About the Author

Dan Fylstra is a graduate of Massachusetts Institute of Technology and a second year student in the MBA program of Harvard Business School, cpn­ centrating in marketing. His background includes ext~nsive work with high . level languages including authorship of the. ,PLMI6800! compiler for Inter­ metrics Inc, and consulting on the HA LIS language and compilers for NASA and the European Space Agency. His equipment now includes a KIM-7, (In OSI system, PET 20()J and Radio Shack TRS-,80.

User's Report: The PET 2001

Dan Fylstra About a year ago Commodore Business Now the first PETs have been del ivered, 22 Weitz St #3 Machines Inc, a well-known maker of pocket and a few computer stores have begun Boston MA 02134 calculators, startled everyone in the personal advertising their availability. The PET's computer industry by announcing its PET price has risen to $595, and in the meantime computer, a self-contained unit with key­ other personal computers with comparable Photography by Dan Comly board, display, cassette drive and built-in price and performance characteristics have BASIC for $495 . The announcement was come on the market. Many people are greeted with considerable enthusiasm and wondering which computer represents the skepticism, for Commodore obviously was best buy in terms of hardware and software stretching the state of the art in technology, capabilities, expandability, availability and manufacturing and mass distribution. delivery, warranty and service, and software support. If you are considering purchase of such an "appliance" computer, this review should help you make your own informed judgments on these issues. I ordered a PET a few days after the finished product was shown at the National Computer Conference in Dallas TX last June, and hence I received one of the early units (apparently number 17 off the production line) without a complete user manual describing everything the PET can do. By the time this is printed a better user manual should have been published; so bear in mind that this is a preliminary review, written in late October 1977, and based on experience with my PET, conversations with Commodore engi­ neers at trade shows, and precious little documentation. I have not been able to test some of the PET's many features, in particular the expansion options, due to the dearth of information from Commodore. For a more complete picture, talk to your computer dealer and, if possible, to other PET owners before you make a purchase decision. Photo 7,' A view of the Commodore PET, Model 200 7. This personal com­ puter sells for $595 and includes a keyboard, video display, cassette drive, General Specifications 4 K bytes of programmable memory, and a BASIC interpreter and operating Photo 1 illustrates the attractive overall system in 74 K bytes of read only memory. appearance of the Personal Electronic

114 BYTE Marc h 1978 - PET per-sorral c:.-- ~;.Il Jl J 1 ~ ;>orlt UCl C:OrTJput:;er

,. r P ',I ...... , i 'to , , ) \E:3 ~ ~\8 .' ~ .. " , - 0" 1 1 r , r n - P I i ; B ;; \ ; III• w .. R T V U I 0 1 , J L -l i I I I 1 •5 G • • - - G H K L , . A B 0 F .. \ " x I / . .- .. ~ - 1 2 • • C v a N M , I ? " \, - Z x " ,. -- I "l T JI , ( ~ L \ _ II I!! • ( I 1:11 . 8i9 a

