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Homebrew Computer Club ' R obert Reiling, E d i t o r □ Po st Of fi ce Box 6 2 6 , M o u n t a i n Vi ew, C A 9 4 0 4 2 □ Joel M ille r, S t a f f Wr it er ' T y p e s e t t i n g , g r a p h i c s a n d e d ito r ia l service s d o n a t e d b y Laurel P u b lic a tio n s, 1 7 2 3 5 L a ure l R d . , Lo s G a t o s , C A 9 5 0 3 0 (4 0 8 ) 3 5 3 - 3 6 0 9 organizers Dr. W. J. Schenker, and R. J. Hendrickson are to be congratulated. MORE ON THE S -100-A prii, 1977. The First West Coast C om puter Faire being held April 15-17, 1977 at the San Francisco Civic A uditorium , N orthern California’s largest convention facility, will have a con ference session on the S-100 bus according to Jim War ren, Faire Chairperson. You can participate in this ses sion or others scheduled for the Faire. Write or call Jim Warren, Box 1579, Palo A lto, CA 94302, (415) 8517664 or 323-3111. LETTER—November, 1976. Samuel H. Daniel, V andenberg AFB, CA sent a letter asking to be put on the mailing list and enclosed a donation. He com m ented as follows on his activities, “ I presently have an 18K Digital Group 8080 System , to which I may add a pair o f Phi-Decks and a controller. It works as advertised and w ent from bits and pieces to assembled and tested in only 14,5 hours. Needless to say, I ’m pleased w ith and recom m end it.” Thank you for the p roduct inform ation and for the contribution to the Newsletter. CONTRIBUTIONS—The Hom ebrew Com puter Club New sletter is supported by contributions, both of articles and m oney. Your articles help keep inform a tio n flowing and all of us benefit. In this issue you will read about w hat others are doing with their com puters. W hat are you doing? Do you have a favorite software idea? How about a p roduct evaluation? Send me your article for the Newsletter. M oney, of course, is another requirem ent of the New sletter. Printing and postage are very expensive and so it follows the N ew sletter costs a reasonable am ount to produce and distribute. Please keep your contributions coming in. Mail to Hom ebrew Com puter Club New sletter, P.O. Box 626, M ountain View, CA 94042 or m eet me at the next Club m eeting. □ RANDOM DATA By R obert Reiling MEETING—Nov. 12, 1976. Acapacity crowd was on hand, estim ated at over 450 people for this m eet ing. A nderson Jacobson, Inc, had their term inals and, as promised, provided an inform ative talk about the Selectric m achine as used in their term inals. Particular ly interesting was the discussion of the way th a t the type ball is positioned to prin t a character. Also, the differences in the I/O unit as com pared to the office u nit were listed. The I/O Selectric is a heavy duty m achine developed for com puter use and workloads. The office Selectric does n o t have the heavy duty features. M&R Enterprises dem onstrated the Astral 2000 w ith the special version o f BASIC which has been spe cifically designed to operate in the Astral system . The Astral is available in fully assembled, turn-key condi tion as a partially assembled kit.T fhe kit saves a lot of m oney and is easy to p u t together since the m ajority of the electronics 'áré preassembled, burned in and tested. Marty Spergel and other .-xepresentitives from M&R discussed these and other features of this com pu ter system . If you missed the pieeting you-m ay obtain Astral 2000 inform ation by writing M&R Enterprises, P.O. Box 61011, Sunnyvale, CA 94088. S-100 SYSTEM SYMPOSIUM—Nov. 20, 1976. Well over 100 people attended the S-100 System Sym posium held at Diablo Valley College. Three perspec tives were given by Dr. Harry Garland, George Morrow and Lee Felsenstein. It was noted by Lee Felsenstein th a t a large variety of products are available th a t utilize this bus. Harry Garland pointed out th a t the bus sys tem is basically a good product. George Morrow dis cussed the com plex nature of the bus. A panel discus sion, m oderated by Jim Warren, brought o u t a num ber o f opinions b u t the panel generally agreed the S-100 bus system will be used for several years because so m any products use it. In order to get better definition of bus signals and electrical requirem ents, it was sug gested th a t publishers print m ore bus inform ation and act as a clearing house for com m ents. This was the first symposium held covering the S-100 system. It was very well done and certainly inform ative to all in attendance. Indeed, it seems everyone m ust have learned som ething new. The ONE M A N ’S SYSTE M B y C harlie P ack My background is in program ming, including 10 years of experience m ostly on large-scale IBM systems. I ’ve used IBM 1401 A utocoder, IBM 360 Assembler, PL/1 and COBOL for m any varied applications, includ ing some of my own personal accounting and inven tory chores. In 1973 I w ent to w ork