The AppleMacintosh ComputerMouse-window-desktop technology arrives for under $2500by Gregg Williams

Apple established itself as one ofthe leading innovators in personalcomputing technology a year ago byintroducing the Lisa, a synthesis andextension of human-interface tech-nology that has since been widelyimitated. Now the company has

strengthened that reputation with anew machine, the Macintosh (above).In terms of technological sophistica-tion and probable effect on the mar-ketplace, the Macintosh will outdis-tance the Lisa as much as the Lisahas outdistanced its predecessors.

The Macintosh arrives, finally, aftera history of colorful rumors. It willcost from $1995 to $2495, weighs 22.7pounds, and improves on the mouse-window-desktop technology startedby the impressive but expensive Lisacomputer. A system with printer and

30 February 1984 C BYTE Publications Inc.

second disk drive costs about $900more, but even at that price, theMacintosh is worth waiting for.

The Macintosh at WorkBefore we look at the Macintosh (or

Mac) in more detail, let's look at howit works. When you turn the Mac on,its screen tells you to insert a 3 1/2-inchSony floppy disk. When you do that,the Macintosh puts a disk icon on thescreen along with the disk's name. Aswith the Lisa computer, you firstselect an object, then choose a menuitem that works on the object. Say, forexample, we choose the disk by mov-ing the cursor to the disk icon andclicking the mouse button once(figure la). The disk "opens up,"showing a window containing icons,each one of which corresponds to anitem on the disk. To start using theMac Paint program, we select theMac Paint icon and choose the menuitem "open," as shown in figure lb.(We also could have opened MacPaint by double-clicking on the icon.)

What follows is a brief example ofhow the Mac Paint program works.When we open the program, we getthe screen of figure 1c. The largeblank area is a window onto thedrawing area, the boxes on the leftare tools, the boxes on the bottomrow are patterns, and the lines in the

corner are selections for the currentline width. By selecting the "openoval" tool and the thickest line width,we can draw empty ovals with thickborders (figure 1d). By selecting the"paint bucket" tool and the "diagonalbricks" pattern, we can fill the ovalwith that texture (figure le). The"eraser" tool lets us erase part of theimage (figure 1f); for finer control, wecan give the FAT BITS command(figure 1g), which allows us to eraseor paint on a pixel-by-pixel basis.When we are finished with our im-age and select the QUIT command,the program displays an alert box thatasks if we want to save our changes(figure 1h).

Foundations of Macintosh DesignThe Macintosh computer is built on

three cornerstone ideas: second-gen-eration Lisa technology, reliabilityand low cost through simplicity, andmaximum synergy between hard-ware and software. Each of theseideas contributes significantly to theuniqueness of the Mac's design.

Second-GenerationLisa Technology

Without question, the strongest in-fluence on the Mac is that of theApple Lisa computer, which provedthe viability of certain concepts in a

commercial product: the graphics/mouse orientation, the desktop meta-phor, the data-as-concrete-objectmetaphor, and the shared user inter-face between programs. The Mac hasinherited these concepts; for furtherdetails on them, see my article, "TheLisa Computer System" (February1983 BYTE, page 33).

Four differences between the Lisaand the Mac make the latter asecond-generation computer. First,the Mac runs at a higher clock speed,7.83 MHz (compared to the Lisa's 5MHz). Second, the Mac, which hasa smaller amount of memory to workwith than the Lisa, uses its memorymore efficiently because its programsand subroutines are coded in 68000assembly language (as opposed tothe Lisa, which uses less efficient68000 machine-language programsthat are compiled from high-levelPascal source code). Third, theMacintosh eliminates add-on periph-eral cards and uses instead a high-speed serial bus that implementswhat Apple calls "virtual slots." (I willtalk about this in greater detailbelow.)

The final difference is actually animportant limitation of the Macin-tosh: it allows only one major ap-plication program to be active at atime (the Mac BASIC and "desk ac-

Memory Hardware OptionsAt a Glance 128K bytes of RAM. 64K bytes of ROM Second disk drive, keypad, ImagewriterStandard Configuration printer, security kit (for chaining com-

Name Main unit with 128K bytes of RAM, 64K puter to table)Macintosh bytes of ROM, integral Sony 3½-inch Software Options

disk drive, 9-inch video monitor, two Mac Paint (drawing program), Mac WriteManufacturer serial ports; external mechanical mouse: (a si mple word processor), Mac BASIC,Apple Computer external keyboard Mac Pascal, others (see text)20525 Mariani Ave. Mass Storage PricesCupertino, CA 95014 One Sony 3½-inch disk drive; 3½-inch Standard system, S1995-S2495 : Mac Paint(408) 996-1010 disk holds 400K bytes and is encased in and Mac Write (together), bundled at no

a rigid plastic housing charge for the first 100 days, S195 (for theDimensions Video Display two) thereafter; Macintosh Pascal, BASIC,9.75 by 9.75 by 13.5 inches 9-inch monitor, noninterlaced 60.15-Hz Logo. Terminai, and Assembler/Debugger,Weight image, 512- by 342-pixel resolution S99 each; Mac Draw and Mac Project,Main unit. keyboard and mouse—22.7 Pointing Device $125 each; keypad, S99; second diskIbs Mechanical mouse drive, $395: Imagewriter printer, $495Power Requirements Keyboard105-130 V AC, 60 Hz (U.S. model); Detached keyboard; 58 keys (59 in inter-85-135 V AC, 50/60 Hz (international national version); autorepeat; two-keymodel) rollover

February 1984 BYTE Publications Inc. 31

Macintosh System ArchitectureInside the Macintosh, hardware and

software work together to provide a systemcapable of supporting high-performancegraphics, built-in peripherals, and commu-nication channels to the outside world.From the beginning of the Macintosh pro-ject, the product-design goals of small size,light weight, and moderate end-user costencouraged us to create a low-power, lowcomponent-count design. The large num-ber of I/O devices that are built into eachunit, combined with our desire for highperformance, caused us to explore manyalternatives for each aspect of the hardwareimplementation. A cooperative spiritamong the people working on the in-dustrial design, analog electronics, digitalelectronics, and low-level software resultedin the synthesis of detailed implementa-tions that combined strengths from eachgroup, providing an integrated design solu-tion for all aspects of the product.

The heart of the Macintosh digital elec-tronics is the MC68000 processor and itsmemory (both RAM and ROM). In theMacintosh, the data-output lines from thesystem RAM drive a data bus separatefrom that used by the rest of the machine(see figure 2). The RAM is triple-ported;this means that the 68000, screen-display-ing hardware, and sound-output hardwarehave periodic access to the address and databuses, so that the video, the sound, andthe current 68000 task appear to executeconcurrently.

ROM memory connects directly to thesystem data bus and is used by only the68000. Much of the system's time-criticalcode, such as the low-level graphics primi-tives, operating-system routines, and user-interface routines, reside in ROM. Macin-tosh software calls this code through 68000"line 1010 unimplemented" instructions,which get one of approximately 480 ad-dresses from an address table stored in lowmemory; this effectively allows the ROMsubroutines to function as extensions of the68000 instruction set. Since the ROM dataand address buses are used exclusively bythe 68000, ROM is always accessed at thefull processor speed of 7.83 MHz; conse-quently, the ROM can perform as a read-only cache memory.

