Oldskooler Ramblings

Today’s post over on Vintage Computing and Gaming’s Retro Scan Of The Week covered the magazine Family Computing, one of the lesser-known personal computing magazines of the 1980s, which brought back a memory that I think is important to share.  Normally I’d write a lot of historical info about Family Computing Magazine itself, but not today.  This post is less about Family Computing and more about how a simple choice my father made shaped my life.

In 1983, having started using the Apple IIs at my school for word processing and simple programming with LOGO, I became quite interested in computers and really wanted one, but our family didn’t have a lot of money at the time and couldn’t afford one, even a C64. My father was sympathetic to how I felt, and as a small consolation bought me a subscription to Family Computing Magazine. It turned out that the magazine subscription was just as valuable a gift as the computer I wanted. Whenever it arrived, I read it cover to cover in 2-3 hours, absorbing everything in that magazine and learning about every system on the market as well as what kinds of software and hardware were available for them.  More importantly, I also learned what other people were using their computers to accomplish, far beyond a simple checkbook balance or playing a game.  And for those specialized tasks, they were often writing their own software in BASIC.

That’s a nice memory, but not a life-changing one.  What changed my life, specifically, was the combination of three things:  My desire to use a computer + not actually owning one + the BASIC listings in every Family Computing magazine.  Every mag had a few BASIC programs that did various things, usually a utility program, a simple game, and some “mystery” program that displayed or printed some graphic or message and you had to run the code to see what it was.  They were written in Applesoft BASIC, with diffs for other computers of the time (usually Atari 8-bit, C64, TRS-80, and TI 99/4A were represented, with later diffs for Spectrum and PCjr’s sound and graphics).  Because we didn’t own a computer, I would spend hours tracing through the BASIC listings in my head to “run” them to see what they did.  Sometimes I had a pad next to me to jot down notes, as I couldn’t juggle more than 5-6 variables at a time. For the “mystery” programs that output graphics, I would plot the output on graph paper.  Each program was a puzzle to solve.  My brain became an emulator.

Dad saw me spend hours reading each magazine, and going over older ones, so he found a way to save monthly for a computer.  A little over a year later, he surprised the family with an AT&T PC 6300, which he was able to get at a discount because he worked at AT&T at the time. I nearly exploded, and barreled through that machine with a purpose.  I used that computer just as long as I read Family Computing, both until roughly 1989.

Today, I program in 8088 assembler for fun.  It calms me down.

Thank you, Joey Latimer, for writing all those BASIC programs, and thank you Dad, for a simple act of empathy.

I have a friend named Andrew Jenner.  If you’re intimately familiar with PC retrocomputing, you may remember him as the person who thought it would be a good idea to remaster an old game called Digger so that it could be recompiled for modern machines/languages/operating systems.  Meaning:  He took the original game binary, used DEBUG.COM to dump sections of it out as partially-assembled assembler source, and examined and tweaked it over several months until it could compile back into the original.  Then he translated that into C.  Then he made the C portable.  Then he made the C portable across operating systems.  Then he switched out the graphics for higher-resolution ones.  The end result is that you can now play this ancient game perfectly on any operating system, even in a Java VM.  His actions inspired similar projects by other people, like The Jumpman Project and The Beyond Castle Wolfenstein Project.  So that’s what Andrew does for fun.  At least, that’s one of the things he does for fun, when he’s not building new electronic music toys for his children, or writing a cycle-exact 8088 emulator, or just generally visiting every single hackerspace in a 200-mile radius to kick down the door and show them who’s boss.

He wrote me recently to let me know he had purchased an XT to do some democoding on it, a shared passion of ours.  It came with a monochrome card, but he lacked a suitable monitor; it also lacked a keyboard, and a working disk drive.  Did that stop him from using it?  Hell no, this is Andrew Fucking Jenner!  Step aside, son:

I ordered a CGA card but decided to see if I could jerry-rig something up in the meantime. I programmed my Arduino to pretend to be an XT keyboard and also the “manufacturing test device” that IBM used in their factories to load code onto the machine during early stage POST (it works by returning 65H instead of AAH in response to a keyboard reset). I then used this to reprogram the CRTC of the MDA to CGA frequencies (113 characters of 9 pixels at 16MHz pixel clock for 18 rows (14 displayed) of 14-scanline characters plus an extra 10 scanlines for a total of 262 scanlines). The sources for this are on github.

I had to re-read that a few times to make sure I wasn’t having a seizure.  Let’s confirm what happened:

1. With no input device or working disk drive, he still managed to load code by reprogramming a microcontroller to emulate a long-forgotten IBM diagnostic protocol, formerly used only in factories by test devices to QA units before they went out the door.
2. The code he loaded was to force a monochrome card to output NTSC signals, so that could be connected to a TV.  Not dramatic enough for you?  How about this:  He forced a monochrome card to behave like a color card.
3. He made the schematic and source code available, because that’s the kind of guy he is.

You don’t mess with Jenner.  You do read his blog, however.