for an electronics 1 HCC N ew sletter/V ol. 2, Issue 11-12/D ecem ber 10, 1976 firm which m anufactures intelligent term inals using the then-new Intel 8008. A lthough I d id n ’t program the 8008, it soon became apparent to me th a t m icropro cessors were good for a lot m ore than just form atting data on a video screen or controlling traffic lights. In the m eantim e, I had gotten interested in digital electronic circuitry while building digital clocks and m eters, and finally I built and got running a RadioElectronics “ TV T ypew riter” (the TVT-1, w ith the boards th a t are stacked like cordw ood). Then the bug h it me for sure—I wanted my own com puter. So in November 1975 I devised a point system and rated all of the available hobbyist com puters. I had been renting tim e on an IBM 360/30 ffor $30 per hour, so I w anted the capability to run a high-level language and later a disk operating system. The clear w inner was determ ined using my point system and right after New Y ear’s my A ltair 8080 kit arrived (when I ordered my A ltair I d id n ’t know ab o u t the IMSAI com puter). A t the present tim e I have up and running in my Altair a Processor Technology m otherboard, 3P+S I/O interface, tw o 4KRA static mem ories and tw o 4K dynam ic memories. I use an ASR-33 Teletype m achine for I/O . MITS BASIC version 3.2 is used for all ac counting applications at present. The aforem entioned hardw are is now being used to do investm ent portfolio and incom e tax analysis and to produce a cross-reference index to magazine articles. The hardw are now being used represents a practical m inim um for the perform ance p f the applications now being run. Assuming th a t the necessary planning and analysis has been done, com puter inplem entation of m ost sim ple business-type applications n o t involving large am ounts o f data involves four basic needs: a) Some means of transferring original data from docum ents to the com puter. For an on-line system this is done using a suitable keyboard and some type o f edit/update program. b) Some means of storing the data outside of com p u ter m em ory. c) Processing o f data, usually involving data selec tion or sorting logic and calculations. d) R eporting of the desired inform ation to the user. This is the end p roduct o f th e sytem . The BASIC line editor itself satisfies the first tw o needs in my applications. Here is a com plete on-line data entry program which can add new data, change existing data and delete data. O f course, the entire data file is in m em ory, b u t allowing 6K for BASIC and 4K for a good-sized program (leave o u t com m ents and use m ultiple statem ents per line to save m em ory space), leaves 6K bytes rem aining for data. T h a t’s enough for 100-150 transactions with 3-6 data items per transaction, using DATA statm ents. A year’s investm ent portfolio transactions are no p rob lem! I use line num bers of 10000 and up for DATA and less than 10000 for program code. The com m and LIST 10000 stores the updated data file on paper tape. The latter two needs are satisfied by programs I write in BASIC and use with the printer on my ASR33. By following set conventions for line num bers and by using com m on subroutine for READing data, a HCC Newsletter/Vol. 2, Issue 11- 12/December 10, 1976 program m er may use a DATA file w ith several pro grams. To prin t o u t or punch the program code only, I type LIST and when the last statem ent starts to prin t I h it control-C a couple o f tim es to stop it. A lthough my im plem entation of investm ent p o rt folio is crude, it illustrates th a t m inim um hobbyisttype equipm ent can be practically utilized for many small business needs. A video display such as the Pro cessor Technology VDM-1 and a tape cassette storage system could be substitued for—or used in addition to —the ASR-33. The use of E xtended BASIC would greatly facilitate separate storage and m anipulation of data and programs and the display of form atted re ports. My future plans, as far as hardw are is concerned, include the acquisition of m ore m em ory, a ROM m onitor which can be used to load BASIC, a video display, cassette tape interface and hardw are backup capability. By the tim e this article is in print, I will have a Processor Technology 8KRA RAM board and a MITS PROM board up and running, with a system m onitor in six 1702A PROMs. The latter has loaders for MITS BASIC (any version) and for softw are in the Intel hex form at, a block move, full TTY support, and switchable hexidecim al or octal m ode capability, in addition to norm al m onitor functions. It will be made available to hobbyists via the HBCC library and through the Byte Shop in Santa Clara. My future plans for software include enhance m ent of the m onitor to support tape cassette I/O and some type of video m onitor display. M emory