The 512- by 342-pixel video display ap-

by Burrell C. Smithpears in memory as a linear array of 10,94416-bit words of data, with the most signifi-cant bit representing the pixel farthest left.Each 512-pixel horizontal line consists of32 words of data, with bits shifted out at15.67 MHz (322.68 µs per 512-pixel line)followed by 12 words of horizontal blank-ing (taking 12.25 as). The last memory buscycle ofeach horizontal line is reserved forsound DMA, where a byte of sound datais fetched from the sound buffer and sentto the sound PWM (pulse-width modula-tor) for conversion into an analog level. Theupdate rate of the sound channel is thenequal to the video horizontal rate, or22,254.55 Hz. In the vertical direction,342 active scan lines are followed by a ver-tical retrace and enough inactive horizontal

The product-designgoals of small size,light weight, and

moderate end-user costencouraged us to

create a low-power,low component-count

design.lines to take up the same time as 28 hori-zontal lines, providing a vertical retracetime of 1.258 ms. Although screen-memory accesses may occur at any time,a vertical retrace interrupt is generated atthe falling edge of the vertical sync pulseto allow screen animation to occur com-pletely synchronous to the video beammovement.

Access to RAM is divided into syn-chronous time slots, with the 68000 andvideo circuits sharing alternate word ac-cesses during the live portion of the hori-zontal video-display line and the sound cir-cuits using the video time slot during thelast memory bus cycle of the horizontalline. Although the access to RAM isdivided three ways, the 68000's share ismaximized by giving it access to unusedcycles during horizontal and vertical blank-ing. This way, 68000 access to RAMaverages to a speed of about 6 MHz.

For high-performance sound generation,

a tightly coded routine generates 370samples of sound data and places them intothe sound buffer just after a vertical retraceinterrupt. The 68000 's 32-bit registers areused to control pitch with 24 bits of preci-sion, providing each of four possible voiceswith 16,777,216 possible frequencies. Forsimpler sounds, a timer in the system'sVIA provides a square wave of program-mable pitch. All sounds pass through asoftware-controlled volume adjustmentthat creates approximately 20 decibels oftotal amplitude variation in eight discretesteps.

The Macintosh disk controller is a singleLSI (large-scale integration) componentreferred to as the IWM ("integrated Wozmachine") chip. The device, a one-chip in-tegration of the disk controller originallydesigned by Steve Wozniak for the AppleIt, handles data at 500 kilobits per second.To control the disk drive's motor speed, apulse-width modulator located on thedigital board allows the disk to move at oneof 400 possible disk motor speeds; thePWM is driven from a table in memory ina fashion similar to that of the sound sys-tem. By varying the motor speed, wecreated a more reliable disk drive that putssignificantly more data on the same disk.

The Macintosh communications chip,the Zilog 8530 SCC (serial communica-tions controller), provides synchronous andasynchronous data transmission at up to230.4K bits per second using a self-clocking data format and up to 1 megabitper second using an external clock. TheMacintosh's two serial ports are identical;each provides single-ended or differentialsignaling and multidrop (party-line)capability.

The 6522 VIA (versatile interfaceadapter) rounds out the I/O requirementsof the machine by providing system timers,support for the mouse and keyboard, andgeneral-purpose I/O lines for selectingvarious system functions such as alternatescreen and sound buffers and for com-municating with the system's real-timeclock and parameter memory.

Burrell C. Smith is a member of the AppleMacintosh design team.

3 2 February ½984 © BYTE Publications Inc.

Figures 1a-1h : Working with Mac Paint on the Macintosh computer. See text for details.

February ½984 © BYTE Publications Inc 33

cessory'' programs are two exceptionsthat I'll cover later). This limitation islargely due to the Mac's small mem-ory space and the overall design ofthe software, which assumes that thecurrent program has access to all themachine's memory. This is not as badas it sounds; a single application canuse multiple windows, and materialcan be cut and pasted from one docu-ment to another by storing thematerial to be pasted on a "clipboard"before loading in the second docu-ment (which replaces the first). Still,the absence of hardware slots and theinability to run two applicationssimultaneously are two importantways in which the Macintosh is fun-damentally different from the Lisacomputer.

Photo 2: The Macintosh circuit boards. Photo 2a shows the analog board, while photo 2bshows the digital hoard. These two boards plus the video display, 3½/2-inch disk drive, andhousing make up the main unit; only the keyboard and mouse are needed to make a completeMacintosh system.

Reliability and Low Costthrough Simplicity

Although the Macintosh costsapproximately one-third the price of aLisa, the Mac has much more thanone-third of the Lisa's power. Theidea of reliability through simplicitynot only makes the Macintosh pos-sible at a relatively low price but alsoproduces a machine that has a reli-ability normally associated withmuch simpler computers.

One component of the Mac's sim-plicity is its low chip count—it con-tains about 50 ICs (integrated cir-cuits), which decreases its physicalsize and price and increases its relia-bility. Mac reduces its chip count bycombining the functions of manystandard chips into eight program-mable-logic arrays (PALs).

The Macintosh has only two circuitboards, one that holds all its analogcircuitry and one that holds all itsdigital circuitry (see photos 2a and2b). By partitioning its functions andreducing the number of connectors(by decreasing the number of boardsto be connected), the designers havemade the Mac both more reliable andless expensive. They carried thisphilosophy farther by eliminatinghardware slots; you add peripheralsto a Mac through its two high-speedserial ports.

The Macintosh was designed toreduce (or, in the case of the digitalboard, eliminate) the number of

places in which hardware must befine-tuned during assembly. In somecases, the designers eliminated theneed for adjustment through clevercircuit design, which also meansthere's one less thing to go wrongwith the computer once it is in theowner's hands. In other cases, Appleeliminated fine-tuning by requiring avendor of externally manufacturedsubassemblies to tune the part beforedelivery; for example, the video-dis-play tube and yoke are delivered pre-adjusted, and the Sony 3 ½/2-inch diskdrive is delivered tested and withseveral Apple-specified modifica-tions.

Maximum Synergy betweenHardware and Software

The Macintosh's hardware andsoftware were optimized for maxi-mum performance. This means thatthe hardware and software evolvedover a period of time in a process of

mutual give and take. For example,the pixels displayed on the Mac'svideo display are square (not rec-tangular, as in other computers); thisgreatly simplifies the software thatdraws squares and circles, scales textand graphics, and prints screenimages.

Going for theWorld Market

Having learned from past experience,Apple designed the Macintosh so that itcould easily be modified for all markets out-side the United States. The following ex-amples show how pervasive nation- or lan-guage-specific aspects of a computer designare and how Apple has minimized thechanges needed.

•Except for the word 'Apple" on the rearpanel, the Macintosh has no English text

34 February 1984 BYTE Publications Inc

HardwareThe main unit of the Macintosh

consists of eight parts: two circuitboards, a cable to connect them, ametal chassis, a 3½-inch disk drive,a video-display tube with yoke, anda plastic front bezel and rear housing(see photos 3a and 3b). An external

mouse and keyboard make for a totalof 10 parts. The main unit takes upan amazingly small 10-inch by 10-inch area (it is 13 ½ inches high).True, the keyboard and mouse takeup more area than that, but the foot-print of the main unit is considerablysmaller than that of comparable com -

puters. The Mac is also pleasantlycompact and light; an entire Mac sys-tem in an optional padded satchelweighs 25.6 pounds (less than manytransportable computers) and can becarried onto an airplane.