Photo 2: A close-up of the PET keyboard and cassette Transactor, Mode l 2001 (as it is fancifu lly ca lculator chi ps and other sil require­ drive. The keyboard is a ca ll ed). Overall it measures 16.5 inches (4l.9 ments, the PET is based on the MOS Tec h­ flat, calculator style unit cm) wide, 18.5 inches (47 cm) deep and 14 nology 6502 . This may not with 73 keys. The upper inch es (35 .6 cm) high , and weighs 44 pounds be of much significance to the casual user case shift positions on 64 (20 kg). The PET is a lot more portable than since the machine is primarily designed to of the keys are occupied most computers, but you wo n't have to be programmed in BAS IC, but it may make by graphic characters. At carry it very far before you'll appreciate how a difference to the experienced hobby ist the right are the cursor heavy an oddly shaped 44 pound package who intends to write machine or assemb ly control and insert/delete can be. On the other hand, all the essential language programs as well. keys and a numeric peripherals are integrated into the unit, and keypad. al l you need is a wall socket to power up Disp lay Screen and start typing in BAS IC programs. A powerful BAS IC interpreter and an The PET includ es a 9 inch (22.9 cm) en­ presently supporting mu lti­ closed , black and white, high resolution CRT ple external peripherals are bui lt into the disp lay which presents 1000 characters, ar­ PET's 14 K bytes of read only memory. The ranged in 25 Iines of 40 characters each. The PET for $595 includes an additional 4 display is memory mapped (ie: continuously K bytes of progl'ammab le memol'y, which read out of a section of programmable mem­ ho lds your currently running BASIC pro­ ory separate from the BAS IC program and gra m and data. An ex pand ed model for $795 data memory), and is easi ly controlled from includes 8 1< bytes of user memory (the BAS IC using PRINT and POKE statements, maximum amount of memory inside the (PET owners who have not already done so standard cabinet). Thanks to the efficient may want to experiment with dil'ect access, encoding of BAS IC statements (see below), via POKE statements, to the display eve n th e basic 4 K unit ca n hold up to a few memory, wh ich starts at location 32768.) hundred lines of program text. Bui lt-in software provides a winking cur­ Since Commodore had acquired MOS sor and automatic scroll ing from the bottom Technology Inc as a captive source of its of the disp lay. The cursor can also be moved

116 BYTE Maceh 1978 in any direction using the cursor control keys (see the keyboard layout shown in photo 2), and the insert/delete key can be used to "push apart" characters on a line to make room for changes or to delete characters and "close up" the space which they formerly occupied. These features provide a conven ­ ient way to modify a BASIC program without having to retype entire lines: just list the lines on the display, use the cursor control and insert/ delete keys to make changes directly on the display, and press the return key after each line is satisfactorily modified. A key is also provided to clear the screen or to send the cursor to the "home" position (upper left-hand corner).

Character Set The PET's stand ard character set includes Photo 3: A simple example of the PET's graphic capabilities. This display was 64 upper case alphabetic, numeric and special created with a series of 23 BASIC PRINT statements. The graphics characters characters, and 64 graphic characters, which in each character position run together to form the figures. Th e playing card are generated by pressing the shift key and illustrates the use of the reverse field option. one of the regular character keys (see photo 2). Each character is formed on the screen in an 8 by 8 dot matrix, and each character position on the screen is contiguous to those commodore Radio Shack around it, so that graphic characters can be run together to form lines, solid areas and PET TRB-BD other shapes and figures. Furthermore, EITHER WA Y . .. We've got software for you! a "reverse field" feature, applicable on a character by character basis, changes each Show your friends what your computer can do. Learn programming white dot to black and each black dot to techniques the enjoyable way-by playing and modifying these game white. This in effect gives 64 additional programs. Just drop in the cassette and save hours of typing time. All graphic characters. Any of these characters, programs run on 8K PETs and 4K TRS-80s (slightly simplified). including the reverse field and cursor control INTRODUCTORY SPECIAL: Play POKER against your computer. characters, can be inserted into a BASIC Match wits to corner ONE QUEEN on a graphic chessboard. Enrich language PRINT statement, so that inter­ your KINGDOM amid wars, famine, earthquakes, assassinations, etc. esting graphics effects can be created quite Test your bravery as a MATADOR in a bullring. Nearly 1000 lines of easily . A simple example of the PET's BASIC. 33% discount price until March 31 for all four ...... $9.95 graphics capabilities is shown in photo 3. STIMULATING SIMULATIONS by Dr. C. W. Engel: Ten original In general, the PET's graphics capabilities simulation games such as Diamond Thief, Monster Chase, Lost are better adapted for drawing pictures of Treasure and Space Flight, complete with a 64 page illustrated book this sort than for plotting mathematical giving flowcharts, listings and suggested modifications .. . . $14.95 functions. 6502 ASSEMBLER IN BASIC (for PET only): Accepts all standard For the person who is more interested in 6502 instruction mnemonics, pseudo-ops, and addressing modes alphabetic text than in graphics capabilities, plus new TEXT pseudo-op. Evaluates binary, octal, hex, decimal, and the PET provides an upper and lower cas e character constants, symbols and expressions. Uses PET line number character set with a limited number of and cursor editing features for assembler source code. Supports execution of assembled programs with keyboard and display I/O. graphic characters. The lower case option, Fully documented and easily understood and modified ... .. $24.95 wh ich is appl icable to the entire screen at once, is en abled by means of a POKE ORDERS: Check, money order or VISA /Master Charge accepted. We statement wh ich changes the setting of an guarantee you functioning programs, readable cassettes and prompt address line on the character generator delivery. Our catalog, $1 or free with any cassette, fully documents read only memory. The effect is to produce these and other programs and describes our royalty program for software authors. For a FREE flyer, use reader service card, or send a a lower case letter in place of the graph ic self-addressed stamped envelope for faster service. character which normally appears wh en an alphabetic key is pressed in upper case I VISA"~ Personal Software™ • sh ift. (Yes, you must press the sh ift key .1P.o . Box 136-B3, Cambridge, MA 02138 to get lower case, and omit the sh ift key to VISA/MC telephone orders welcome at (617) 783-0694 get upper case!) This is illustrated in photo 4.