diagnos tics, games and o ther program s will be developed for use with the run on a cross-assember of my own design and w ritten in ANSI COBOL for execution on a medium- or large-scale system . A suitable alternative to this w ould be a Processor Technology ALS-8 develop m ent system and a DECwriter or similar printer, if the latter could be obtained a t a reasonable cost. I would be interested to hear from other hobbyists as to w hat they would like to see in the way of so ft ware for the 8080 or Z80. How about a full operating system for m ultiple cassette tape drives? What features would you like it to have? Is there an interest in games (such as Star Trek) in m achine language for smallcapacity systems? I can be reached at 25470 Elena Rd., Los Altos Hills, CA, 94022. Home phone (415) 941-0495, betw een 7 and 10 p.m . on week-day eve nings would be preferred. □ f ( W I SC O N SI N A R E A COMPUTER S O C IE T Y By Robert Reiling \ J The Wisconsin Area C om puter Society has been holding m onthly meetings for the last twelve m onths and has a paid m em bership o f over 80 persons. They are establishing a good software library, and can com m unicate via Cassette Tape (Tarbell, Digital G roup and K. C. Standard) and Paper Tape. Recently they pub lished their first new sletter. C ontact Don Stevens, Chairman, Wisconsin Area C om puter Society, P.O. Box 159, Sheboygan Falls, WI 53085. □ 2 10 LET A = B + 1 234 11 . 20 GOSUB 100+A GETTING THE M O S T OUT OF T I N Y BASIC T o m P ittm a n Here, when you type RUN, the program will stop with the error message, C o n tin u ed fro m last issue. Execution Speed TINY BASIC is actually quite slow in running pro grams. T hat is one of the hazards of a two-level inter preter approach to a language processor. But there are some ways to affect the execution speed. One of these is to use the keyw ord “ L ET” in your assignment state m ents. TINY BASIC will accept either of the following tw o form s of the assignment statem ent and do the same thing, •184 AT 11 Now we can PRINT A, B, etc., to see w hat m ight be wrong, or type in GOTO 20 to resum e, with no loss to the original program. As we have seen, there is n o t m uch th at TINY BASIC cannot do (except m aybe go fast). Sure, it is som ew hat of a nuisance to write all th a t extra code to get bigger num bers or strings or arrays, b u t you can always code up subroutines which can be used in sever al different program s like the floating point add above (line 1000-1250), then save them off on paper tape or cassette. Rem em ber, your com puter (w ith TINY BASIC in it) is lim ited only by your im agination. R=2 + 3 LET R=2+3 b u t the second form will execute m uch faster because it is unnecessary for the interpreter to first ascertain th a t it is n o t a REM, RUN or RETURN statem ent. In fact, the LET keyw ord is the first tested, so th a t it becomes the fastest-executing statem ent, whereas the other form m ust be tested against all twelve keyboards before it is assumed to be an assignm ent statem ent. A nother way to speed up program execution de pends on the fact th a t constant num bers are converted to binary each tim e they are used, while variables are fetched and used directly w ith no conversion. If you use the same constant over and over and you do not otherwise use all the variables, assigning th a t num ber to one of the spare variables will m ake the program both shorter and faster. You can even m ake the assign m ent in an unnum bered line; the variables keep their values until explicitly changed. Debugging Very few programs run perfectly the first tim e. When your program doesn’t seem to run right there are several steps you can take to find the problem . First of all, try to break it up into its com ponent parts. Use the GOTO com m and and the END state m ent to test each p art separately if you can. Add extra PRINT statem ents along the way to prin t o u t the vari ables you are using; som etim es the variables do n o t have the values in them th a t we expected. Also the PRINT statem ents will give you an idea as to the flow o f execution. F or example, in testing the sort of pro gram above (lines 500-700) I inserted the following extra PRINT statem ents: REFERENCES: (1) T I N Y BASIC User's Manual. Available from Itty B itty C om puters, P.O. Box 23189, San Jose, CA 95153. (2) D octor Dobb's Journal, No. 7, p. 26. Available from PCC, P.O. Box 310, Menlo Park, CA 94025. Finally it should be noted th a t GOTOs and GOSUBs always search the program from the beginning for their respective line num bers. P ut the speed-sensitive part of the program near the front, and the infrequent ly used routines (set-up, error messages, and the like) at the end. This way the GOTOs have few er line num bers to wade through so they will run faster. □ INE X P E N SIV E GRAPHICS W orkshop A n n