Oldskooler Ramblings

the unlikely child born of the home computer wars

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Happy 30th Birthday, Peanut

Posted by Trixter on March 23, 2014

While the announcement for the IBM PCjr was made in November 1983, it didn’t actually show up on store shelves until March of 1984.  So, I consider this week the official-unofficial 30th birthday of the IBM PCjr.

The Register agrees, and posted a very nice stripdown of the system, with sarcastic and humorous comments.  The comments section for that article also has some nice observations for those who would like a trip down memory lane.

Later this year I will record the full version of my PCjr talk that I was never able to fully give last year (floods, shortened timeslots, etc.) and I’ll break it up into parts and put it on youtube.  I’ll announce when that series is up.

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Where’s Trixter?

Posted by Trixter on February 26, 2014

2013 was somewhat challenging for me, but I have great hope and plans for 2014.  It’s only February and I’ve already spent some time at the ICHEG consulting for them on one of their projects — a validation of my electronic game history and preservation work, and a huge confidence booster!  I can’t speak highly enough of them, but I will try to do them justice in a future post.

Where can stalkers find me this year?  I’ll do my best to be at both NVScene 2014 in San Jose, CA the last week of March, and I’ll do my best to be at @party 2014 in Cambridge, MA in June.  Look for the grossly overweight 6’2″ scener wearing a black T-shirt with a huge yellow Hornet target on his back.

Preservation plans this year include writing a DOS-based search-as-you-type interface for a curated collection I am involved in.  Not impressive?  The DOS front-end has to run on any system with a hard drive — let’s see YOU implement a realtime search-as-you-type interface on an 8088 CPU in 512K of RAM with a hard drive that can do about 6 seeks a second.  I already have an idea on how I can pull it off, and if I can, it will be a huge win for enthusiasts and exhibitors with a vested interest in this material.

This year is the 10th anniversary of 8088 Corruption, which hasn’t been lost on me.  Expect a future post covering 8088 Corruption in some more detail with an encoder or two leaked.  Also:  I’m working on the sequel.  What could a sequel possibly be, since the original is a one-trick pony?  Well, how about video in graphics mode, which I originally said was impossible?  I think I can do it, still a on a 5MHz 8088 CPU, still a CGA card, still in color (although the initial demonstration might be in grayscale while I work out the kinks).  Actually, I’m already doing it — in my head.  It’s designed and tested already; I just need to convert what’s in my brain to source code.

Hobbies should always be secondary to things that really matter.  Good things are happening with my family as well:  My sons are improving at school (and in life in general), and life with my wonderful wife continues to improve.

Things are really looking up this year.  It’s about goddamn time, too.

Posted in Uncategorized | 10 Comments »

The IBM PCjr Exhibition Starter Kit

Posted by Trixter on October 3, 2013

I had a blast at this year’s VCFMW.  If you peruse my event photos, you’ll notice a PCjr setup in several pictures, both with and without people using them.  This was my display, which I pimped with an hour-long presentation about the history, hacking, and homebrew state of the PCjr.  I stood up three systems:  A starter (stock) system, an expanded system, and a hobbyist/homebrew system.  All had games and books and software, with original boxes and manuals.  I also laid out some cartridge games so people could see what those were like, and also some uncommon sidecars including a speech adapter and cluster adapter.  Finally, each monitor had a sign on top of it that encouraged people to TRY ME! and listed things they could do with each system.

All in all, I was pretty happy with it — and some others were too, based on the attention it got.  Some highlights:

  • Dads and sons playing Dr. J and Larry Bird go One-on-One against each other
  • A Lode Runner expert playing for over an hour through level 32 and 192,000 points until she had to leave
  • A couple of friends completing King’s Quest (using an iphone to download maps and hints)
  • The guy who made Coverfire (Crossfire clone) playing the original Crossfire on cartridge, like he had 30 years ago

People using the systems and asking questions was exactly what I was hoping for.