118 BYTE Marc h 1978 Circle 93 on inquiry card. Photo 4: An illustration of upper and lower case letters on the PET. 26 of the 64 graphics characters can be exchanged for lower case letters by altering an address line on the char­ acter generator read only memory.

Keyboard Cassette Drive A much criticized feature of the PET is Also built into the PET's cabinet is an the design of the keyboard itself. It is a audio cassette recorder, which can be used calculator style keyboard rather than a true for saving and loading programs and data. typewriter keyboard . The keys are small This device is hand operated much like an and flat (about a half inch square and a ordinary cassette recorder, but the motor quarter inch deep). They are tightly packed can be started and stopped under software next to each other and are arranged in verti­ control, and the state of the manual switches cal rows rather than the slanting rows used can be sensed to a limited extent by soft­ on a typewriter keyboard. Although the ware (yet the PET will still try to save a pro­ alphabet follows the usual typewriter layout, gram on cassette if you've pushed PLAY the PET keyboard really cannot be used for instead of PLAY and RECORD). The cas­ touch typing because of the size, depth and sette drive is said to be "modified by spacing of the keys. The keyboard is said Commodore for much higher reliability to be reliable and long lasting, but I did find of recording and record retention." The that the space bar would not register correctly exact recording method used by the PET is unless it was pressed squarely in the middle. not yet documented, but it appears to Certainly the keyboard lowers the cost of operate at a speed in the range of 1000 to the unit somewhat, and Commodore points 1400 bits per second. Because all informa­ out that their keyboard provides a larger tion is recorded redundantly, the effective number of keys and hence more graphic data transfer rate is about half this much . characters, but it is definitely more difficult But the redundant recording enables the to use. As a result many PET to detect and correct many recording users may try to interface a separate type­ errors. In my experience, data storage on the writer style ASCII keyboard to the PET. PET cassette drive has been remarkably re­ A BASIC program can obtain input of liable and trouble free. numeric quantities and character strings from the keyboard using an INPUT statement. Operating System But Commodore BASIC also includes a GET An elegant cassette operating system statement, which allows the program to cap­ in the built-in read only memory supports ture each key from the keyboard as it is named tape files of both programs and pressed without the scanning, editing and data, with file names up to 80 characters conversion normally performed by the long. A SAVE command writes a program BAStC system on input. This feature makes onto a tape cassette, and the thoughtfully it easy to implement interactive keyboard provided VERIFY command can then games. be used to reread the program from cas-

