No. 42 July/ August 1988 $3.95 T H E M J 0 U R N A L Maintaining PCs Keeping Your Hard Drives Running page B Lose your hard drive and you're losing a lot more than $500. You're losing data. Troubleshooting PCs page 14 Finding the defective IC is usually easy if you know what you're looking for. XT Theory Of Operation page 24 It's a lot easier to make sense out of a problem if you know how the circuit works. Simulating A Bus page 32 Once we have the system running we may as well observe something with it. Plus: Ray Tracing (Part 2) page 18 West Coast Computer Faire page 40 Inside PCX Graphics Files page 42 Testing Your Product Idea page 67 And Much, Much, More 1111111 0 . I - . 7~ II , I l,19 Al 31 _. '. CASES & KEYBOARDS POWER SUPPLY 5339 Professional XT-AT 150 Watt Power Supply (XT). 50.00 w I 12 function key 69.00 200 Watt Power Supply (AT). 80.00 5060 Keyboard AT Style .. 55.00 XT Slide Case . 34.00 KB101 Keytronic. 67.00 XT Flip Top or XT Slide with Lock & LED . 38.00 AT with Lock & LED. 65.00 Free Instructions with Each System MONITORS EGA/CGA (Auto Switch) . .. .. 452.00 HARD DRIVES VGA/EGA/CGA Color .. ..... 600.00 & CONTROLLERS CGA Color. .. 295.00 AT 40 MB Seagate #251-1. ..445.00 Amber 12" TTL . 89.00 AT ST 4053 HD. .545.00 Green 12" TTL .. 89.00 AT (MFM) Hard Drive & VIDEO CARDS floppy controller (WO). .140.00 AT RLL HD & FD controller . Color /Graphics/Parallel . 52.00 . .. 189.00 - Pictured keyboard is 5339 - 20 MB Miniscribe HD 256K EGA Graphics. .. 125.00 with controller . Mono/Graphics/Parallel .. 49.00 KIT OPTIONS . 349.00 A Tl Graphics Solution- *MS DOS 3.21or3.3 w/ 30 MB Miniscribe HD OW Basic . 95.00 with controller . ..369.00 Mono, Herc. Color Emulation on *5339 Keyboard Sub ...........•.... 24.00 Mono CGA ........... (List 299) 125.00 *Color Options: SOFTWARE ATI Wonder Auto Switch Mono, Herc (Includes video card & monitor) The Twin Spreadsheet 49.00 CGA Color . 200.00 CGA, EGA, VGA Leading Edge Word Any monitor, Any software, Auto conversion CGA/EGA Color ................ 410.00 CGA/EGA/VGA Color .......... 590.00 Processor .. 49.00 . (List 499) 299.00 ASSEMBLY AND TESTING Ventura Desktop EGA, CGA, VGA (640x480) . .185.00 XT Systems . 60.00 Publisher by Xerox . .. ... 525.00 AT /80386 Systems ................. 80.00 EXPANSION CARDS Learning Dos-MicroSoft ..... 45.00 Clock Card. 25.00 XT KIT WI 2 Floppy Drives. ACCESSORIES Dual Floppy Disk Controller . 25.00 Includes: 0K RAM, Serial, parallel and game 1200 Baud Modem - Internal Joystick . 25.00 portS, clock/calendar, AT-Style keyboard, cabinet, (Leading Edge Model L) Gravis Analog Joystick . 49.95 power supply, mono graphics card and amber or Hayes compatible . 99.00 green monitor. Keyboard switchable turbo. Game Port 19.00 2400 Baud Modem - Internal 8 mhz with lock, LED, Reset Multi-Function, 1 ser/par/clk/game/ (Leading Edge Model L) & Turboswitch ............. 579.00 2 floppy . 61.00 Hayes compatible ........ 219.00 lOmhz with lock, LED, Reset Parallel (printer) . .. .. .. .. .. .. 19.00 1200 Baud Modem - External & Turboswitch ......... '.... 599.00 Dual Serial Port Card - Hayes compatible .. ..119.00 1 installed switchable V20-8mhz ..... 14.00 Com l,2,3,or4 .. 29.00 XT KIT W /20MB Hard Drive. Memory Chips . ... (call for prices) Kit for 2nd Port 20.00 Includes: 0K RAM, Serial, parallel and game 640K RAM (0K installed). .. ... 35.00 ports, clock/calendar, AT-Style keyboard, cabinet, DEPEND ON MICROSPHERE power supply, mono graphics card and amber or The components and products we sell are green monitor. Keyboard switchable turbo. chosen specifically because they have been proven 8 mhz with lock, LED, Reset Prices are subject to change without notice. in our own use and testing. We guarantee our & Turboswitch ............. 879.00* Shipping CHARGES will be added. cards will be compatible when purchased all lOmhz with lock, LED, Reset & Turboswitch ............. 899.00* together. 1)' *(For 30MB Miniscribe add $50.00) ~\$"€. N£,"\}J "'-£, BUILDING YOUR MOTHERBOARDS 80386 KIT- \. OWN CLONE XT/Turbo 4.77 /lOmhz. .. ... 109.00 Includes: 8/16 mhz, lMB RAM, 1 360K floppy ****FREE BOOKLET**** AT 6110 mhz Choice of Award, drive, 1-1.2 MB FD, 1 40MB HD, Award bios, *90-day warranty/30-day money back Phoenix or DTK Bios . .. 350.00 switchable keyboard, monochrome monitor, mono­ (subject to restrictions) XT /Turbo 4. 77 /8 mhz .... 99.00 graphics. Serial/parallel ports, case, power supply, 80386 8/16 mhz/ Award Bios & game port, clock/calendar. Main board made in U.S.A. lMB RAM, made in U.S.A. .... 