Missed the show?  Want to stand up an exhibit of your own?  Not to worry!  I’ve made all of my presentation and exhibition materials available under a Creative Commons Attribution 3.0 Unported License.  You are free to use those materials if you’d like to put on a similar presentation.  The 1-hour presentation slides, unprotected disk images for some games, signs I made for each setup, and even a PCjr button and t-shirt design are there if you truly want to nerd out.

Bill of materials

Starter system: 128k PCjr, no sidecars, wireless chiclet keyboard, two joysticks

Expanded system: Racore 2nd-drive expansion, 640k, wired “pro” PCjr keyboard (the later model), two joysticks.  (Optional: NEC V20 CPU, Tandy 1000 graphcs hardware mod)

Hobbyist system: jrIDE sidecar (adds hard drive via an 8GB IDE DOM, 768K RAM, clock), parallel-port sidecar with xircom PE3 adapter connected to the internet, IBM 83-key keyboard connected via a Racore adapter


I copied some software to diskettes (that I wouldn’t care if someone walked away with them) to demonstrate the starter and expanded setups:

  • Super Boulderdash
  • Jumpman
  • Dr. J and Larry Bird go One on One
  • Music Construction Set
  • Pinball Construction Set
  • Flight Simulator v2.12 (v2.13 has a bug if you try to use expanded memory)
  • Touchdown Football
  • King’s Quest (original PCjr booter)

These game choices were carefully considered and deliberate:

  • All of these were bootable disks that didn’t require any DOS — just insert the disk and turn on the system.
  • They all have support for PCjr graphics, sound, or both (Touchdown Football even talks!).
  • They support gameplay through joysticks which means there is no learning curve in figuring out the keyboard commands

I felt they showed off the “best intentions” of the PCjr while keeping user learning/confusion to a minimum.


To flesh out the display, I added many more materials: PCjr magazines, books, and original boxed PCjr-specific versions of software (Lotus 1-2-3, Wordstar, Typing Tutor III, Andrew Tobias Managing Your Money, others).  I wanted users to get a sense of what personal computing was like back in the 1980s and I felt the additional materials helped.  On more than one occasion people were flipping through the magazines, either looking for names they knew, or mocking some of the advertisements :-)

Here’s what it all looked like when completed:

1-20130927_184813 2-20130927_184819 3-20130927_184825

I will eventually be putting almost two hours of PCjr materials on youtube in a series of videos, but until then, enjoy the starter kit.

Posted in Uncategorized, Vintage Computing | 4 Comments »

Hey, a podcast appearance

Posted by Trixter on September 23, 2013

I had a great time talking with Anatoly of the DOS Nostalgia Podcast a few days ago, and what do you know, I’m capable of speaking into a microphone.  We spoke mostly about the first decade of PC gaming, and conclude with some games that were notable for being so well-programmed that they perform some amazing things on your 8088 that it really has no business doing.  Snag the episode here, and let him know what you think.

Posted in Gaming, Podcast, Uncategorized, Vintage Computing | Leave a Comment »

Access Software’s Echelon

Posted by Trixter on September 7, 2013

Someone with a lot more patience and dedication than myself reviewed a game that I always felt should have some sort of coverage: Echelon.  It’s one of those games that was more of a tech demo than a game, a phenomenon that occurred often in the first 20 years of personal computer gaming.  Echelon was essentially Access flexing their programming muscles, first with a 3-D flight sim and, in a later revision, continuous digitized sound and speech from the internal PC speaker (on any 286 or higher, otherwise it pauses the system while audio is playing).  They loved this idea so much that Mean Streets was originally going to be a spiritual sequel to Echelon, with a better flight sim.  Thankfully, Mean Streets also had an adventure game built around the flight sim that was much more enjoyable, so that’s why subsequent games are known as Tex Murphy adventures and not flight sims.

Gemini’s review of Echelon is likely the only review anyone will ever see of this game, so I recommend you check it out.  And the next time you have a rainy day you should also check out the other 120 (!) episodes of his DOS-era game review show Ancient DOS Games.