120 BYTE March 1978 sette and compare it to the program still capable of handling multiple cassette drives in memory to verify that it was written and apparently other peripheral devices successfully. This is an essential feature as well . A second cassette drive interface when dealing with audio cassettes, if only is in fact included in the basic PET. for the user's peace of mind. A LOAD command will search down the tape for a Commodore BASIC named program and then load it into Table 1 summarizes the features of the memory. Similarly, a data file, written on powerful BASIC interpreter built into the tape from BASIC by means of OPEN, PET Commodme BASIC, develop ed by the PRINT# and CLOSE statements, can be folks at who brought you Altair searched for and read by another BAS IC BASIC, features real numbers, integers program using OPEN and INPUT# and strings, multidimensional arrays, a full statements. set of mathematical functions, and a variety With a little care, programs can be of extensions for string handling, input and chained together: a program segment in output on external peripherals and machine memory can automatically load the next language access. program segment from cassette and con­ Commodore claims that the PET's BASIC tinue execution. I was able to do this by is at least 20 percent faster than other placing LOAD and GOTO statements , and the tests which (separated by a colon) on the same BASIC I have run support this claim. In addition, line; the old program segment seems to be Commodore BASIC is efficient in its use completely erased and replaced by the of memory, for it encodes BASIC state­ newly loaded segment, but data values are ments as they are entered so that keywords preserved. such as PRINT and INPUT occupy only one The PET's built-in operating system is byte. Another feature which can save time and memory space, especially when large arrays are involved, is the use of integer Data Types: Real numbers (eg: A), integers (A%) and strings (A$) of up to 73 characters. variables (which occupy two bytes) in place Arrays: Any number of arrays of reals, integers or strings with any number of of real variables (which require five bytes). dimensions. Programs are also stored on cassette in Precision: Ten significant digits for real numbers. encoded form. This speeds up the process Speed: Executes the loop 10 FOR 1;1 TO 10000,20 N EXT I in about 15 seconds. of saving and loading programs, but makes Statements: LET GOTO DIM it more difficult (especially in the absence READ IF ... THEN REM of documentation) to enter BASIC programs DATA FOR .. . TO ... STEP DEF FN RESTORE NEXT RUN from an external device such as an ASCII PRINT GOSUS CONT keyboard or a paper tape reader, or to write INPUT RETURN NEW programs, such as macroprocessors, wh ich GET ON .. . GOTO LIST ON . . . GOSUB CLR must manipulate program text as data. STOP For readers unfamiliar with Altair BASIC, END the PET's character string handling functions Operators: AND are worth mentioning. LEFT$, RIGHT$ and + <> OR >; NOT MID$ are used to extract a substring of <; specified length and position from a charac· / > ter string. LEN returns the length of a string, t < and VAL and STR$ convert numeric quan· Built·in ASS SIN FRE LEFT$ Functions: I NT COS TAB RIGHT$ tities to character string form and vice versa. RND TAN SPC MID$ ASC obtains the internal character code for SGN ATN POS CHR$ a given character, and CHR$ converts a LOG TI ASC EXP TI$ LEN character code into a single character string ST VAL for handling as such in BASIC. STR$ Other SAVE OPEN PEEK Machine Language Access Features: LOAD CLOSE POKE VERIFY PRINT# USR The PET user is not restricted to working INPUT# SYS GET# WAIT in BAS IC, for the PET is designed to support CMD entry and debugging of machine language programs, and even other languages and Table 7.- A brief summary of the features and performance of Commodore programming environments. The BASIC user BASIC The BASIC interpreter was developed for Commodore by Microsoft can examine or modify any memory loca· Inc, Albuquerque NM, designers of the original Altair BASIC According tion with the PEEK and POKE statements, to Commodore's engineers, the PET's BASIC actually includes some addi­ or call a machine language subroutine via tional features not documented in the preliminary users' manual, from which the USR function. Some nonstandard 10 this information was taken. devices can be handled with the aid of the