Figure 2 shows a block diagram ofthe Macintosh hardware; for moredetails, see the "Macintosh SystemArchitecture" text box. For now, let'slook at the machine's major subas-semblies:

Processor: The Macintosh uses aMotorola 68000 processor running at7.83 MHz.

Video display: The Mac has a9-inch monitor that displays a non-interlaced image at 60.15 Hz. The res-olution of the video image is 80 pixelsper inch, so the overall screen is 512by 342 pixels.

ROM: The Mac uses two 256K-bitROMs configured as 64K bytes ofmemory. The ROM (read-onlymemory) contains most of the Mac'soperating system and a "toolbox" ofoptimized 68000 user interface relatedroutines (see the text box "The UserInterface Toolbox" for more detail).The ROM is always accessed at fullspeed, 7.83 MHz.

RAM: The Mac has 128K bytes ofmemory; at some point (Apple saysby the end of 1984), this will be ex-pandable to 512K bytes (by substi-tuting 256K-bit dynamic RAM(random-access read/write memory)chips for the 64K-bit chips currentlybeing used). The screen display uses21,888 bytes and is drawn using thismemory and DMA (direct memoryaccess) circuitry. Apple has an un-

Text continued on page 39

anywhere on the product or in the ROM.Each plug is labeled with a picture thatidentifies its function.•The video-display rate of 60.15 Hz is gen-erated internally instead of being derivedfrom the line current. This allows the Macto be used without modification in coun-tries that have 50-Hz line current.•Macintosh software has been designed sothat all text messages, message layouts,and icons can be stored in a resource file,separate from the program itself. A de-signer can use a resource-editor programto change text (for example, to another lan-guage), icons, message layout, and the for-

mats of time, dates, numbers, and curren-cy. With this method, the program itselfdoes not have to be changed and recompiledto make these changes.•The keys on the keyboard are defined bythe software, thus allowing Apple tochange the keyboard easily to accommodatethe special characters needed by some lan-guages. In addition, Apple has designedthe Mac so that two keyboards (differingin only one key) can be used for all ver-sions of the product; Apple customizes akeyboard for a given language by printingthe necessary legends into the plastic keys.In addition, any Mac keyboard can produce

the full Macintosh character set; the onlyadvantage to having the keyboard for a cer-tain language is that the keyboard layoutwill be more appropriate for that language.

With these innovations, the most time-consuming part of modifying the Macin-tosh for another country is translating andprinting the documentation. Apple reportsthat it will be shipping the Macintosh toseveral foreign countries "within severalmonths of the Mac's introduction." (Com-panies never seem to meet such deadlines,so expect foreign versions to be shipped be-fore the end of 1984.)

February 1984 © BYTE Publications Inc. 35

Figure 2: A block diagram of the Macintosh hardware. For more details, see the "Macintosh System Architecture" text box.

36 February 1984 © BYTE Publications Inc.

The User-Interface Toolbox

The latter ability is needed to correctlydisplay window contents when one win-dow overlaps others. The source code forQuickdraw is identical in both the Lisa andthe Macintosh.•Event Manager: All system events (e.g.,keypresses and mouse button presses) arereceived and interpreted through this unit,which mediates between the applicationprogram and the outside world.•Toolbox Utilities: These routines han-dle miscellaneous tasks that include stringoperations, fixed-point arithmetic, and bit-wise logical operations.•Window Manager: Since all action onthe Macintosh display occurs within win-dows, this is a very important unit thatis used a lot. The Window Manager allowsthe application program to interact withwindows on a high level while it takes careof the low-level details automatically. Itallows you to create different kinds ofboxes(document, dialogue, and alert boxes, forexample), delete them, move them, changetheir size, and make an inactive windowactive and vice versa. The WindowManager ensures that the computer auto-matically redraws the necessary screenareas when some aspect of a window ischanged.•Control Manager: This unit controlsthe use of software buttons, check boxes,and dials, all of which can be called on toshow and alter the status of certainvariables.•Menu Manager: Given a two-dimen-sional matrix of menu items (each columnis a menu title followed by its selections),this unit controls the display and behaviorof that matrix of pull-down menus.•Text Edit: These routines control ele-mentary text entry and editing. Text Editis designed with lots of software "hooks"so that you can modify its behavior but stilluse it. An external unit called Core Edit,which must be loaded into RAM, containsmore sophisticated entry and editingroutines; Core Edit can handle differentfonts, sizes, and text styles.

•Dialog Manager: Dialogue boxes aretext boxes with several check boxes; usually,clicking the mouse button near a box selectsit (and the action or condition associatedwith it) and unselects the previouslychecked box. An alert box (as in figure h)alerts you to a potentially dangerous situa-tion and forces you to click on one of twobuttons, "Cancel" or "OK." The DialogManager handles the display of and userresponse to a dialogue or alert box.•Desk Manager: This unit allows theapplication program to use the desk ac-cessories, which are resources that arecalled in from disk if they are not current-ly in memory.

Applications can be written in MacBASIC, Mac Pascal, or 68000 assemblylanguage (usually one of the latter two).Both Mac Pascal and Mac BASIC aredesigned so that their keywords directly callmost of the toolbox routines. Most applica-tions that use the routines are essentiallyan endlessly repeating loop that waits foran event, determines what kind of eventit is, and then processes the event.

The toolbox (which occupies two-thirdsof the high-speed 64K byte ROM inside theMacintosh) includes optimized 68000machine-language routines that handle allaspects of the Macintosh user interface—things like windows, text, the mouse, pull-down menus, desk accessories, dialogueboxes, and fonts. The figure below showsthe relative relationships among the dif-ferent units (or packages of routines). Hereis a brief description of each unit, startingwith the lowest-level unit and working up:

•Resource Manager: These routinescoordinate the use of resources, which aredata structures such as text strings,menus, and icon and font definitions.These resources are kept separate from theactual code of an application, which meansthat the resources of an application can bemodified without forcing a recompilation(or modification) of the application pro-gram. The Resource Manager is usuallycalled by higher units like the menu andfont managers.•Font Manager: This unit supports theuse of various text fonts. It calls theresource manager when it needs to use afont not already in memory, and it is usual-ly called by the Quickdraw unit.•Quickdraw: Quickdraw is a graphicspackage that is at the heart ofboth the Lisaand Macintosh computers. Bill Atkinson,its creator, worked for 3½ years on thecode, rewriting it many times and reduc-ing it from a 160K-byte compiled Pascalprogram to a 24K-byte package of highlyoptimized 68000 code. Atkinson, who wasinvolved in the early design of the Lisa'suser interface, designed and optimizedQuickdraw for the Lisa computer; he laterjoined the Macintosh design team. Quick-draw is very fast—for example, it can printto the screen more than 7000 characters persecond. Two of its most interestingcapabilities are its ability to fill in any ar-bitrary shape with a pattern and its abil-ity to "clip" an image to correspond to theboundaries of an arbitrary masking shape.

February 1984 © BYTE Publications Inc. 37

Macintosh System Software Overviewby Andy Hertzfeld

tine, making each one as efficient as pos-sible, knowing that our efforts would bemultiplied by the millions of units that wewill eventually ship.

