This term refers to the technology
by which computers “speak.” The synthesis of voice by computer differs
from a simple playback of a prerecorded voice by either analog or digital
means. As the term “synthesis” implies, the sounds that make up words
and phrases are constructed electronically from basic sound components
and can be made to form any desired voice pattern. The quality of
synthesized voice is currently very good, and relatively inexpensive.
Multifunction Devices
Multifunction devices combine a printer, fax machine,
scanner, and copy machine into one device. Multifunction devices
are cheaper than buying specific devices separately and they take less
space on a desktop. The Hewlett-Packard LaserJet 3100 is a multifunction
device. This device prints at 600 dots-per-inch black-only output
at six pages per minute. It also adds scanning, copying, and a sophisticated
fax machine to the package.
In addition, the 3100 can be controlled through
your personal computer using JetSuite software from JetFax. Drop
a document to be faxed or scanned into the input slot, and a menu pops
up on your screen asking if you want to fax, copy, or scan the document.
For example, choosing “fax” allows you to fill in a cover page form, dial
the phone, and send the document to one or more recipients. You can
create documents in a word processor or other application,, then dispatch
them by “printing” to the fax machine.
MULTIMEDIA
Multimedia integrates, using information technology,
any or all of the following: text, sound, still images, animation,
and digitized motion video.
text: narrative descriptions, including words, descriptions, and
symbols;
still images: photographs, drawings, and figures, whether in black
and white, shades of gray, or full color;
audio sequences: sounds of human voices, music, special effects;
motion video sequences: integration of sound and full motion pictures;
animation sequences: succession of discrete still images that, when
played under computer control, are interpreted by the human mind as a smooth-flowing
moving picture.
Multimedia merges the capabilities of computers
with televisions, VCRs, CD players, and other entertainment devices.
Multimedia invites participation by the receiver of the information,
typically by way of a graphical user interface. The most important
advance in multimedia arising from information technology is the capability
for dynamic, interactive presentation of information. Today, recipients
of multimedia presentations have the option of making the communication
two-way.
An interactive multimedia approach involves the
use of computers to improve human-machine communication by using a combination
of media. The construction of a multimedia application is called
authoring.
Multimedia standards are necessary to enable software
and hardware vendors to build products that will work together to meet
customer requirements. The Multimedia Personal Computer Council (MPC)
was formed by Microsoft and hardware manufacturers such as NCR, Fujitsu,
and NEC. The MPC specification defines the minimum hardware requirement
for multimedia presentations. The MPC certification mark tells consumers
that the hardware has been tested by the manufacturer and found to be compliant
with the minimum hardware specifications.
IBM has provided the Ultimedia Solution, which employs
Intel digital video interactive technology and Phillips CD-I, compact disk
interactive technology. This standard defines the operating system,
hardware, and software for interactive compact disk applications.
Compact disks are the delivery medium of choice for multimedia applications,
because CDs have storage capacities of 650 megabytes. Video, image,
and audio compression technologies make it possible to deliver multimedia
applications that are rich in content and features while using less than
600 megabytes of storage.
Audio involves converting an analog signal to a
digital recording for storage on a magnetic disk or CD-ROM, and then converting
the digital recording to an analog system when the multimedia program executes.
Audio devices include CD-audio and cassette players.
The standard system for connecting musical instruments
and synthesizers to computer is the Musical Instrument Digital Interface
(MIDI). MIDI defines codes for musical events, including the start
of a note and its pitch, length, volume, and other attributes. A
MIDI card can be added to a personal computer to control audio input and
output. Users can edit music by changing the various codes in the
digital recording.
Advanced sound systems use digital signal processor
(DSP) chips to improve the analog-to-digital-to-analog conversion process.
DSP chips perform signal conversion instead of the personal computer’s
CPU.
Video, a rewarding part of multimedia presentations,
is also the most difficult element to display because a single uncompressed
frame requires about 1 megabyte of storage. It is possible to avoid
this limitation through video compression, where only the parts of successive
frames that change are stored.
Intel has developed special-purpose chips for compressing
and processing full-motion video. The Intel standard is called digital
video interactive (DVI). DVI compresses video at a 150:1 ratio, enabling
one hour of video to be stored on about 720 megabytes. Without compression,
over 110 gigabytes would be required.
Total Cost of Ownership
Business Problem
Norwest Corporation is trying to save $90 million
per year. The company feels that if it can decrease the costs of
purchasing and maintaining the firm’s 30,000 personal computers by 30%,
it can reach its goal. The question is, how will Norwest do it?