122 BYTE March 1978 WA IT statement, wh ich repetitively tests a nected by means of plugs to the keyboard, memory location (such as a PIA port) until CRT and built-in cassette. It includes four specified bits are set. Finally, the SYS com­ edge connectors wh ich reach the outside mand can be used to transfer "complete world through openings at the base of the control of the PET" to a machine language PET's cabinet. These edge connectors subsystem previously loaded into memory. provide: According to Commodore's engineers, 1. A second cassette drive interface it is possible to save and load machine lan­ with read, write, motor control and guage programs on cassette, and undoubt­ sense lines. edly an assembler in read only memory will 2. An 8 bit programmable 10 port, be offered some time in the future. A actually the unused portion of an machine language monitor, similar to MOS MOS Technology MCS6522 Versatile Technology's TIM, but utilizing the PET's I nterface Adapter (V I A). ke yboard and video display, has been 3. An instrument interface obeying the developed for th e PET. It was originally discipline of the IEEE 488-1975 intended to reside in the PET's read only standard. memory, but was squeezed out by other 4. The microprocessor's address, data software ·and is now loadable from cassette, and control buses. according to the latest word I've heard. Provision for expansion is built into the As of this writing, Commodore has not PET's read only memory operating system released the machine language monitor on as well. The second cassette drive and the cassette, nor any documentation describing IEEE 488 instrument interface appear to its capabilities. be fully supported by BASIC through the OPEN, CLOSE, PRINT# , INPUT#, GET# Expansion and CM D statements. Use of the V I A port One of the nicest aspects of the PET's and the address, data and control buses may design is the degree to wh ich expansion require some machine language program­ provisions have been bu ilt into the basic ming, although much could be done with unit. The main printed circuit board is con- the PEEK, POKE and WAIT statements

THE ALPHA·1 SYSTEM ~HARDWARE • Stores greater than 500K bytes per side of a C-60 ~RATED A BEST BUY tape. IN MASS STORAGE • Access a file in 17 seconds average on a C-60 tape. • Load 8K of data in less than 11 seconds (6250 baud). SYSTEMS • 100% interchangeability of cassettes with no adjust­ ments required or allowed. • Compatible with all popular S-100 Bus Microcom­ puters. • Audio track under computer control. • Eliminates the need for ROM/PROM monitors.

~SOFTWARE • MCOS, a powerful stand-alone cassette operating system, is operationally much simpler than a D.O.S., handles variable length named files, will update a file in place, packs or copies tapes with a Single command. • EXTENDED BASIC with MCOS permits array hand­ ling and concatenation of files, plus all capabilities of MCOS.

~ PRICES START AT $240 ~ APPLICATIONS • BUSINESS applications include mailing lists, payroll, ~ FREE BUYERS GUIDE billing, and inventory. If you are shopping for a tape or disk system for your • CASSETTE BACKUP for disk-based Systems not S-100 Bus Computer System, you do not have all the only provides large amounts of storage at low cost, facts until you have the MECA "BUYERS GUIDE TO but also provides for convenient storage of histori­ MASS STORAGE." This 10 page guide book provides a cal records. framework for evaluating cassette, cartridge, and disk­ • DEVELOPMENT SYSTEM features include a power­ based systems. Write for your copy today. ful operating System with an Editor, Assembler, and For complete information including the Dealer nearest Debugger, plus a variety of System utilities which you , write or phone: speed development. • OEM applications include P.O.S. data capture, word Ille~;1 processing systems, audio-visual presentation sys­ 7026 O.W.S. Road , Yucca Valley, CA 92284 tems, telephone call transfer systems. (714) 365-7686

Circle 65 on inquiry card. BYTE March 1978 123 And if the PET follows the patter n of other personal computers, additional systems and application software are likely to be offered by independents as well. Many ap pli cation programs in BASIC can be found in books and in the files of large scale computer systems. Some of these programs are copy­ righted and most will require some modifica­ tion to fit the features of Commodore BASIC, but far less effort should be required to adapt such existing programs than to write the programs from scratch. The PET has considerable potential in schools and universities, and it appears that many of the currently active software devel­ opers are especially interested in educational applications. I would not be surprised to see the PET show up in classrooms and uni­ versity computer centers across the country, taking th e load off game program burdened timesharing systems, and spurring new courses and educational research projects.