1595.00 2675.00 ~MicroSohereNC For XT I AT memory. ... $Call ~COMPUTERsr. FLOPPY DISK DRIVES 80286 .. AT KIT Includes: 0K RAM, 1.2 MB FD, 1 360K floppy MicroSphere, Inc. Fujitsu 360K. 89.00 drive and 40 MB Seagate St 251 hard drive, Toshiba 360K .. 99.00 61 lOmhz, serial, parallel and game ports, clock/ P.O. Box 1221 Teac 1.2 MB . .. 125.00 calendar, AT-style keyboard, cabinet, power Bend, Oregon 97709 1 supply, monographics card, amber or green (503) 388-1194 •.z: Toshiba 3 /z" Drive Kit 720K .. .125.00 monitor, keyboard switchable turbo. Toshiba 3W' Drive l.44mb .... .. .. 145.00 Hours: Monday-Friday 1495.00 9:00-5:30 Reader Service Number 2 2 MICRO CORNUCOPIA, #42, July-August 1988 T H E MICRO TECHNICAL J 0 U R N A L MICRO CORNUCOPIA JULY/AUGUST 1988 - ISSUE NO. 42 FEATURES COLUMNS David Thompson 50 C'ing Clearly 8 Keeping Your Hard Drives Running Scott Ladd looks at two exciting new C packages, one Think you're taking good care of your hard drives? Really? from Zortech, the other from WATCOM. You're covered for every possible problem. Right? Ok, go ahead and ignore this article. Make my day. 56 86 World Dan Evans & Don Doerr Laine leaves the U.S., his 286 system under his seat and a 14 Troubleshooting PCs and XTs giant screen on his mind. (66 lines anyone?) Chip-level troubleshooting doesn't have to take days. 64 ShareWare Ten minutes is their max. Ear I Hinrichs 67 On Your Own 18 Ray Tracing on the Tl34010 (Part 2) 70 Pascal Column If you're interested in graphics or just puzzled about solving quadratic equations in assembly language, then this is your dimension. 75 Culture Comer Larry Fogg 24 XT Theory Of Operation 86 Technical Tips Larry thought he was done after he finished the last of the XT's smart chips. However, you don't have a computer without pasting a few of these guys together. CP/M CORNER Bruce Eckel 32 Simulating A Bus 83 CP/M Notes If you're really interested in getting your computer off its digital jag and into the analog world then this bus based A/D 84 Kaypro Column Y1 project is a great start. 5-3e pF 14.31818 MHz R2 519 David Thompson READY FUTURE TENSE RES 1S RESET 40 The West Coast CLK88 Computer Swap Meet 4.n MHz After missing the Faire for six 72 Tidbits years I was very surprised. PCU< 96 Last Page Sam Azer 42 Working With PCX Files This is a sneaky article. To understand graphics file formats you need to understand how graphics are displayed, Cover illustration by Paul Leatherwood especially color graphics. Sam explains both. MICRO CORNUCOPIA, #42,July-August, 1988 3 By David Thompson THE MICRO TECHNICAL JOURNAL MICRO CoRNUCOPIA Editor and Publisher David J. Thompson The West Coast Associate Editors Gary Entsminger Computer SOG Cary Gatton Technical Department Larry Fogg Director of Advertising & Distribution Jim Warren, founder of the West Coast Computer Laura Logan Faire (and wearer of the skates) will be joining us in Bend this summer for SOG VII. You too can join him for Accounting rafting, desktop publishing info, sessions on how-to ser­ Sandy Thompson vice drives and systems, Al, C++, SCSI, the latest from Intel, compiler writers, a technical book author, and (of Order Department course) much, much, more. Sign up for the Saturday Tammy Westfall evening banquet and you'll hear Jim ask the burning Graphic Design question: ''When are we going to do something useful Carol Steffy with microcomputers?11 Don't wait to send in your registration. We're look­ MICRO CORNUCOPIA (ISSN 0747- ing forward to seeing you in Bend July 14-16 for what's 587X) is published bi-monthly for $18 per going to be the biggest, most informative, most laid­ year by Micro Cornucopia, Inc. 155 NW back Semi-Official Get-together (SOG) ever. (Held again Hawthorne, Bend, OR 97701. Second-class at the Central Oregon Community College campus.) postage paid at Bend, OR and additional Last year's attendees told us they'd gotten ten times mailing offices. POSTMASTER: Send ad­ as much out of SOG as they got out of those $300+ con­ dress changes to MICRO CORNUCOPIA, PO Box 223, Bend, OR 97709. ferences their employers were sending them to. At SOG they not only learned much more, they (and their SUBSCRIPTION RA TES: families) enjoyed it immensely. 1 yr. (6 issues) $18.00 2 yr. (12 issues) $34.00 Added Attractions 3 yr. (18 issues) $48.00 During SOG, Bend will be hosting the Cascade Cy­ 1 yr. Canada & Mexico $26.00 cling Classic. The Classic has been on the bicycling tour 1 yr. Other foreign (surfaca) $36.00 for many years and attracts the top professional teams.