It is somewhat risky to put 64K bytesof intricate system software in ROM on adisk-based system, but we did it becausewe wanted the machine to have a built-instandard user interface. By using ourROM-based toolbox, a programmer savesdevelopment time and precious memoryspace; this provides a positive incentive fordoing it our way. Also, the price per bitof ROM is significantly less than that ofRAM, and not having the operatingsystem load in from disk saves space onevery disk you have. Application programsnever reference the ROM directly; instead,they use compact "trap" instructions thatare interpreted by the system dispatcher.This allows us to intercept any routine tofix the program bugs that will inevitablyarise.

The Mac's system software design phi-losophy emphasizes simplicity, flexibility,and high performance. We chose the single-application-at-a-time philosophy to helpkeep things relatively simple. The user-

interface software is designed to be flexiblebecause we are still learning how to makesystems easier and more fun to use.Another reason for designing the softwarethis way is that trying to live for yearswith what we thought was best at anygiven time would doom us to eventualfailure. High performance is extremely im-portant in an interactive system; peoplewon't enjoy using a system unless it is veryresponsive.

About one-third of the ROM is devotedto what we call the Macintosh OperatingSystem, which contains many componentsfound in more traditional systems. It in-cludes the low-level device drivers and in-terrupt handlers, an asynchronous I/Osystem, a memory manager, a simple, fastfile system, a segment loader, and variousutility routines. The I/O system supportsswappable, RAM-based device drivers aswell as its built-in serial, disk, and sounddrivers. Most I/O and file-system calls canbe made asynchronously, which allows anapplication to overlap I/O tasks with othertasks. The memory manager minimizes thefragmentation of available memory intosmall pieces by supporting relocatable ob-jects that are always accessed indirectly;the memory manager also provides anautomatic caching scheme by optionally

The Macintosh is more than a power-ful, inexpensive 68000-based desktop com-puter. It comes with a built-in personalityprovided by 64K bytes of handcrafted sys-tem software contained in two ROM chipson its digital board. Besides performingtraditional operating-system functions suchas memory and file management, the Mac-intosh ROM includes the revolutionaryQuickdraw package and a User-InterfaceToolbox to help programmers develop ap-plications that share a consistent, advanceduser interface.

The Macintosh ROM can be thought ofas an extension to the 68000 instructionset, augmenting its 56 basic instructionswith more than 480 new instructionsdesigned for implementing fast mouse-based applications. It is implemented en-tirely in 68000 assembly-language codethat has been handcrafted and optimizedover a period of almost three years. Wechose assembly language over a higher-level language because it was very impor-tant for the system to be small and fast.The Macintosh is intended to be a veryhigh-volume product, and we could affordto lavish time and attention on every rou-

Photo 3: Inside the Macintosh computer. From the front (photo 3a), you can see the video display and the 3½-inch disk drive. From therear (photo 3b), you can see the two main circuit boards (right and bottom), the rear of the video-display tube, the 3½-inch disk drive, anda row of connectors at the bottom of the unit. The connections go, from left to right, to the mouse, a second disk drive, two peripherals (theseare two serial ports), and an external amplifier (for sound output).

38 February 1984 © BYTE Publications Inc.

purging objects as memory grows fuller.The file system ensures against loss of databy maintaining tags on every block; theseallow the contents of a disk to be pieced backtogether even if the directory is destroyed.

Another third of the ROM is occupiedby Bill Atkinson's Quickdraw graphicspackage. Quickdraw, which is the corner-stone of Apple's "Lisa technology," isresponsible for the Mac's extremely fastuser interaction. It draws practically every-thing you see on the screen, including text(in a variety of typefaces and styles) andboth filled and unfilled rectangles, lines,and ovals. It also is capable of representingarbitrary areas of the screen called regionsin a very compact data structure. AllQuickdraw calls are clipped to the intersec-tion of up to three regions, providing thefundamental capability necessary for over-lapping windows. Quickdraw also is cap-able of recording any sequence of procedurecalls and saving them as a picture. Pic-tures provide an easy, powerful method fortransferring graphics between applications.

The final third of the Macintosh ROMis occupied by the User-Interface Toolbox,a collection of various managers and serv-ices intended to help a programmer developapplications that conform to the Macintoshstandard user interface. Its principal com -

ponents are resources, windows, menus,controls, dialogues, and a text-editingpackage. The window, menu, and controlmanagers contain little information on howindividual windows, menus, or controlslook or behave. Instead, this informationis encapsulated in definition functions,which are kept as resources and swappedinto memory as necessary to implementmessages sent by the various managers.This provides a very flexible structurecapable of evolving as we learn how to im-prove the user interface.

Another important goal of the Macin-tosh system software is to facilitate thepassing of data between applications. Ascrap manager is provided to help ap-plications share data. It defines two datatypes that every application is requested tosupport (simple ASCII text and Quickdrawpictures) and lets applications define theirown custom types. It provides routines fortransferring data in and out of the scrap.

As stated above, Macintosh supportsonly one application running at any giventime. This restriction is mainly due tolimited available memory. By making a fewsimple calls to the desk manager, an ap-plication may allow many useful mini-applications to run concurrently withitself. These small programs are called

desk accessories and are capable of cut-ting and pasting data with each other aswell as with the major application. We cur-rently provide five desk accessories (calcu-lator, clock, notepad, control panel fordefault system parameters, and scrapbook).

By the spring of 1983, it became apparentthat we would not be able to fit all theroutines that we had hoped to into our64K-byte ROM space. We designed a facil-ity to allow some system code (in thesystem resource file) to be swapped in fromdisk to RAM when needed. We now usefive such RAM-based packages, includinga fully IEEE-standard floating-pointnumeric package, a standard file dialoguepackage, and an international stringpackage that deals with various formats fordate and time display.

In summary, the 64K bytes of ROM-based firmware provide Macintosh with aunique personality and user interface,forming the foundation for the developmentofcommunicating applications that sharea common user interface. The Macintoshfirmware is very fast and flexible, and itwill be exciting to see all the applicationsthat develop from it in the years to come.

Andy Hertzfeld is a member of the AppleMacintosh design team.

Text continued from page .35:

disclosed proprietary technique forphase-locking the 68000 to less ex-pensive memory, which lowers theproduct cost without sacrificing thespeed of memory access.

When the Mac is drawing a hori-zontal line of the video display, the68000 and the video DMA circuitryalternate (interleave) their accesses tothe RAM address and data lines.Since these two can never access RAMsimultaneously, the 68000 can neverproduce hashing or other glitches inthe video display by accessing RAMat the wrong time. Because of thisinterleaving, the 68000 accesses RAMat 3.92 MHz, half of the full 7.83 MHzrate, during the display of a hori-zontal line of the screen. This is donein the following way: the DMA cir-cuitry puts a word from RAM intothe video shift register; while theregister is sending out those 16 bitsserially to the screen, the 68000 usesRAM for its own purposes; then thecycle begins again with the DMAcircuitry.

When the video display is doing ahorizontal or vertical retrace, how-ever, the 68000 gets exclusive use ofthe RAM at its full speed, 7.83 MHz.This has a significant effect on theaverage speed of RAM access. Out ofthe 45

µs

(microseconds) for eachhorizontal display line, over 12 µs(about 27 percent of the time) are oc-cupied by horizontal retrace. Of these12 µs, about 0.5 µs is used to senddata to the sound and disk-speed cir-cuitry, while the rest is available tothe 68000. Furthermore, out of the16.626 ms (milliseconds) used to draweach complete screen, 1.258 ms(about 7.6 percent of the time) aredevoted to vertical retrace. Of this,about 14 µs are used for sound anddisk-speed control (representing thecontrol work done at the end of theequivalent of 28 unused horizontallines of video), leaving more than1.244 ms for the 68000 to access RAMat full speed.