Availability and Delivery Initially Commodore followed a policy of "cash now, delivery later" which meant, in my case, delivery on Octobel' 11 1977 of a PET which I paid for in late June. This was Photo 5: The PET props open for easy service access. Besides the main nominall y within Commodore's contractual printed circuit board, the unit contains a TV chassis type circuit board and a ob li gation to deliver in 90 days. This situ­ third board in the cassette recorder. ation should change, however, as Commo­ dore builds up its manufacturing volume and works off the backlog of ini tial orders. in BASIC. Special programming could also As this is written, I have heal-d that a few take advantage of the VIA's peculiar serial dealers have demonstration units on display 10 capability. And theoretically , one could in their stores, and at least one dealer has unplug the built-in keyboard from the begun accepting orders on credit ca rd s. main printed circuit board and plug in Someday you may be ab le to buy a PET another keyboard and logic interface. at your local computer store and calTY it Again, Commodore to date has not pro­ home, but until then you should probabl y vided documentation of any of the expan­ base your pl ans and expectations on "worst sion options, and I have not been able to case" estimates of delivery time. test these features. But I did see the PET driving a programmable oscilloscope in a Warranty and Service demonstration at a trade show last summer. Service has always been a problem in For those interested, the IEEE 488 interface the personal computer industry . It repre­ standard documentation can be obtain ed sents an even bigger problem for Commo­ from the IEEE Service Center, 445 Hoes dore, since the PET will be distributed Ln, Piscataway NJ 08854, (201) 981-0060. through calculator dealers as well as com­ puter stores, to ordinary consumers as well Application Software as to computer hobbyists. Commodore's No application programs were supplied approach to the problem has been to design with the PET I rece ived, not even a demon­ the unit to be serviced as easily as possible. stration cassette which I had requested. Th e PET cabinet props open for easy But many of the first PETs off the pl"Oduc­ access, as shown in photo 5. The entire tion line are being delivered to people who unit contains only three individually re­ have purchased one with the idea of develop­ pl aceab le printed circuit boards. The main ing generally useful application programs. board can be snapped out and returned Commodore plans to reproduce and sell to the fa ctory or repl aced by a Commodore appl ication programs through its dealers, dealer. A 1 K byte diagnostic routine is in­ offering royalties to the software developers. cluded in the PET's read only memory,

124 BYTE March 1978 Photo 6: Th e PET received by the author was de­ livered with several faulty memory chips, which led to a variety of strange effects in BASIC as illustrated by this photo. Th e statement numbered 20464 was not typed by the user, and the state­ ment numbered 4720 was listed twice by the LIST command. A fter the bad memory chips were re­ placed, these symptoms disappeared.