o u n cem en t _____________ A w orkshop regarding inexpensive graphics is being planned on the East Coast. It will be held next year and is sponsored by Sigraph of the A.C.M. Interested people may co ntact William E tra, 42 E. 23rd Street, 7th Floor, New York, NY 10010. □ ABOUT RECONNECTING THE IM SAI POWER T R A N SF O R M E R 525 PR t"x"; r- . r_ _ t M 545 PR . ; 555 PR This gave me an idea where in the sort algorithm I was, so I could follow the exchanges (the “ x ”s), where each line represented one pass through the main loop. Endless loops becom e m ore obvious this way. If you have not used all the sequential line num bers, you can insert breakpoints in the program in the form of a line num ber with an illegal statem ent—I like to use a single period, because it is easy to type and does n o t take m uch space: B y D ave K in kade When I changed the line in p u t connections to my IMSAI transform er (a Trane 3751), I was chagrined to learn th a t it did n o t m atch the diagram on the PS-B schem atic (Rev. 2, 3/3/76). The term inals are actually: (1) com m on, (2) for 105 V, (3) for 115 V, (4) for 125 V. For exam ple, I connected to (1) and (4) instead o f . ( l ) and (3) to lower the o u tp u t voltage and generate less regulator heat. □ 3 H C C N e w sle tte r /V o l. 2, Issue 1 1 -1 2 /D e c e m b e r 10, 1976 v l r í : S 'r r N*l» i ^ H o m * * e april, 1977 • san francisco P .O . Box 1 5 7 9 , Palo A lto , CA (415) 8 5 1 -7 6 6 4 , 3 2 3 -3 1 1 1 IIIIIIIIIIIM IIIM IM IIIIIIIIIIIIIIIIIM IIIIIIM ^ ^ ^ HOW I BUILT~~ A Í Y F I R S T C O M P U T ER , O R F O O L S R U S H I N WHE RE E N G I N E E R S F E A R TO T R E A D Building the boards up to o k relatively little tim e. The largest block of tim e during construction was devoted to running wire. A total of nearly 1,000 feet of 26 ga. and 100 feet of 16 ga. was used. C heckout was prolonged considerably by the unfortunate inser tion of the CPU board backwards in the m otherboard. The snaps, crackles and pops would have done Rice Krispies up proud. Invaluable assistance by a long suf fering friend, G rant Connell, finally got GEORGE up and running. The system a t the present tim e consists of the 8080 m icrocom puter with 24K of 2102 RAM, 12K of 1702A EPROMs, a KSR-33 Teletype, a cassette record er, I/O boards for the teletype and cassette plus a high speed paper tape punch. Within the next six weeks, GEORGE will acquire a high speed paper tape reader and a VTT 4000B video term inal. I can tell the m em ory of the pain, sweat and frus tration incurred during the construction is beginning to fade. A few weeks ago, I saw the ad for the Micro Nova m inicom puter chip set and thought, “ Why, I bet th a t I can get one of those jewels up and running for alm ost nothing! ” By the way, I have a list of parts th a t you have p ro bably got just sitting around gathering d u s t— □ By Norman Walters A course, “ Introduction to C om puting,” taken during the fall of 1975 was my first exposure to the w onderful world of com puters. By m id-term , the itch to have my own was beginning to be felt. The itch faded considerably when the prices of the com puter kits on the m arket was considered. A fter m uch thought, I decided one could be built at hom e a t a price my wife w ould n o t be able to use as grounds for divorce. Naturally, the fact th a t the largest project previously tackled was a digital clock did n o t cool m y optim ism a whit. Ten m onths later my hom e brew com puter is built and the cost was m uch smaller than if a com m ercial kit had been purchased, b u t the tim e and effort expended have been trem endous. During the construction of GEORGE, every costcutting trick possible was em ployed. N aturally, the m other board was built from scrap cut-offs bought at the club, and 80-pin connectors were cut to form 100pin connectors. Every friend I had plus some who had n o t realized th a t we were even on speaking term s was presented w ith a list of parts needed and a strong hint given, “ If you have any of these parts just lying around, you m ight be able to force me to take them off your hands if the price is right!” I haunted all the surplus electronics stores and pored over the Poly Pak catalog like it was a dirty book. Because o f this approach (cheap), parts did n o t present a m ajor problem . The CPU board and control panel board required the lar gest outlay of tim e. A fter some initial delays, both were purchased through the club by group buy. «»* sue* ST A T U S aodress 'XOItci HCC N ew sletter/ Vol. 2, Issue 11-12/D ecem ber 10, 1976 4 / V T I N Y BASIC OR HOW M Y F A M I L Y CAME TO L O V E M Y COMPUTER By Ray Boaz ....... :.r.................... z ^ ^ m line is given. The com puter can keep score and if the problem was a “ h a rd ” one, a “ VERY GOOD” is prin ted. This is a short and simple program , b u t