To summarize, the ROM is alwaysaccessed at 7.83 MHz, regardless of

screen display. The RAM is accessedat 3.92 MHz during screen displayand at 7.83 MHz otherwise. Theaverage speed of the system isaround 6 MHz.

One memory area of interest is thesound buffer. Along with associatedhardware, this buffer enables you tocreate four channels of arbitrarysound while using no more than 50percent of the 68000's computingpower. The 68000 performs look-upoperations every 44 µs on up to four256-byte waveform tables; the resultof these lookups is placed in a370-byte sound buffer, from whichthe sound hardware fetches 1 byteevery 44 µs to deliver to an 8-bitdigital-to-analog circuit (DAC). An in-ternal VIA (versatile interfaceadapter) can also be used to generatea single square-wave tone whileusing an insignificant part of the68000 's computing power.

Mass storage: The Macintosh usesa custom version of the Sony 3½-inchdisk and drive (see photo 4). The

February 1984 © BYTE Publications inc. 39

The Macintosh Memory MapThe Macintosh memory map contains

RAM, ROM, and I/O devices that com-municate with the 68000 through specifiedmemory locations. When the Macintosh isturned on (i.e., at boot-up), the 64K-byteROM maps into the first page of memoryand is used to get the system started. Afterboot-up, the positions of RAM and ROMare changed so that the 128K-byte block ofRAM occupies the first two pages ofmemory (see figure below).

The Phase Read area of memory is usedto determine whether the computer'stiming signals are correctly in phase witheach other; this is usually done by ROMroutines at boot-up.

The VIA (versatile interface adapter)locations are used by the Macintosh's 6522VIA. This chip gives the Macintoshparallel input, output, and interrupt lines,shift registers, mouse information, andclocks.

The IWM locations are used by theMacintosh's IWM (integrated Woz ma-chine), which controls all access to the in-ternal 3½-inch disk drive and the optionalexternal one.

The SCC Read and SCC Write locationsare used for several purposes. They allowthe SCC (serial communications controller)chip to handle two serial ports at rates be-tween 30 and 230,400 bits per second. In

addition, they allow the SCC to detectmouse motion (in conjunction with theVIA) and adjust the phase of the Macin-tosh timing signals.

Most programmers will not need in-timate knowledge of the Macintoshmemory map. The 64K-byte ROM containssophisticated routines that take care of low-level processes like I/O, memory manage-ment, video display, and similar tasks. Ap-ple encourages the use of these routines;they mean less development time, con-formity to the standard Macintosh user in-terface, faster programs (ROM always runsat full speed), and more memory space forprograms and disks.

40 February 1984 C BYTE Publications I nc

Photo 4: The Sony 3½-inch disk is encased in a rigid plastic housing, and the oval windowthrough which the magnetic medium is accessed is protected by a metal shutter that slidesout of the way when the disk is inserted in the drive. These factors help protect the disk fromcasual use.

drive can store 400K bytes on asingle-sided 3 ½/2-inch disk; the Mac isdesigned to be able to use double-sided drives to get 800K bytes perdisk, an option that Apple may pur-sue at a later date. The standard Sony3½-inch disk (used to date by Hew-lett-Packard and other vendors) puts

70 tracks of data at 135 tpi (tracks perinch) onto each disk. At Apple's urg-ing, Sony now makes the drive inanother model that has 80 tracks ofdata at 135 tpi. As a comparison, theHewlett-Packard HP 150 uses the70-track version and conventionalsectoring to get 270K bytes per single-sided disk.

In addition to the change to 80 tpi,Apple contracted Sony to modify thedrive in several other ways. Twochanges allow the Sony drive tomimic the behavior of the Lisa"twiggy" drives (which were original-ly chosen for use in the Mac): diskejection under software control andvariable disk-rotation speed. The firstchange allows the Mac to ensure thata disk is correctly updated before itis surrendered to the user (that is,you can't take a disk out of the driveuntil the Mac software permits it).The second change enables the Macto record onto the disk at a constantlinear density (which means you canput more data on the outermosttracks), as opposed to the constantradial density approach most com-puters use (which puts the sameamount of data on each track regard-less of position).

The Macintosh 's drive rotatesunder software control between 390and 600 rpm (revolutions per minute)and transfers data at the rate of489.6K bits per second (bits as re-corded on the disk, not decoded databits). Most computers use a disk-controller chip instead of the pro-cessor to control the drive. The Mac(like the Apple II) uses its processorto directly control the drive. Becausethe Macintosh can control more disk-related parameters than the Apple II(the variable motor speed, for exam-ple), Macintosh owners will betreated to an even greater wealth ofcopy-protection schemes than AppleII owners enjoy. Also, the Macintoshdrive uses modified group code record-ing to encode data onto the disk. Thistechnique, invented by Steve Woz-niak for use with the Apple II, en-codes 6 bits of data into an eight-transition group that is recorded ontothe disk surface.

Keyboard: The keyboard has 58keys; the left Shift key is split on theinternational version of the Macin-tosh, giving it a total of 59 keys. Thekeyboard includes Return, CapsLock, and Shift keys in their usualplaces, two Option keys, and acloverleaf command key (see photo5). Combinations of the Shift, CapsLock, and Option keys give each keyup to six meanings; the command key

Sharing Data among ProgramsMacintosh programs, if they are de-

signed in accordance with Apple guide-lines, will be able to trade data amongthemselves without one program havingto know anything about the nature of theothers. This is done through use of ashared memory area called the clipboardand the standardization of the data that canbe stored in it.

The clipboard is a relocatable piece ofmemory that is not erased when a new pro-gram replaces an older one. It is used asfollows: the first program copies data intothe clipboard, the second program replacesthe first with its own code and data, andthe data in the clipboard is added to thedata now in memory. The clipboard cancontain a variable number of data items,though every item must be of a differenttype. Each data item consists of a four-character data-type identifier, a 32-bitlength (in bytes), and a stream of bytes that

makes up the actual contents of the dataitem.

Programs are free to implement theirown data types. Apple has defined two—text and Quickdraw pictures—and en-courages every program to be able to readboth and write at least one of these datatypes. Text is a simple ASCII string ofcharacters without any information on thesize, font, or position of the text. Quick-draw pictures are defined as a sequence ofcommands that can be understood by theQuickdraw routines. A Quickdraw picturecan contain displayable text (which doesinclude information on text size, font, andposition on the screen), a sequence ofelementary graphics commands that willrecreate the image, or the image describedas a stream of bits. These two data typesprovide a guaranteed means of communica-tion among Macintosh programs.

42 February BYTE Publications Inc.

acts as a modifier and is often usedwith a letter key as the keyboard sub-stitute for a mouse-selected menuitem. The keyboard contains an 8021microprocessor and is connected tothe main box by a four-wire bidirec-tional serial connection. The connec-tions on both ends use the same kindof square modular plug found inmost telephones.

