Microcomputersin Evaluation

The New Generation of ComputersPeter J. GraySyracuse University

The major characteristics of microcomputer technology that make it souseful for evaluation research are its functionality, speed, and acceksi­bility. Functionality concerns the variety and sophistication of micro­computer software and hardware features. Speed concerns the time ittakes for software and hardware to perform the operations related totheir features. Accessibility is the extent to which functionality andspeed are available to the individual user. Accessibility depends on (1)the price! performance ratio, that is, the cost of each unit offunctionalityand speed, and (2)ease of use, that is, the extent to which the interactionbetween person and machine is intuitive. Improvements in micro­computer hardware have a major impact on the functionality, speed,and accessibility of microcomputer technology.

Hardware includes the following electronic and mechanical com­ponents of a microcomputer system:

• the system board, which has the basic pathways over whichinformation flows

• the central processing unit (CPU), which provides the most basiccontrol over the flow of information in the system

• read only memory (ROM), which controls particular systemfunctions

• random access memory (RAM), which provides active memory• special function chips and multifunction boards internal to the

microcomputer, which expand its capabilities

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• external hard disk, floppy disk, and other drives, which provide massstorage of information outside the microcomputer itself

• input devices such as keyboards, pointers (e.g., mouse), optical scanners,light pens, and graphics tablets

• data transfer components such as modems and network connectorsand their cables

• output devices such as monitors and flat screens, printers, andplotters

This installment of Microcomputers in Evaluation focuses on thesystem board, the CPU, ROM, RAM, special function chips, andmultifunction boards of a hardware system. Future installments willdiscuss the other hardware components and the software programsbeing developed to take advantage of the new hardware features . Thepurpose of this series of installments is to suggest the direction thatmicrocomputer technology will take in the next several years based onthe introduction of two new hardware systems: the Apple Macintosh IIand the IBM Personal System/2 (PS/2).

SYSTEM BOARDS

Both of the new hardware systems have as their foundation a newsystem board. In addition to the basic pathways for the flow ofinformation, system boards have the chip sockets, expansion slots, andports for connecting other hardware components to them. The two newsystem boards are named the NuBus (Macintosh II) and the MicroChannel bus (PS/2). The NuBus was originally designed by people atthe Massachusetts Institute of Technology and was previously used incomputers specifically intended for computer engineering uses (Keenan,1987:37).The Micro Channel bus was developed exclusivelyfor the newfamily of Personal System/2 (PS/2) machines by IBM over a three-yearperiod.

Both system boards have several important features in common.First, they are designed to support the new generation of centralprocessing units, the features of which are described in the next section.Second, the new system'boards automatically find and configure alladd-in cards . That is, without the user having to set any switchesmanually, the computer ensures that cards attached to the system board

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do not have conflicting addresses and that they are functioningcorrectly.

Third, the boards provide greater data integrity at faster transferrates than current system boards. The PS/2 system board, for example,facilitates faster data transfer by having "dedicated data paths to thevideo, memory and storage subsystems and by supporting as many aseight Direct Memory Access (DMA) controllers to transfer datasimultaneously"(Kanzler, 1987b:6). Fourth, the boards can have manycoprocessors residing in the machine, thereby distributing the workload. This feature, called parallel processing, results in the extremelyrapid processing of very complex operations such as drawing thegraphics used in computer-assisted design work or searching a very largedata base. Finally, both system boards address a 32-bit space, whichcontributes to greater speed in data transfer. That is, 32 bits ofinformation can be transferred at one time, in comparison to 8-bit and16-bit boards. The 32-bit address capability also makes it possible toaccess large amounts of random access memory, up to 4 gigabytes, or4billion bytes of information. (See also Garretson and Sussman, 1987;Moran and Foster, 1987; Miller, 1987b.)

CENTRAL PROCESSING UNITS

The brains of the new machines are their central processing units: theMotorola 68020 and 68030 (Macintosh II) and the Intel 80286 and80386 (PS/2). These CPUs have four main advantages over earliermodels: speed, addressable memory, multitasking, and color.

Speed is the most important of the advantages because the otherfeatures become advantages only when there is great processing speed.Depending on the CPU, the data transfer rate can be 10 megahertz(MHz) for an Intel 80286and 16MHz or 20 MHz for an 80386. This is incomparison with the 6 MHz and 8 MHz rates of older CPUs used incurrent IBM and compatible computers. -The difference in processingspeed is dramatic. For example, a 16 MHz system is four times fasterthan an 8 MHz system. This faster processing is essential when largeamounts of memory arc needed, as with multitasking and multicolorhigh-resolution display.