to a nine year old girl, it is like magic. I d id n ’t get off th a t easy, however. A t my side all the tim e (or was it on top of me) was my son, Chip, who is only six. Since he is n o t up to m ultiplication y e t I had to do som ething else. If Tiny BASIC could m ultiply th a t easy, it m ust be at least as easy to do the addition facts. So w ith a few chnges in the same program , another m em ber of the family was into the com puter. Well, th a t accounts for tw o o u t of three. What ab o u t my wife? Glad you ask. She does n o t glare at it when she walks by and has even started saying some al m ost nice things ab o u t it. If this keeps up, I may have to start on another com puter for myself. Oh, one other thing. Heidi is busy setting up times for her friends and m aking arrangem ents to take the new to y to school. There seems to be no end o f w hat can happen when your kids can com pute. □ \ I / One sure way to get the support of y our family for all the hours th at you spend w ith your com puter (only) is to let them get some “ hands o n ” tim e. The problem is how m any kids, let alone wives, understand binary, octal, hex or getting a program into the % $& t thing to do something. So how do you do it? Well I got Tiny BASIC for my AMI Proto system (by Tom P itt man) and it w orked out ju st great. The first thing I did was write a program for my nine year old girl, Heidi, to use for her m ultiplication facts. A fter one m inute she was really into it. The pro gram generates tw o random num bers less than twelve, prints them (i.e. 9 x l l = ) , waits for the p roduct to be typed in, and then com pares the entered p ro d u ct to th e calculated product. If the answer is correct a new tH 0Q&CG) F or sale: Cryptographic program th a t will baffle the codebreakers of the CIA. ENCODE an d /o r DECODE your private correspondence for m axim um security. D ocum entation of cypher technique, program listing and punched paper tape in BASIC for only $6. Jon Stedm an, 1528 Sum m it Rd., Berkeley, CA 94708. F or Sale: IMSAI 8080, 8K D utonics m em ory, Poly m orphic video term inal interface, Tarbell cassette in terface, A ltair 2SIO w ith one port, keyboard and J. C. Penny audio cassette recorder. Assembled. $1775. C ontact J. Gill, 497-4715 (days), 321-6289 (evenings). K leinschm idt 311 printer, 40 char/second, 80 charac ters wide, parallel ASCII input, level conversion from -1 2 V can be tapped from printer pow er supply, full docum entation, has m odem card, autom atic shut-off after 60 seconds of no data, good operating condition, needs cleaning, $300; another 311, has pow er supply, no other electronics, excellent m echanical condition, $150; extensive supply of spare parts, $50; all of the above together, asking $400; Wm J. Schenker, M.D., 2086 Essenay, W alnut Creek, CA 94596, (415) 9396296. SOL User G roup now form ing. If you own or have ordered Processor T echnology’s SOL com puter, please send your nam e, address, phone num ber and ideas to Bill Burns, 4190 Maybell Way, Palo A lto, CA 94306. W anted—Carpool or riders to Fairchild (or Ellis St. area in M ountain View from the Sum m it Rd. area in the Santa Cruz m ountains. Must be willing to get going early as I like to avoid traffic. Joel (415) 962-3372 (days) or (408) 353-2663 (eves). C om puter store opens in Sunnyvale—recreational Com p u ter Centers, 1324 South Mary Ave., Sunnyvale, CA 940S7. Phone 735-7480. HOW TO GET THE NEWSLETTER A nyone interested in com puters as a hobby may receive the Newsletter by sending a request to the Homebrew Computer Club Newsletter, P.O. Box 626, M ountain View, CA 94042. The Newsletter is distribu ted m onthly at the club m eetings and is also mailed to individuals w ho are unable to atten d the meetings. If you have an input to the Newsletter, send it in and it will be published as quickly as possible. However, the editors cannot promise th at everything sent will be published im m ediately. All m anuscripts m ust be typed and carefully proofed. All listings and diagrams should be as clear and easy to read as possible. The Newsletter is m ade possible by yq ur donations. Please rem em ber th at we m ust pay for postage, labels and printing. D onations m ay be given to Ray Boaz at the club meetings or sent to the above address.□ CLUB LIBRARY Gordon French, club librarian, has lots of interes ting m aterial and is able to loan it to anyone w ith a definite need, b u t . . . please adhere to the following: ☆Limit your telephone calls to the hours of 7PM to 9PM weekdays only. This is im portant. G ordon’s phone num ber is (415) 325-4209 in Menlo Park. ☆Be specific w ith your requests and G ordon can probably help you—he cannot random ly review the contents o f the library for you. ☆No reproductions will be m ade of any materials. ☆All m aterials loaned m ust be returned so they are available for others to use in the fu tu re .