Mouse: The Mac 's one-buttonmechanical mouse, about the size ofa pack of cigarettes, is essentially thesame as the Lisa's; it differs only inthe shape of the plastic housing. Themouse is used to position the cursoron the screen; when you slide themouse over a horizontal surface, thecursor moves in the same directionon the screen.

Serial bus: The Macintosh's serialbus is very important because it is theway that most future peripherals (ex-cept the second 3'/2-inch disk driveand the keypad) will connect to thecomputer. The bus can run in twomodes: with an external clock, it cantransfer data at up to 1 megabit persecond; with internal clocking (whichembeds clock bits in the data streamitself), it can transfer data at up to230.4K bits per second. The latter

scheme will be used to connect mostperipherals, which need only a lowto medium data-transfer rate, to theMacintosh in a passive daisy-chainedline. This scheme implements whatthe Mac's designers call "virtualslots."

Virtual slots have several advan-tages over conventional hardwareperipheral slots. They reduce thepotential problems inherent in anyadded mechanical connection (aserial interface connector has fewerpins than a typical interface board).They reduce RFI (radio-frequency in-terference) by keeping the main boxleakproof and allowing easy, inex-pensive shielding of the serial line.By deciding that peripherals willsupply their own power, the Macin-tosh designers were able to stream-line the power supply of the mainbox without worrying about thepower needs of unspecified futureperipherals. Finally, virtual slotseliminate the need of peripheralcards to insert themselves some-where in the computer's memorymap; the unchanging memory mapcreates a known, unchanging systemarchitecture that all software design-ers can be assured of, regardless of

the peripherals connected.The virtual-slot scheme is both

practical and elegant; it offers asimple, standard way to connect un-specified future peripherals. The230.4K bit-per-second data-transferrate is high enough to meet the needsof most peripherals—printers,modems, plotters, music synthe-sizers, and so on. However, one classof add-on card will not work usingthis scheme: processor cards like theMicrosoft Softcard, which allow acomputer to run another processor'ssoftware. Such cards require full ac-cess to the data and address lines andwill not work via a serial "virtualslot." As a result, despite somerumors to the contrary, the Macin-tosh will never use IBM PC- or MS-DOS-based software.

Power supply: Apple designed twopower supplies for the Macintosh.The first one uses a 60-watt switch-ing power supply similar to one usedin the Apple II family; it can operateon 85 to 135 V AC at either 50 or 60Hz. For technical reasons, use of thispower supply would have delayedthe introduction of the machine, soApple designed and produced asimpler nonswitching power supply

Photo 5: The Macintosh keyboard.

February 1984 BYTE Publications Inc. 4 3

(105 to 130 V AC, 60 Hz) for initial usein the first U.S. models of the Macin-tosh. The first switching power sup-ply will be used later in the year forthe international model and possiblyfor the U.S. model.

The supply was designed to drivetwo twiggy disks; when the designwas changed to include two 3½-inchdisks instead, the supply had asizable margin of unused power.

System SoftwareAs stated before, the Macintosh

contains 64K bytes of ROM accessed

at 7.83 MHz. The ROM contains mostof the Mac operating system and a setof optimized 68000 routines calledthe Macintosh User-Interface Tool-box. The operating-system softwareinteracts at the lowest level with thehardware; it includes such things asdevice drivers and memory- and file-management routines. The toolboxcontains various routines that let youmanipulate windows, text, themouse, pull-down menus, desk ac-cessories, dialogue boxes, fonts, andother aspects of the Mac user inter-face. These are high-level routines

that perform the details of such com-plicated operations with minimumprogramming on the application de-signer's part. For example, thewindow-management routines takecare of correctly redrawing the dis-play when a window is moved orchanged. For more details, see thetext box "The User-Interface Toolbox."

The designers intend for you to ac-cess all ROM routines indirectly viathe 68000 "line 1010 unimplemented"instructions, which receive their ad-dresses from a table in RAM; thistable can be changed to point to otherroutines, thereby allowing future ver-sions of Mac software to patch the in-evitable bugs that will be found in theMac ROM. Because the applicationdrives the ROM routines (instead ofthe other way around), the Macin-tosh is an "open" system whosebehavior is completely determined bythe contents of the disk inserted intoit—that is, software designers can usethe ROM routines to create a "stan-dard" Macintosh application, or theycan write their own code to create anapplication that behaves the way theywant it to.

Although the designers of theMacintosh have a general philosophyof allowing only one application pro-gram to be open at a time, they haveincluded in the main menu a collec-tion of short, useful programs thatcan run without forcing you to endyour current program. Apple callsthese programs desk accessories. Manyof the accessories are simply con-veniences—the clock accessory, forexample, shows you the current dateand time—but a very powerful ac-cessory is called the scrapbook. Or-dinarily, you can cut and paste datafrom one document to another bycutting the data into the clipboard,loading in the new document, andpasting in the data; this processwould be tedious if you had severalitems of the same type to cut andpaste. The scrapbook is a sequenceof data items—text or graphics—thatcan be stored or recalled together,thus minimizing the number ofdocument changes and allowing youto recall often-used data items easily.The scrapbook is actually imple-mented as a disk file; as a result, it

44 February 1984 C BYTE Publications Inc. Circle 327 on inquiry card.

tends to be rather large.System software reacts to all pe-

ripherals on an asynchronous basis—peripherals compete for the attentionof the 68000 by sending it interrupts,which the 68000 services according tothe level of the interrupt. This keepsthe 68000 from being tied exclusivelyto a peripheral—for example, to the3½-inch disk drive waiting to get upto its full speed—when it could bedoing something more useful. TheMac's designers have managed to dothis even with high-speed periph-erals that usually require the full at-tention of a processor. For example,disk and serial-port routines havebeen dovetailed to permit the use ofboth peripherals at the same time.

Disk ReliabilityReliability was one of the main

reasons that Apple decided to usethe 3'/2-inch Sony disk drive insteadof the 5 ½/4-inch twiggy drive. (A pro-jected shortage of twiggy drives wasanother reason.) Apple is expectingthe Macintosh to be the first realconsumer-oriented computer, and it

sees the magnetic medium as beingmore likely to fail than the elec-tronics. The Sony 3½-inch disk is bet-ter suited to the consumer environ-ment. The drive can hold an accept-able amount of storage per disk, andthe small disk, with its rigid shell andnormally closed access window, isless likely to suffer from bad handlingthan a conventional 51/4-inch floppydisk. In addition, the magneticmedium is connected to a steel hubthat the drive mates with and rotates.This is an improvement over51/4-inchfloppy-disk drives, which clamp theMylar edge of the center hole. The3'/2-inch disk hub is needed to get ac-curate enough disk-head placementto make a data density of 135 tracksper inch possible.

The data on the disk is encoded ina way that enables the Macintosh torecover from some disk medium ordisk file errors. The file directory isduplicated in a normal disk file(which can be used if, for somereason, the directory is damaged).Also, each block of data on the diskincludes a 12-byte identifier that gives

the file number, sequence-within-filenumber, and date/time stamp for thedata in the rest of that block; this canbe used in many situations to recovermost or all of the data on the disk.