Multitasking, the ability to run more than one program at a time, isone of the most exciting features of the new CPUs. The notion of

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multitasking is like the windowing provided by the Macintosh operatingsystem and by such programs as Microsoft Windows and Quarterdeck'sDesqView for IBMs and compatibles. In these implementations, anumber of files related to a single program can be displayed in variouswindows all at the same time. With multitasking, various programscould be running in different windows all at the same time. Specialsystem software is needed for multitasking. A detailed discussion ofsuch software willbe provided in a future installment of Microcomputersin Evaluation. The purpose here is just to highlight the advantages ofmultitasking.

One advantage ofsuch a capability is that it facilitates the transfer ofdata from one program to another. There are three major categories ofprograms: generic application programs (e.g., word processing, spread­sheet, data base management, graphics), more specific applicationprograms (e.g., personal and project management, statistical analysis),and single-purpose programs (e.g., desk accessories such as notepads,outliners, and calculators). There are great time savings when all theappropriate programs can be running at once, since it is not necessary tosave the information to be transferred, quit from one program, launchanother program, and transfer the information into the second program.With multitasking the following sequence of events could occur with allprograms running at the same time: (1) Number processing could bedone with a spreadsheet or statistics program, (2) the results could bedisplayed using a built-in graphics component, (3) the graphics could betransferred to a specialized graphics program for custom formatting,and (4) the resulting graphic could be transferred to a word processor orpage-layout program, where it could be integrated with the text of areport.

A second advantage of multitasking is the ability to run one or moreprograms in the foreground while other programs are running in thebackground. An example of foreground and background multitaskingis the process of transferring files over a telecommunication link whilecontinuing with an application program such as word processing. Sincedown-loading filesvia telecommunication can be quite time-consuming,multitasking provides time savings by allowing the transfer of data toproceed in the background while the user continues with other tasks inthe foreground.

Color, the last major feature of the new CPUs, is not actually afeature of the CPUs themselves. Rather, they have the ability to supportthe enhanced color capabilities of chips plugged into the system board

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or of cards that fit into the system board slots. These are discussed in thenext section.

SPECIAL CHIPS AND MULTIFUNCTION BOARDS

On both of the new system boards there are sockets for microchipsand slots for multifunction cards. Microchips are usually designed for asingle purpose, such as providing additional random access memory,additional processing capabilities, color/graphics/video control, sound,clock/calendar functions, input device control, and disk drive control.RAM chips now come in 256 kilobyte (i.e., 256K), 512K, and Imegabyte (i.e., IM) capacities, meaning that far fewer chips have to beused to provide the large memory requirements of the new machines.The IM chips are nearly twice as fast as the smaller capacity chips. Notonly does this save space on the system board, but it also means greaterreliability, less heat generated, and faster data transfer.

Coprocessing chips include additional CPUs and mathematicscoprocessors. For example, the Mac 286 board from AST "enablesusers to execute MS-DOS applications in a standard Macintoshwindow" (Keenan, 1987: 38). This board can be used with both theMacintosh II and single-slot Macintosh SE. A soon-to-be-releasedcoprocessor board is the transputer by Levco TransLink. This boardwill "boost the number crunching power of these desktop machines tomore than 40 mips (million instructions per second)" (Keenan, 1987:38). Currently they operate at 2 to 4 mips. Mathematics coprocessorsprovide additional processing power by freeing the main CPU from thetask of calculating numbers.

The new color/graphics/video control chips are examples of very­large-scale-integration (VLSI) technology. Whereas these functionswere previously provided by several chips on an add-on board, they arenow provided by one VLSI chip plugged into the system board. Forexample, the new IBM Multi Color Video Graphics Array is "a customgraphics support chip ... [that] has 17 display modes, including modesthat take the place of CGA [Color Graphics Adapter] and EGA[Extended Graphics Adapter] cards" (Miller, 1987a:80). This new chipsupports 16 on-screen colors in higher screen resolution modes and 256colors, from a palette of 256,000 colors, in lower resolution modes. Inaddition, text is clearer with the new chip because of the higherresolution that it provides .

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Other examples of VLSI chips are the IBM direct-memory-accesschip and the Macintosh sound and video chips, which replace manyindividual chips used in previous machines. Such chips provideclockjcalendar functions, input/ output control, memory management,and other functions previously provided by boards full of chips andintegrated circuits . In addition, some companies are developing Appli­cation-Specific Integrated Circuits chips and PC on a Chip (POACH)chips. A single Application-Specific Integrated Circuits chip may takethe place of 50 ormore integrated circuits . One POACH set of two chips"replaces 75 percent of the integrated circuits on the motherboard[system board]" (Kanzler, 1987a: 17).