□ 5 HCC Newsletter/Vol. 2, Issue 11-12/December 10, 1976 STAND-ALONE ADAPTER FOR VDM-1 By Lee Felsentein VGO VCC HR W LS2 (p*r'.~eE4)ÇojEstop)— This circuit allows the operation of the Processor Technology VDM-1 as a stand-alone term inal. It in cludes a UART for serial data com m unication with EIA RS-232 signal levels. All data to the VDM comes through the UART, so a “ local loopback” connection is necessary from the D ata O ut term inal to the D ata In for half duplex operation. Two switchable Baud rates are available if a SPDT switch is connected to switch Baud R tn to Baud 1 or Baud 2. The Ready o u tp u t from the UART allows operation from a generalized parallel interface at m axim um speed. The Break input moves the o u tp u t to a space condition and is used as an escape character in various systems. The circuit requires a connection to an external -1 6 V to -1 9 V supply; +5 V pow er is supplied by pin 16 of IC23 from the regulator of the VDM. The cir cuit draws very little current since m ost logic is CMOS. The -1 2 V and +5 V connections shown are for key board power. On power-up, the circuit initializes to a clear screen w ith a cursor in the lower left corner. N on-control characters are displayed and rolled up when a 64 char acter line is filled. CR will term inate a line and roll it up. A LF im m ediately following the CR will be ig nored, as will a LF following any num ber of DEL (rubout) characters which in turn follow a CR. A second LF, or one w ithout a CR preceding, will be treated like a CR-LF com bination. F F will initialize the screen. BS will be recognized and the cursor will move back and will erase the last character. A t the left end of the line the cursor will jum p to the right end and will cause a roll dow n of the line above. This will n o t occur if there is n o t te x t on the line above. The cursor will jum p to the 64th location w hether or n o t it is visible there. If the previous line was term inated by a CR, the cursor disappears until backed over the CR. The circuit m ay be constructed using wire-wrap or solder; layout is n o t critical except th a t proper supply bypassing techniques m ust be used for the TTL ICs. Capacitors (O.lptF) should be connected betw een the +5 V and GDN pins of these ICs to prevent supply cur ren t pulses. The tw o boards m ay be interconnected with ribbon cables and DIP headers which plug into the IC sockets indicated on the drawing. EPt RR1 uA pr (k eoT Y - T ft 1 T R -,fe 0 2 B A r - s - f O '3 T P 2. (n ao 3 29 3« ( KBD A- y ( KBD 5 y ( K B Q 10 TR 3 y - ftR q TR4 TR 5 JZ - RR5 TRb bY- 11 33 ( kbp a)~ H Rfr TR7 TRB RR 7 " V )£ > THPE VDD {¡ READY TRC RRC > TP.O RI Ckbd sTfe ) V *rft£2poca^ity 5 K Cbaud i ) (£AuOBTW (R-V*. O — x (brpXJQ—A/vV i : IjTtf — W\r ioK fpftT ;~n)—A/\/V---- -* (3 2 0 . ilk THE F O LLO W ING M O D IF IC A T IO N S TO THE VDM A R E N EC E SSA R Y «4759 1. C u t trace on solder side fro m pin 4 o f IC 17. 2. C u t trace from pin 13 o f IC 10 o n c o m p o n e n t side. 3. C o n n e c t a ju m p e r from pin 6 of IC 17 t o pin 13 of IC 10. 4. C o n n e c t a ju m p e r fro m pin 7 o f IC 31 t o pin 4 of IC 17. 5. C o n n e c t a ju m p e r from pin 3 o f IC 31 to pin 7 of IC 13. 6. C o n n e c t a ju m p e r from pin 8 o f IC 15 to pin 9 of IC 31. 7. C o n n e c t a ju m p e r fro m pin 3 o f IC 41 to pin 15 of IC 31. 8. R em ove ICs 18, 23, 24, 28, 29, 31, 3 2, 33 , 34, 3 5, 37, 38 , 39 and 40. 9. If n o t y e t installed, resistors R27 th r o u g h R32 and R41 th r o u g h R 48 m ay be o m i tt e d fro m assembly. □ HCC N ew sletter/V ol. 2, Issue 11-12 /D ecem ber 10, 1976 PI ZUZ2.Z2 y > j \ i<pk. ( H —'VW~,° T»y y »>■ 1*. TM---6 i_ r i f -p V*®II > CXZX) N O T E S i UNLESS I. a l l r e s i s t o r s t CAPACITOLA AU A U CDODÉS 6 in IN O T H E R W I S E SPEC o h m s , s v . ,i/<w HlCftOCARAOS 1N4W8 o* 1N9H ¿3K 7 5 0 KH Z ■vvv «VRtTF ic z® «050 5C H U X X E N 6 4*3* LOAD LINC ^ > K ) COUNT -m 4CS0 8 - tlK w v- 4LS O « N t E«fc — < 3 < Q ( 43 4Y 23 ZY IC Z 3 0 UV4T -t— A A /V I— A A /V % 3K 1C 24 ♦030 74LS t5 7 5 rRfc W-ANK D lS R 440* A /v V 3 3* IC Î1 ♦© O I T 400' ^' l 4 0 Z7 404^ P ^C R S C H E M A T I C - VDM-1 STAND-ALONE ADAPTER r « A i» iT7fc t fE lS E N S T tIU 7 <W HCC N ew sletter/V ol. 2, Issue 11- 12/December 10, 1976 SOfiûON F R E N C H ’S CH<»f*-CHOO T R A I N OR IOLF f a n t a s i e s o n a v d i s c r e e n 0000 0000 0000 0000 0000 0000 0000 0000 00 00 0001 0003 0006 0009 000B 000C 000D 0002 000F 001? . 001? 