Applications and LanguagesNeither application software nor a

language is included in the basicMacintosh package. However, a two-program set will be available for $195;both programs require the recentlyintroduced Imagewriter printer toprint things out. The first program isMac Paint, the drawing program welooked at earlier. Created in house atApple, Mac Paint is limited to draw-ings that will fit on one 81/2- by11-inch page. Mac Paint is unlike theLisa drawing program (Lisa Draw) inthat it manipulates the drawing on abit-by-bit level (a Lisa Draw drawingis stored as a collection of elementaryobjects—circles, text, boxes, etc.). Thisrepresentation makes some things,such as arbitrary erasures, easier onthe Mac and other things, such as de-leting a single object within the draw-ing, harder.

46 February 1984 C BYTE Publications lnc -

Figure 3: The Mac Write word-processing program.

The second program in the set isMac Write (figure 3), which wascreated out of house for Apple andcan handle documents up to 10single-spaced or 20 double-spacedpages. Like Lisa Write, Mac Write canhandle multiple fonts and sizes aswell as variations achieved by addingany combination of five modifiers—underline, bold, italic, outline, andshadow.

Apple Macintosh Pascal, Assem-bler/Debugger, BASIC, and Logo willcost $99 each; the first two will beavailable during the second quarterof 1984, and the other two will followin the third quarter. The Logo is fromLCSI, which developed Apple IILogo. Both the BASIC and Pascalcompile on a line-by-line basis into anintermediate pseudocode, whichgives them the speed of compiledlanguages while retaining the interac-tive nature of interpreted languages.Both languages use separate win-dows for program source code andoutput, and both can be debugged

on a line-by-line basis. Both havegraphics and mouse commands thatcall on the toolbox routines in ROM,and both use floating-point arith-metic routines (in RAM) that meetthe IEEE 754 floating-point standard.

Mac Pascal, which was created outof house, is interesting in that it is theonly Pascal I know of that can be ex-ecuted interactively. Another nicefeature is its syntax checker, an itemthat can be called from its "Run"menu. This menu item is oftenhandy for finding those petty syntaxerrors to which Pascal code is prone.

Mac BASIC was created in houseby Donn Denman, who worked onApple III Business BASIC. An inter-active, multitasking BASIC, it can ex-ecute multiple copies of the sameprogram or multiple programs simul-taneously; each program and eachrunning task has its own window.

Other Apple programs announcedfor delivery in 1984 include Mac Ter-minal (which emulates the DECVT-52 and VT-100 and Teletype ASR33

terminals—available first quarter,$99). Also planned are Mac Draw (anobject-oriented drawing program)and Mac Project (a scheduling andproject-management program).These are both Macintosh versions oftwo Lisa application programs; eachcosts $125 and will be available in thethird quarter of 1984.

Third-Party SoftwareApple has not spent all its energy

trying to write all the software thatthe Macintosh needs. Instead, it hascreated two exemplary Macintoshpackages and gone to third-partysoftware developers to get them tocreate the bulk of available Macintoshsoftware. Apple estimates that by thetime you read this, the Mac will bein the hands of more than 100 soft-ware vendors.

At the time this was written, somesoftware developers had made com-mitments to market Macintosh soft-ware. Microsoft Multiplan andBASIC will be available at the Mac's

48 February 1984 C BYTE Publications lnc.

50 February 1984 C BYTE Publications lnc

By the Way. . .•No, we didn't misspell the name. "McIn-tosh" is the apple, but "Macintosh" is theApple computer. The product's originalcode name was misspelled by its first users,and Apple decided to stay with thatspelling.•The Mac Write program was originallynamed "Macauthor," and the Mac Drawprogram was originally named "Mackel -

angelo." People at Apple decided that thenames were too cute to use; they wereright.•Apple is one of those exceptional com-panies that gives its employees credit in-stead of commanding them to work in ano-nymity behind the corporate name. Thenames of the hundred or so employees whoworked on the Macintosh are molded into

the inside face of the plastic rear housing.Don't try to look for them, though; theMac is not supposed to be opened exceptby repair people.•The Macintosh is not going to be strictlya "serious" computer. Some of the softwareengineers at Apple are very excited aboutthe great games that could take advantageof the Mac's computing power and high-resolution graphics. I saw an incrediblegame that has Alice (of Wonderland fame)dodging animated chess pieces in 3D.

introduction; Microsoft File, Chart,and Word will be available by mid-February. Lotus is working on con-verting its popular 1-2-3 spreadsheetprogram. Software Publishing Cor-poration will have its PFS File andPFS Report programs available some-time in April.

Optional HardwareThe Macintosh uses Apple's new

$495 dot-matrix Imagewriter printer,the only printer that is supported bythe current print driver within theMacintosh. To get its level of graphicsand text quality (see listings lathrough lc), the Imagewriter usuallystays in a graphics mode that printsa single column of dots for every bytesent to it by the Mac. However, theImagewriter can print text in threemodes: a high-resolution mode(listing lb), a medium-resolutionmode (listing 1c), and a draft modethat uses the printer's built-in char-acter set for quick text-only printing.(I found I prefer the medium- overthe high-resolution text.) Althoughthe Imagewriter could hardly becalled fast, it is not unacceptablyslow, and it is considerably fasterthan the Apple Dot-Matrix Printerrunning under the Lisa computer'sparallel port.

Two other pieces of hardware arean external disk drive (at $395,available during the first quarter) anda numeric keypad ($99, at introduc-tion). The external disk driver con-nects to the main unit via a dedicated"second disk" connector in back.When the keypad is connected, thekeyboard line runs from the Mac,

through the keypad, and into thekeyboard itself. Another product, an-nounced but not scheduled, is exter-nal hardware that will give the MacIBM 3270 emulation capability.

Documentation and TrainingIn its ads, Apple is stressing the

necessity of going to a Macintoshdealer and trying the computer out.Once you have bought it, though,you will probably be learning how touse the Mac on your own. Apple willhelp you in this process by providingyou with a cassette/disk combination.You boot up the 3½-inch disk tutorialand listen to the interactive lessonprovided on the cassette. (Of course,you have to have a cassette player.)Although I have not seen the cas-sette/disk tutorial program, I think itwill work well; text-only tutorial pro-grams are fine, but many buyers ofthe Mac will benefit from the warmthof a human voice teaching them.

I saw final-draft copies of only twoMacintosh product documents. Ex-plore Mac Paint is a booklet (about 25pages) that teaches you about MacPaint by showing you what it does.It is very easy to read because it hasmore pictures in it than text. MacWrite is much longer and looks morelike conventional documentation. Itis sensibly divided into three sec-tions: "Learning Mac Write" (a do-by-example tutorial that shows you mostof the features of the program),"Using Mac Write" (a "cookbook"showing you how to accomplishmany common tasks), and "Refer-ence." All in all, the documentationshould be quite good.

ServiceThe Macintosh has no user-service-

able parts. Unlike the Lisa computer,the Mac is not meant to be opened bythe user; you are expected to returnyour Mac to an authorized Apple ser-vice center for repair. The Mac comeswith Apple's standard 90-day parts-and-labor warranty. You can also buya one-year maintenance contract. Ac-cording to Apple, other service planswill be available, including optionsfor large-volume purchasers of theMacintosh.

CaveatsI wrote this article after two days of

meetings with various members ofthe Macintosh staff, studying pre-liminary Mac documentation, mak-ing numerous phone calls to Apple,and working for several days (over aperiod of weeks) with a Macintoshcomputer. I used several final-draftversions of Mac Write and Mac Paint,though I occasionally found oper-ating-system features that "crashed"the system or weren't yet imple-mented. Apple was still makingminor changes to both software andpricing when this was written.