Posted in Gaming, Uncategorized, Vintage Computing | Tagged: , , | Leave a Comment »

PCjr talk cancelled

Posted by Trixter on April 18, 2013

Our basement flooded due to Illinois floodrains. I will not be traveling to notacon; there will be no PCjr talk this weekend.

Posted in Uncategorized | 4 Comments »

Anthropomorphising Computers

Posted by Trixter on December 4, 2012

A recent comment on a Slashdot story actually got me to laugh out loud at work enough to attract some attention, and that’s pretty rare for me (laughing at something I see on the internet).  What got me to laugh?  Human characterization of a computer.  It makes me laugh because I do the same thing — I give machines personalities when I think about or work with them.  (To those researching autism spectrum disorders, you might want to scribble something in your notebook right about now.)

Most people trying to comprehend what this is like would probably imagine something flamboyant and animated, such as Eric Schwartz’s tribute to the Amiga.  While such characterizations are creative and nice, that’s not what gets me laughing.  What does it for me is a computer that acts like a fallible human.  Here’s the post that got me laughing, paraphrased slightly (for the uninitiated, ext4 is a method of storing files in a Linux system, and the context is an application “talking” to the operating system):

I don’t quite trust ext4 for writes.

app: Hey, can you write this data out to
ext4: DONE!
app: Uhh, that wasn’t long enough to actually write the data.
ext4: Sure it was! I’m super faGRRRRRRRRRRRRRst at writing too.
app: Wait — did you just cache that write and report it written, but then not actually write it to disk until 30 seconds later?
ext4: Yeah, so?

I routinely do this sometimes when dealing with a unix server that is hurting, such as having so many spawned threads due to an unforseen condition that there are several times more threads running than there are CPUs to handle them.  I imagine each CPU as a juggler frantically trying to keep 20 pins in the air at once, sweating profusely, and calling out to the other CPUs for help only to have them yell back they are just as screwed as he is.

Does anyone else do this, or is it just me?

Posted in Sociology, Uncategorized | Leave a Comment »

A Quick Vignette

Posted by Trixter on September 16, 2012

My 12-yr-old recently wanted to purchase something truly stupid, expensive, and transitory with his hard-earned money, and rather than try to convince him otherwise, I went ahead and let him.  Being disappointed with a purchase is something I would rather he learn sooner than later, so he can start making good decisions quicker.

I was not as lucky.  I bought some real crap in my time (the name Emerson should strike fear into everyone’s heart) and while it taught me to stop buying cheap crap (stuff that broke, stuff that was disappointing, etc.), it took longer than it should have.  My most cringe-inducing purchase was a Miami vice-like outfit the summer before high school (this is summer of 1985 for those wishing stage public humiliation – it’s okay, I don’t mind).  I put it on and walked nearly 2 miles to a party some girl I thought I had a crush on was throwing.  I thought I was going to be hot shit, but as I approached the outdoor party, everyone laughed at the Miami vice thing since it was cheezy (and I was in Illinois, not California).  Seriously, I had not even reached the front door when I’d gotten my third uncomfortable comment… so I kept walking, never stopped, turned the corner and came home, another 2 miles.  My grandmother was house-sitting at the time, and she saw me come in the front door less than an hour after I’d left, and wisely didn’t say anything.  I took off the outfit, hung it up, and never wore it again.

I should have thrown it away immediately.  It might still be in the closet in the house I grew up in.

Posted in Family, Uncategorized | 3 Comments »

2011 in review

Posted by Trixter on January 1, 2012

The WordPress.com stats helper monkeys prepared a 2011 annual report for this blog.  While I’m dismayed that most people who came here were looking for Jeri instead of me :-O it’s still not bad for a slow year.

Here’s an excerpt:

The concert hall at the Syndey Opera House holds 2,700 people. This blog was viewed about 48,000 times in 2011. If it were a concert at Sydney Opera House, it would take about 18 sold-out performances for that many people to see it.