Cards that plug into the slots of a system board include those thatprovide the additional RAM and mass storage needed to run and savethe large programs and files that the new machines make possible. Othercards take advantage of the increased color/graphics/video capabilities.Still other cards allow individual microcomputers to be networkedtogether or to act as terminals on multiuser systems (micro, mini, ormainframe).

IMPLICATIONS

Current hardware developments represented by the new AppleMacintosh II and IBM PS/2 machines suggest three trends in hardwaresystems. The first concerns personal computers, that is, stand-alonemachines with their own CPUs, internal memories, and peripherals. Asthe price/ performance ratio of the new machines improves, they willreplace older equipment, thereby giving individual users greater pro­cessing speed, memory size, and CPU sophistication. This will makeavailable multitasking, greater screen resolution and color display, andso on.

The second trend concerns the ability of personal computers to shareperipherals (e.g., laser printers, mass storage devices such as hard diskdrives) and files. This will be accomplished via built-in network andtelecommunication links. Increasing sophistication in networking capa­bilities will result in quicker communication among machines and thesmoother transfer of files among systems on a network-even thoughthey have different CPUs and operating systems.

The third trend is the development of multiuser environments. Large

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RAM and mass storage, faster processing, parallel processing, andmultitasking enhancement will make it possible to have hardwareconfigurations that have either several CPUs, one for each terminal, orone central controller with one CPU. In either case, there will be ashared set of RAM, mass storage, and other peripheral devices.Terminals that are just keyboards, monitors, and the electroniccomponents needed to communicate with a central controller systemwill act like stand-alone computers in terms of functionality and speed.

In summary, it is the functionality, speed, and accessibility of the newmachines, which result from the next generation of system boards andtheir CPUs, that provide the platform for future improvement inmicrocomputer systems. These improvements will have a direct effecton evaluation and research through increased productivity at reducedexpense.

Hardware Sampler

IBM Modela 30 50 60 80

CPU 8086 80286 80286 80386Speed 8MHz 10 MHz 10 MHz 16/20 MHz

Standard:

RAM 640K 1M 1M 112MHard disk storage 20M 44M 44MExpansion slots 3 3 7 7Base model price· $1,695 $3,595 $5,295 $6,995

Apple Macintoshb,c SE II

CPU 68000 68020Speed 8MHz 16 MHz

Standard:

RAM 1M 1MHard disk storage 40MExpansion slots 1 6Base model price·· $3,000 $6,000

SOURCES: a. Bellamah (1987: 6); b. Green and Green (1987a); c. Green andGreen (1987b).-List prices are for base models, excluding monitors, which hst for: $250 (12·[nchmonochrome IBM Model 8503), $595 (14·inch low resolution diagonal screenColor Display IBM Model 8512), $1,550 (16-inch high resolution diagonal screenColor Display IBM Model 8514) (Abruzzese and Chabal , 1987)."List prices include monochrome monitors.

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REFERENCES

Abruzzese. G. and P. Chabal (1987) "Analog displaysoffer increasedresolution. color,IBM says." InfoWorld(ApnI6)' 81.

Bellamah, P. (1987) "New PC generation providesadded power, future flexibility." PCWeek(April 7). 1.6.

Garretson, R. and A. Sussman(1987) "IBM eyesfuture. but userswillsee benefitsnow."PC Week(April 7)' I, II.

Green.D. and D. Green(1987a) "MacintoshSE:newMacintoshspeedsup graphics,SCSIports" InfoWorld (April 13). 59-60, 62.

Green. D. and D. Green(1987b) "Macintosh II: this maynot bea dream machine.but it'sclose." InfoWorld (June 8).53-56.

Kanzler, S. (1987a) "Chip finn to duel industryleaderin ASIC market." PC Week(Apnl7): 17.

Kanzler, S. (l987b) "IBM buildsmorespeed,functioninto hardwareofits PS/2line."PCWeek(Apnl 7): 1.6.

Keenan, V. (1987) "Open Macll waiting for flood of NuBus cards." MacWEEK(December 15): 36-38.

Miller. M. J . (1987a) "Expansion bus highlights PS/2 family."InfoWorld (April 6). 80.Miller, M. J. (1987b) "Machinesset newstandard in computmg"InfoWorld(April6)' I,

82.Moran. T. and E. Foster (1987) "IBM modelsofferdiversecapabilities." InfoWorld(Apnl

6) 3.80.