so that with special test equipment this board is "self-di agnosi ng. " Th e seco nd board, fo r the CRT displ ay, is vir tuall y id entica l to th e same section of a chass is in a co nve ntional TV set. The th ird board, for the cassette dri ve, is simil ar to the circ uit boal'd fo un d in an ordin ary audi o cassette record er. Co mm odore be li eves that th e PET coul d be serviced by a TV repairm an equ ipped with a br ief se rvice manu al. It is not ye t clear, however, just ho w or whether TV from computer depot repairmen mi ght be licensed to re pair PETs Now you can get the ki ts . and th e manuals . .. to train yourse lf in under warra nty. Pres um ab ly ex perienced Micro processor Hardware develo pment com pu ter hobbyists co ul d read the service Computer Depo t" s exclusive " Kittature" I package includes The MMD-1 manual and di ag nose problems with their Microcomputer system - wh ich permits you to design your own ow n PETs, requestin g re pl acement parts interface in 10-20 minutes - and E & L from the fa ctory, but how Co mm odme BUG BOOKS V & VI with over 60 experiments. I mi ght react to thi s poss ibility is an open question. Of course, there is always the pro­ blem of latent bugs in the read onl y memory software, which a TV repairman might have some trouble di ag nos in g. Seri ously, the onl y rea li sti c approac h to handling software problems is for hobbyists an d PET dea lers to document carefully with exampl es any anomalous behav ior of their PETs, referrin g th e information back to the software deve­ lopers. At prese nt, however, PETs are bein g computer se rviced onl y at Comm odore's headquarters in Palo Alto CA. The use r mu st arrange to dePDtJ@ inC. Oth er ed uca ti onal ," Kitta­ ture" is also available. Sen d ship the unit to Palo Alto and mu st be "MaJdngE//icicocyEconom;car' fo r your FREE catalog from ~~:;':i:!:)~.:.';::' Minneapolis, MN 55435 Computer Depot todayl prepared to wait up to eight weeks for the L PET to be fixed.

126 BYTE March 1978 Circle 25 o n--- inquiry ca rd. Photo 7: The Commodore PET 2007 is an eminently usable machine, as is illus­ trated by this display of a 6502 assembler written in the machine's version of the BASIC language. This assembler was originally written in FORTRAN for use on large systems, and implementing it in BASIC was a relatively mechanical job of translating state­ ments and typing them into the PET.

Although eventually Commodore may face and the IEEE 488 bus, make it quite have a nationwide service network for the su itab le fO l' ex pansion and enhancement. As PET, my informal service experience with a small illu stration , despite the pl'oblems I the early uni t which I rece iv ed has been have had with my PET, I have been ab le to quite similar to that reported by owners of debug and put into use seve ral thousand other personal computers. I was unlucky lin es worth of BASIC programs. Among enough to receiv e a un it with three bad these is a 6502 assemb lel' written in BASIC, memory chips which caused a variety of a pmgram of about 700 lin es whi ch I strange effects such as those illustrated in orginall y wmte in FORTRAN for use on an photo 6. For several weeks after I received IBM 360 and a DECsystem 10. the PET I was unable to get anyone at For the casual user, the PET is a very Commodore on the phone and was left to low cost computer which can be program­ fend for myself. I suspected a memory med eas ily in BASIC, fOl' us e in schools, fOl' problem, but my memory test programs playing games and fOl' fairly complex ca lcu­ written in BAS IC apparently were not lations in engineering, statistics and the like. ex haustive enough to locate the faults. A better keyboard, a disk and a reliable Finally John Feagans, one of the designers printer would make it su itab le for some of the PET, called me, quickly di ag nosed the business app lication s. In fact, Commodore is problem and mail ed me a machine langu age sa id to be co nsid erin g development of a PET memory diagnostic program and some re­ " computer which would incorporate seve ral pl ace ment memory ch ips. With these aids I of these features. Whether the PET evo lves was able to find and replace the defective into a general-purpose com puter with chips in a couple of hours. a val'iety of pl'ogramming systems and periphel'a ls will depend on Commodore's Conclusion future mov es and on the activ ity of PET owners. The PET may well be an "appliance" The PET is far fmm the on ly alte rn ativ e computer, suitable for the most casual in the marketplace today, but it is a strong computer user or, with appropriate appli­ contender. If yo u are contemplating a cation software, for the average consumer. purchase, you would do well to compare its But it is also a powerful tool in the hands of featu res aga inst other offerin gs, tal k to an experienced computer hobb yist. The owners of the PET and other computers, and options and flexibility built into the PET, think about what you reall y want from a ranging from string handling and machine personal computer. I hope that this review lan guage access to the second cassette inter- articl e will help you in your evaluation.-

BYTE March 1978 127