The price tag on a computer has become an increasingly
irrelevant indicator of what it really costs. One of the most important
issues facing organizations today is the total cost of ownership for their
computers. In spite of rapidly decreasing hardware costs, the total
cost of ownership continues to increase.
The initial purchase of computing equipment is relatively
small when compared with the total cost associated with maintaining and
supporting the entire information technology process in organizations today.
Other activities such as user support, training, networking, and other
facilities-related operations contribute the majority of cost of ownership
of an enterprise information system.
Equipment costs are fairly straightforward.
The acquisition price and ongoing maintenance cost are relatively clear
and are usually the starting point for a full cost-of-ownership analysis.
However, there are many other factors that must be considered. To
determine a complete cost of ownership, the following types of questions
must be answered:
What are the future upgrade costs?
What type of reliability and high availability capabilities
are required?
What level of user support will be required?
Where are the users located?
What level of training is needed?
Are the users computer-literate? (e.g., engineers
or clerical staff)
How will remote users be supported?
What level of security is needed?
The Gartner Group has developed a model for total cost of ownership
that includes the costs of four areas: end-user operations, capital,
administrative, and technical. End-user operations (40% of the TCO)
costs consist of data management, learning time, peer support, and small,
user-solvable problems. Capital costs (20% of TCO) include hardware,
software, and options. Administrative costs (20% of TCO) cover asset
management, security, auditing, installation and change management.
Technical-support costs (10% of TCO) include the help desk, configuration
review, and data extraction. On an annual basis, the Gartner Group
estimates that the TCO for each networked personal computer is approximately
$11,900.
The Business Solution(s)
In an effort to reduce their TCO and gain flexibility,
many organizations are choosing to lease their computers. These firms
say that leasing allows them to keep up with rapidly changing technology
and leaves them more cash to expand their businesses. In addition,
the cost of a lease can be deducted and a leased computer can be simply
shipped back. This process saves companies the effort and time spent
in finding a buyer for older computers. Popular lease plans run for
three years with the option to buy the machine at the end of the lease.
Hollywood Entertainment Inc., in a pilot study using network computers
in five of their video stores, found that maintenance and support costs
were cut in half.
There are several other methods that companies use
to reduce their TCO. First, standardized environments cost less to
install and maintain than heterogeneous environments. For example,
Lexmark International, a printer manufacturer, will not develop applications,
but relies on buying standard, industry-leading products from major software
vendors. Lexmark’s consistent desktop environment reduces training
costs and reduces time lost from employees tinkering with their computers.
Lexmark employs 80 people to support their 7,500 personal computers worldwide.
Electronic software distribution ensures consistent
software installation and eliminates the need to physically install software
on each computer. People’s Bank, a $7.9 billion financial institution
based in Bridgeport, Connecticut, uses electronic software distribution
and has reduced its TCO to just under $5,000 per year per computer.
The use of remote systems management tools to move
software and data to and from personal computers and to store backup images
of users’ hard drives will also reduce TCO. Atlanta-based HBO &
Co., a large healthcare services provider, has more than 800 mobile sales
representatives, all using laptop computers. With a standardized
disk image on each machine and a standardized operating environment, HBO’s
representatives dial in from hotels, homes, and client offices all over
the United States, uploading sales reports and downloading the latest competitive
intelligence and product information. Any settings that users have
changed are changed back automatically and any unauthorized software is
deleted automatically. Interestingly, each user is allowed a 50 MB
data area for ‘personal control.’ HBO uses archived disk images from
each laptop to handle laptop damage, theft, and virus attacks.
Organizations may employ automated technical support
tools to reduce support staff. The Gartner Group estimates that an
organization with 1,000 network nodes averages 72 help desk calls per day,
with each call costing between $22 and $41 to resolve. The National
Institute of Allergy and Infectious Diseases at the National Institutes
of Health uses automated support tools to allow each support person to
handle 100 to 125 users. The automated support tools also show support
personnel what users have done to bring about the problem that prompted
the call to the help desk.
What did Norwest do? The financial services
company decided to purchase NetPCs. NetPCs, slimmed-down versions
of regular, desktop personal computers which cost approximately $1000,
fall in between regular PCs and network computers. Where network
computers are $750 computers with no hard drive, NetPCs have a hard drive
and can have programs installed and run locally. Norwest also has
a standard, corporate-wide computing environment, distributes software
electronically over its network, and also performs system administration
tasks over the network.
Question: Rank the methods for reducing TCO
from the greatest effect to the least effect. Discuss your ranking.