CommentaryThere is a lot to like about the

Macintosh; it is a superb example ofwhat American technology can dowhen given the chance. The simple,compact, economical design, the vir-tual slots, and the enhanced perform-ance of 128K bytes of memory be-cause of the 64K-byte ROM code areall important innovations done well.

I'm glad that Apple decided to go

February 1984 1 BYTE Publications Inc. 51

52 February 1984 BYTE Publications lnc.

with a Sony 3 ½ -inch disk (as com-pared to the Lisa 1, which needs spe-cial, expensive, hard-to-get twiggyfloppy disks). However, I'm disap-pointed that both Apple and Hew-lett-Packard have used nonstandardformats that are incompatible witheach other. It would have been niceto start the widespread use of theSony microfloppy with a standarddisk format, but the incentive tosacrifice standardization for perform-ance is one of the drawbacks of acompetitive industry.

I also feel strongly that the basicMacintosh package should includetwo disk drives. With a one-drive sys-tem, it will take at least eight diskswaps to back up a 3½-inch disk.How many people (especially nov-ices) will go to this trouble, and howmany will suffer when they don't? (Iam not alone in feeling this way; thefirst thing two BYTE editors saidwhen they first saw the Macintoshwas, "Only one disk drive? You've gotto be kidding!" After numerous diskswaps when trying to load MacPaint from one disk and a drawingfrom another, I am convinced thatmost users will eventually buy thesecond disk drive.)

At the time this was written, Applewas committed to a totally unbun-dled pricing of the Macintosh—thatis, the basic Macintosh package (at$1995 to $2495) includes the mainunit, the keyboard, the mouse,necessary cables, a tutorial disk, anda disk containing the operating sys-tem. Everything else—Mac Write,Mac Print, all languages, the Image-writer printer, and the second diskdrive—is priced separately. Sincemanufacturers want to claim thelowest possible price for their prod-ucts, unbundling is common (IBM,for example, introduced the IBM PCwith a low-end model, 16K bytes ofmemory, and a cassette port for$1265). True, the low-end Macintoshis far more complete than mostmanufacturers' low-end products,but Apple has taken unbundling far-ther than any other microcomputervendor—no one has sold a computerwithout BASIC (or some other lan-guage) in years.

A usable Macintosh system with

Mac Write, Mac Draw, a program-ming language, and the Imagewriterprinter costs from $2589 to $3189; asecond disk drive will add another$395. Apple would be wise to makethis package available at a dis-counted package price, just as it nowdoes for the Apple Ile. Apple con-tends that the Macintosh will be-come a home machine because officeusers will take it home a few timesand like it enough to buy themselvesone for their personal use. However,the Mac is still too expensive topenetrate the home market signi-ficantly; that will be left to lessexpensive machines, such as theCommodore 64, the IBM PCjr, theApple II family, and the ColecoAdam.

Finally, I have to point out that,although Apple's advertisements callthe Macintosh a 32-bit system, itsMC68000 processor is generally re-garded as a 16-bit processor (thelimiting factor is its inability to dealwith multiplicands greater than 16bits). This is no different from the

vendors of some other 68000-basedmicrocomputers, but I hate to seeApple hyping a machine that easilystands on its own merits.

ConclusionsExactly a year ago, in a product

description of the Apple Lisa com-puter, I said, "Technology, while ex-pensive to create, is much cheaper to

The Macintosh is stilltoo expensive to

penetrate the homemarket significantly;

that will be left to lessexpensive machines.

distribute. Apple knows this machineis expensive and is also not unawarethat most people would be incrediblyinterested in a similar but less expen-sive machine. We'll see what hap-pens"

Now we have seen what has hap-pened, and it is rather impressive.The Lisa computer was important

because it was the first commercialproduct to use the mouse-window-desktop environment. The Macin-tosh is equally important because itmakes that same environment veryaffordable. It is also importantbecause it is a second-generationdesign that, in several areas, im-proves on the original.

The Macintosh will have three im-portant effects. First, like the Lisa, itwill be imitated but not copied. In theyear since the Lisa was announced,dozens of hardware and softwarecompanies have announced productsthat duplicate part of the Lisa userenvironment—the mouse, the win-dows, the integrated software. Some,like Microsoft's mouse-based series ofpackages and Visicorp's Visi On, havetried to mimic that environment ona smaller, less expensive machine(the IBM PC) with only partialsuccess.

In a similar way, companies will beout to imitate the Macintosh, buttheir attempts will be less successful.Those companies that try to imitate

Circle 160 on inquiry card. February 198 4 BYTE Publications Inc. 53

the Mac on other machines will havetrouble matching its price/perform-ance combination. So far, attempts toimitate the Lisa by enhancing an ex-isting computer (usually an IBM PC)have been given the benefit of thedoubt because they are less expensivethan the Lisa; attempts to imitate theMacintosh will now have a hardertime because the Mac with software isabout as cheap as the host hardwarealone.

The only other way to match theMac would be to design an entirely

new system that would be compar-ably priced. This will probably not beattempted; only a few corporationshave the ability to duplicate Apple'sdesign and manufacturing effort, andstill fewer will make such a largefinancial commitment. (Apple is theonly American company that doesnot live under the tyranny of nextquarter's profits; if any company triesto duplicate Apple's effort, it willprobably be a Japanese one.) Thosethat try will find it hard to createsimilar technology that competes

with the Macintosh in size and price;Apple is confident that a number ofits components and manufacturingtechniques will be difficult to copy.Even though Apple has sufferedfrom carbon-copy Apple II machines,it does not expect to have the samething happen with the Macintosh.

Second, the Macintosh will securethe place of the Sony 3½-inch disk asthe magnetic medium of choice forthe next generation of personal com-puters. I was disappointed when Ifirst saw that the Mac used the3½-inch disk—"Another disk formatto contend with;' I thought, "and youcan't use disks from the Lisa." (Youwill be able to use Mac disks with thenew Lisa 2; see 'Apple Announcesthe Lisa 2," on page 84.) Once I hadheard Apple's line of reasoning,though, I had to agree with its choice.Hewlett-Packard's HP 150 is the onlyother major computer to use theSony 3½-inch disk to date; Apple'suse of it will tip the scales in Sony'sfavor, and other manufacturers willfollow.

Third, the Macintosh will increaseApple's reputation in the market; infact, to some people Apple will be assynonymous with the phrase "per-sonal computer" as IBM is synony-mous with "computer." The Mac willcompete with IBM's PC, not itscheaper sibling, the IBM PCjr. Manybusiness users will stay with the"safer" IBM PC. However, peoplenew to computing and those who aremaverick enough to see the value andpromise of the Mac will favor it. TheMac will delay IBM's domination ofthe personal computer market.

Overall, the Macintosh is a very im-portant machine that, in my opinion,replaces the Lisa as the most impor-tant development in computers in thelast five years. The Macintosh bringsus one step closer to the ideal of com-puter as appliance. We're not thereyet—at least, not until the next set ofimprovements (which, in this in-dustry, we may see fairly soon). Whoknows who the next innovator willbe? ■

Gregg Williams is a senior editor at BYTE. Hecan be reached at POB 372, Hancock, NH 03449.

54 February 1984 BYTE Publications Inc.