Click here to see the complete report.

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At a disadvantage

Posted by Trixter on June 4, 2011

Quick, without doing any research: What early 1980s computer was faster, the IBM PC or the Commodore 64? The IBM PC ran an 8088 at nearly 5MHz, whereas the C64 ran a 6502 variant at 1MHz. The PC cost thousands of dollars, the C64 hundreds. The PC had a 1 megabyte address space; the C64 only 64K. Is this a trick question?

It is!  The C64 was faster.  The original IBM PC, despite appearances and bias on the part of both consumers and marketing, was actually the slowest popular personal computer on the market at the time of its release, even compared to the Apple II and Atari 400.  Here’s why.

The 8088 holds an uncomfortable position between the realm of 8-bit and 16-bit personal computing; while the internal word size was indeed 16-bit, the 8 in 8088 means that its external data bus was only 8 bits wide.  This means that the 8088 could only access one byte of data in a single bus operation, giving it speeds much more like an 8-bit personal computer than a 16-bit one. Normally this is no big deal; the 6502 used in the C64 had the same limitation.  But unlike the 6502, which could access a byte in a single cycle, the 8088 took 4 cycles to access that same byte.  Another way of looking at this: every time memory is touched, the 8088 wastes 75% of its cycles, effectively turning the IBM PC from a 4.77MHz computer into a 1.1925MHz computer.  This gave it a “lead” of only 0.1695 MHz over the C64.

If it still had a slight lead, then why was it slower?  While the 8088 could indeed operate on 16 bits at a time, the machine instructions were between 2-4 bytes large, and only the simplest instructions took 2 cycles to execute.  Contrast that with the 6502, where most instructions are 1 byte large and most execute in 1 cycle.

Let’s illustrate this with a fun example:  Rotating a byte of memory once using ROR (rotate right). We’ll keep it fair by treating the PC like it only has a single 64K segment of memory. First, the 6502 version using ROR:

Cycle Operation
1 fetch opcode, increment program counter
2 fetch low byte of address, increment program counter
3 fetch high byte of address, increment program counter
4 read from effective address
5 write value back and do operation
6 write the new value to the effective address

6 cycles. Now the 8088 version:

Cycle Operation
1 ROR BYTE PTR [1234],1 expands to “D0 0E 34 12″ so let’s get to fetching the opcode:
2 (still fetching…)
3 (still fetching…)
4 (still fetching…)
5 (still fetching…)
6 (still fetching…)
7 (still fetching…)
8 (still fetching…)
9 Fetch lowbyte of address
10 (still fetching…)
11 (still fetching…)
12 (still fetching…)
13 Fetch hibyte of address)
14 (still fetching…)
15 (still fetching…)
16 (still fetching…)
17 Perform operation, which takes 15 cycles + EA calculation (6)
37 Final cycle of calculation, we’re done, yay :-/

What took 6 cycles on the C64 takes 37 cycles on the IBM PC, no thanks to the slow memory access of 4 cycles per byte. Taking both machine’s clock speeds into account, this means the operation takes about 6 microseconds on the C64 and about 8 microseconds on the IBM PC.  It can get much worse than that, especially if you’re foolish enough to access more than a single 64K memory segment.  IBM PC is teh suck! (*)

The gap between the IBM PC and the Atari 400 is even wider, if you can believe that, because the Atari 400 ran the 6502 faster (1.78MHz) than the C64 (1.026 MHz).  The BBC Micro?  2MHz!  It’s painful to think about!

Ever wonder why there hasn’t been a true demoscene demo on the original IBM PC aside from three scrollers (all Sorcerers releases, btw)? Well, now you know one major reason. (Lack of decent graphics is another; in fact, I’d be willing to argue that only the Apple II had slower graphics.)

(*)Yes, I know the 8088 has 4-byte prefetch queue that sometimes speeds things up.  That comes in handy, oh, almost never.

Posted in Demoscene, Programming, Uncategorized, Vintage Computing | 33 Comments »


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