0018 0 0 l'A 0 0 1D 00?0 0022 0025 0028 002A 00 2 D 003 0 0032 0035 0038 00 3 A 0 0 3D 0040 0042 0045 0048 004A 00 4 D 0050 0050 0051 0053 0054 0055 0058 AF D3 21 01 36 23 0B AF A8 C2 21 11 06 CD 11 05 CD 11 06 CD 11 06 CD 11 06 CD 11 06 CD 11 06 CD C3 C8 8 4 01 00 08 20 09 F7 00 0E 50 2B 0C 50 30 09 50 34 04 50 3R 02 50 3C 01 50 3E 01 50 59 19 36 6F 23 05 C2 51 C9 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0000 0010 0020 0030 004C 0050 0060 0070 00S0 0090 0103 0110 0123 01 3 0 01 40 0150 0160 0170 0180 0190 0200 «3210 0220 0230 0240 0250 0260 0270 0280 0290 0300 0310 0320 0330 0340 0350 0360 0370 0380 0393 0400 0410 0420 0430 0440 0450 0460 0470 HCC N ew sletter/V ol. 2, Issue 11-12/D ecem ber 10, 1976 HiHiiHiMiiiiiiiiiiiiijiiiijM THAI iM EMPTY XRA OUT LXÎ LXI «vi I NX DCX XRA XRA jnz LXI LXI ¡IVI CALL LXI MVI CALL LXI MVI CALL LXI MVI CALL LXI MVI CALL LXI MVI CALL LXI MVI CALL JMP S-ÎO 1 S MO 2 DAD MVI INX DCR J NZ RET 8 A ONCE UPON A TI ME» 0CSH IN A CURI OUS L I T T L E H » SHED PLACE THERE WAS . . A TI NY TRAIN B »2 0 4 5 M» 20H « , AND I T STAYED IN A H . TI NY SHED B • . t h a t was a l l e m p t y A B EMPTY Hi CLOUD . . E X C E P T FOR A HUGE D»0 B* 14 B S MOI I D »4 3 L L Bf 12 SMOl 0 W D *43 B *9 Y SMOl C D»52 B »4 L SMOl 0 U D »59 B *2 D SMOl D ♦ 60 0 F B» 1 SMOl S D*62 S» 1 M SMOl 0 ENGIN K E D • .COUGH M#SMOKE H 8 . . COUGH S MO 2 * COMING O'JT OF TH£ STACK OF 04 04 04 01 04 01 04 01 04 01 04 01 04 01 04 04 01 04 01 04 01 04 01 05 01 05 05 05 01 05 01 35 01 05 FF 05 00 CC 01 33 00 00 0430 • 0 4 9 0 ENGINE 0500 0510 0520 0530 0540 0550 3560 3570 0530 0590 0600 0610 0620 0 6 30 0640 0650 0660 0670 0680 0690 0730 07 10 07?0 0730 0740 0750 0760 0770 0730 0790 0800 0 3 10 0820 0330 0340 0850 0860 087C 0830 RAILS 0890 0900 0910 0920 0930 0 9 4 0 HOSTL 0950 0960 0970 FIRE 0930 0990 10 0 0 10 10 10 2 0 10 3 0 1040 1050 1060 1070 LXI MVÎ LXI MV I LXI MVI LHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD SHLD SHLD LHLD SHLD LHLD SHLD LHLD SHLD LXI LXI MVI !NX I NX XR A XRA JN ï LXI XCHG LXI MO V IN X H*SHED*322H A T I N Y L O C OMO T I V E M » 1 6M WI TH A L I T T L E SMOKESTAK H»SHED*325H AND A L I T T L E BELL M»07H H »SHED*327H . . A N D A T I N Y DOME M*6EH « • AND A CAB CABl S H E D * 3 2 A H WI T H WI NDOWS * . SO THAT YOU COULD CAB2 S H E D * 32CH SEE I N T O WHERE THE CAB 3 . • E N G I N E E R AND THE S H E D * 3 2 EH F I R E M A N S A T * SOI 1 » * I T HAD A B E A U T I F U L SHED* 361 H POLI SHED BO I 2 • . BRASS S HED* 36 3H BOILER BO I 3 * • WI T H S H E O * 3 6 5 H THE NUMBER S H E D * 3 6 7 H " 9 9 " ON THE BOI4 « • S I D E OF S H E D * 3 6 9 H THE CAB BO I 5 . * BUT YOU C O U L D N ' T S H E D * 3 6 8 H SEE E I T H E R THE # . E N G I N E E R OR THE BO I 6 S H E D * 36DH F I R E M A N FRA 1 « • THE L I T T L E E N G I N E S H E D * 3A 0H ALSO * . HAD A COWCATCHER F RA2 S H E D * 3 A 2 H AND LOTS OF FUNNY S H E D * 3 A 4 H WHEELS AND THE S H E D * 3A6H T H I N G S THAT CONNECTED • « AND TWO VERY T I N Y FRA 3 S H E D * 3 A 8 H WHEELS AT THE VERY FRA4 ♦ • VERY BACK S H E D * 3 a AH ALTOGETHER I T LOOKED FRA5 * * Q U I T E LONEL Y AND YET S H E D * 3ACH I T a p p e a r e d v e r y B » **2 1 H » FUNNY J US T S I T T I N G H » S H £ D * 3DEH THERE ON THE M# 19H » . RAILS B # * WI T H N OT H I N G AT ALL H • • EVER A « • TO DO B . . W E L L ! RAILS * . L E T ’ S RUN I T J U S T FOR FUN HtRRY GET T R A I N Ol)T OF SHED • MOVE I T FROM SHED H * SHED A »M LIGHT FIRE H xchg MOV I NX MOV XCHG GPI JNE CALL JMP 9 M »A H A *H . • MOVE 0D0H FIRE END OF YARD? NO* MAKE MORE STEAM! GO TAKE T R I P NO ROUND T R I P S * J U S T A GAI N travl HOSTLE IT DO H CC N ew sletter/V ol. 2, Issue 1 1- 12/December 10, 1976 0020 00ED 00F0 00F1 00F4 00F7 00F8 00 F9 00F A 00pB 00FE 00 FF 002 F 0 10O 0 104 0 J 05 0106 0107 01 0 8 01 0 9 010 4 0 1 OB 0 10E 01 0F 01 0F 01 4? C5 CD F F CD 0 F Cl 08 AF A8 C2 F 0 C9 21 0E 7E 2B 77 23 01 D0 03 00 01 00 CC 23 7C B9 C2 0 4 C9 21 0 1 1 2 7E 0 11 3 23 0 1 1 4 FF 0116 02 01 19 2 3 01 1 A 7E 01 IB FE 01 ID C2 0 I 20 11 0123 0 123 06 01 0 5 7 ? 0 12 6 05 0 1 2 7 CA 012.4 2 3 012P 73 0 1 2C 2 3 0 120 05 0 1°E C ? 0131 0 1 3 1 FE 01 3 3 C ? 0106 1 1 0 1 39 C* 0 1 0C 2 F 0 13F 0 2 0141 11 0 1 A4 0 3 0 147 FE 01 4 9 C2 01 40 1 1 0 14F C 3 01 5 2 0 1 5 ? 01 0 1 (70 CC 06 12 01 11 31 0 1 7E 1 4 1030 1090 • TRAVL 1100 1110 1120 1100 1140 1130 1160 1170 1180 1190 1200 1210 1220 1230 1240 1230 1260 1270 1230 CHOO 5? 25 14 3C 20 23 13 47 *F 23 1? 1A 20 23 pa 01 01 01 13 01 01 lp 01 01 11 01 08 COAL 1200 1300 1310 1320 1330 1340 1350 1360 1370 1332 1390 1400 1410 1420 07 * STROK LXI MAKE TRIP 13 C H U F F ONCE MAKE F ORWARD TURN WH E E L S MILES POSH CALL CALL POP OCX XRA XRA JN3 RET B STROK TURN B B A B CHOO LXI MVI MOV OCX MOV I NK I NX MOV CMP H * 0 C C >3 1 H MOVE DOWN THE T R A C K C *0D0H A ♦M ADD MORE COAL H M# A H H A »H C E NOUGH C O A L ? COAL NO» P U T MORE ON ! J ( nJ2 CLICK MO T I O N OD OME T E R 13 MI L E S NO DO N E X T YET? TRIP RE T • TURN HISS F O UN D AXL E LXI MOV I NK CPI JN3 I NX MOV CPI JN3 LXI H * 0 C C MF H T URN WH E E L S A *M H 6 F I N D C OWC G T C H E R HISS LOOK A G A I N H A «M 11H WHAT Q U A R T E R T U R N ? NKT1 D » 1 4 7 EH N E X T Q U A R T E R TURN MVI MOV OCR J? I NK MOV B 17 M#T) 3 WORK H M* E H 3 AXL2 * 1430 1440 1450 1460 1470 1430 A XL 1 A XL2 14 20 INK 1500 1510 15 2 0 1530 1540 1550 1560 1570 1580 1590 1600 16 10 1620 1630 16 4 0 1650 1660 OCR JN 7 HCC Newsletter/Vol. 2, Issue 11- 12/December 10, 1976 B » 6 4 * 13 DO 4 A X L E S WH E E L S MOVED H E R E L A S T WHEEL? I ' V E BEEN W O R K I N * . . . . . O N T HE R A I L R O A D . . ( S I D E R O DS MOVED H E R E ) . . A L L THE L I V E . . . . L O N G D A Y ................ * N XT 1 NXT2 MXT 3 CPI JN 3 LXI JMP CP I JN7 LXI J MP CPI JN3 LXI J M° 14H QUARTER NXT2 D * 132DH A XL 1 13H QUARTER LXI B ♦3000 10 TURN NXT3 Di 1 25 FH AXL1 12H QUARTER AXLE D * 1 1 2 QH A XL 1 * WORK TURN TURN 5 55 03 rt <86 np r* 5H F 6 P! 5A 0 5D ]? 0 Í* 5 F 0 4? 0 63 0 63 0 40 C 2 63 0 1 AF ûP 62 55 31 C9 6 3 C 3 60 £ 0 0 66 0 66 0 0 0 0 0 0 0 0 0 0 0 0 P 66 66 66 0 1 10 63 1 0 51) 6 A 7F 2 0 6 C 23 0 A 6 F 0 A 19 70 72 74 76 73 7A 76 7F 30 32 04 35 0 0 0 0 0 0 0 05 0 05 PA 0 A 0 A 5B 30 39 50 90 06 11 11 6F 6F 20 2D 9(7 9D p0 19 19 Ç*Í* 1 670 OIL 1630 16<30 1700 1710 1 700 1730 17 40 î760 * 1760 • d u t 1770, GUI T DCX IN ANI JNF XRA XRA JN 3 Ra.T B♦ 0 EDA QUIT A B OIL F.GU 40H 1 800 RRY 18 10 SiOKE 18 2 0 C A3 1 EQU FQU Dû! 6 FH 1830 1840 1850 I8 60 1870 1 880 1890 19 0 0 19 10 1920 19 30 du 10 4 0 19 5 0 1963 1970 1980 1990 2^00 NO SQUEEKS» PLEASE! A JUMP TO WHEREVER YOU NEED TO RETURN IN THE N EX T ..YOUR RETURN LINK GOES AL 33 JMP HERE 1780 • 1790 PDA CAB2 C4B3 BOI l BOÏ ° BOI 0 BOI 4 3015 B9I6 89A 1 F 2A 2 F 4A3 FRA4 F7A5 TIFF SHED CLOUD # DID THE CONDUCTOR ..FLAG US DOWN? QUITTIN' TIME NO * THEN HIGHBALL DU nw DW DW DV DU DW DU DU DW DW DU DU NOP EGU PUT YOUR DATA READY FLAG HERE 0CCO0H 10 01 H 5D 1OH 207 EH 0 A 28 H 19 0 A H 0A0AH 5 3 0 AH 3939H 205DH ?0 06 H 2D 1 1H 2 0 1 1H PD 6 FH 206FH 191 OH SMOKE CHARACTER CAB DESCRIPTION ft ft ft ft BOILER DESCRIPTION ft ft ft ft ft f* ft ft ft ft FRAME DESCRIPTION ft ft ft ft ft ft ft ft TIES DESCRIPTION THIS IS SHED AREA 3*0172H BEGINNING OF CLOUD • * 11A00£fl<>!<*AFD‘i<CH;>l84<M$!100í*P3$20*3f,eAFA3CÍ>fc90021F7í»2l 10000C60E0B î 1AP01 A00Cn3w<Jif!i 1PB0P060CCD50001 13P0C0609CD5000 ! 134000604005060 ! 1A 0? 34 ¡¿pi001 l3B00P€0î»CD5«001 13C000601GD50001 13S00P6P lCF)52M*.f!C39A • 1A 0 0 4 F 0 0 K 9 0 0 l < ) 3 6 6 F ? 3 0 5 C í > ? 1 0 0 C 9 ñ l A 6 0 4 3 6 1 6 2 Í A B 0 4 3 6 0 7 2 l A B 0 4 3 6 6 E E 7 î 1A00630'3?A6601?5?AS04?A6301?.?B0042A6A0 l2"32042A6C0122E5C42A6E09 : 1A 0089000122E704 2 A 7 0 0 122E90422EBP42A72?1?2ED042A740122EF042A0D î1A009C007€0122F104Pa7801??24052A7aP122?605222305222A05?A7CP1c>5 l1A003600?2?C0Ç?A7S0|2?2E0P?A800122300501DFFF21620536190323AF52 : 1A 0 0 D 0 0 0 A P C 2 C 3 0 0 ? 1 0 0 C C E e 2 l 8 4 0 l 7 E 2 3 * £ B 7 7 2 3 7 C E B F E D 0 C 2 O 3 0 0 C D E D 0 0 B 1 • 1A00EA00C3D40001400JCSCDFF00CO3F01C10BAFA3C7F300C9210!CCtfÇD049 î1A0104007E2B7723237C89C90401C92100CC7S?3FE06C212F1?37EFE11C2DD : 1API15003 1011172140Ç077200CA520123732305C22501FE14C23C01112D5C : U01330013C323P1FE13C24701 1 15F 12C3230 IFF. 12C? 14P 1 1 12D1 1C32301PC : 1A015200013R0B03D300F 64 0G26 3P 1AFA3C2550IC9C360E00110175D7E2P46 : 19016C0C*280A04Ít>*APA¡*4'3-l39395D20062fll l2Ql 1206F2D6F2C 19 19C0C-3 11 HCC Newsletter/Vol. 2, Issue Il-12/D ecem ber 10, 1976 T A B L E OF CONTENTS PAGE HOM EBREW COMPUTER CLUB M EETING S R andom D ata, R obert R eiling..................................1 One M an’s System , Charlie P a c k ............................. 1 Wisconsin Area Com puter Society, R obert Reiling............................................. 2 G etting The Most O ut Of Tiny BASIC, T om P ittm a n .................................................................3 Inexpensive Graphics, W orkshop.............................3 A bout Reconnecting the IMSAI Power Transform er, Dave K inkade.......................................3 How I Built My First C om puter, Norman Walters............................................................4 Tiny BASIC Or How My Fam ily Came To Love My Com puter, Ray B o a z ............................... 5 Bulletin B oard ........................................................... 5 Stand-A lone A dapter F or VDM-1, Lee Felsensteiri.............. . 6 G ordon French’s Choo-Choo T ra in ........................ 8 Where & When The H om ebrew C om puter Club m eets a 7 p.m . at the Stanford Linear A ccelerator Center Auditorium . Dates scheduled for the rem ainder of this year are D ecem ber 10 and 22. The date and location are subject to change. If a change does occur, every effort will be m ade to provide ad vance notice in the New sletter. s £ R r a f r e e w a y <280 ) > C L Æ IU L IB E R 7 V HOMEBREW COMPUTER CLUB NEWSLETTER P.O. Box 626 M ountain View, CA 94042 L M BAKER DPT OF BIO. SCIENCE STANFORD UNIVERSITY STANFORD, CA 94305 C\AsS HCC N ew sletter/V ol. 2, Issue 11-12/D ecem ber 10, 1976 12