Note to self:
"I do not need to build an AY-3-8910 out of discrete logic chips."
"I do not need to build an AY-3-8910 out of discrete logic chips."
"I do not need to build..."

https://github.com/mengstr/Discrete-AY-3-8910

But how cool would that be!

#AY38910 #RetroComputing

mTCP NetDrive users ... I have new test code available that really makes things fly, especially on remote connections.

My 386-40 saw speedups of 1.4x to 2.7x when talking to a server on the same network, and 12x to 21x when talking to a remote server.

Help me test it ... more details at: https://groups.google.com/g/mtcp/c/wRvAOsHUkwg

#retrocomputing #dos

The existence of #MSDOS implies the existence of MS-UNO.

#retrocomputing #shitpost

Is this one of those "Soundblaster or 100% compatible" devices the cool kids are always talking about?

#retrocomputing #soundblaster

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A picture of a USB DAC that is branded as "Creative Sound Blaster"

Thank you to UW for inviting us to TGIF at the Paul G. Allen school for Computer Science and Engineering. The MITS Altair 8800 running Microsoft BASIC was a hit. #retrocomputing #vintagecomputing https://icm.museum

We’re at #norwescon48 at the SEATAC double tree today and tomorrow #retrocomputing #vintagecomputing

VCF PNW 2026 is just a month away!

https://vcfpnw.org/

May 2nd and 3rd, Tukwila, WA (just south of Seattle near the SEATAC airport).

Sponsored by the Interim Computer Museum.

#retrocomputing

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VCF PNW 2026 Advertising Flyer

Early IBM PC compatible architecture is the worst. The time of day is maintained by interrupt processing, which can be disrupted by an excessive number of interrupts, like when receiving network packets. The machine loses time when it gets flooded, making benchmarking network performance impossible without a stopwatch.

Later machines can read the CMOS clock to avoid this problem, and faster machines can keep up with packet flooding. But XT class machines are just bad.

#retrocomputing

KiCad is pretty useful for documenting pinouts, even if no actual circuitry is involved.

Here I have documented how the Warp Speed light pen for the IBM PC is connected, and how I wired up the Tandy 1000 adapter for it. Also the PCjr light pen header, because why not.

I'll just export this to PDF and include it with everything when I upload it to archive.org.

#retrocomputing

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A screenshot of Kicad's schematic view showing the various pinouts for the Warp Speed Light pen, from the cable to the adapter box and the Tandy 1000 adapter GloriousCow made.

I did find this cool advertisement for the Warp Speed light pen.

"CONTROLLER" is their DOS shell, and it's actually not terrible - I will be making a video demonstrating it later.

My driver disk came with CONTROLLER 2.0. Reviews at the time praised it, but that's about all the praise this thing got - the drivers for Lotus 1-2-3 and other software were a bit glitchy.

#retrocomputing

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A full page magazine advertisement. "The Warp Speed Light Pen. Works as Fast As You Think." Three photos of a CRT screen are shown with a disembodied hand holding the titular pen, doing spreadcharty things. A short list of software titles is also given as well as Warp Speed's 1-800 number.

Here's a student using another Warp Speed light pen, on a much newer computer than I would have figured would still be using a light pen.

Light pens, in 1995??

Also, she's a direct descendant of Geronimo. I can't say I was expecting that. You got me there, Light Pen.

Here's the article:

https://archive.org/details/IBMPersonalSystemsMagazine/PersonalSystems_1995_MayJune/page/n13/mode/2up

#retrocomputing

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A student in a classroom for Native American children operates a mid-90's IBM computer with a light pen.

Another fun project for the day. I'm debugging this PCjr which won't boot - no POST, not even a beep.

It looks like the 8284A chip is not toggling the RESET pin on the 8088, so it doesn't run. I replaced a capacitor that feeds the 8284A but that had no effect. I can get the machine to boot if I pull the reset line low by hand. (Composite output is corrupted but RGB output is fine.)

I just need to find a source for 8284A chips. It looks like used is the only option.

#retrocomputing #pcjr

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PCjr in pieces on the work bench being debugged. A analog o-scope is showing the CPU clock pin.

helpful tip

#retrocomputing

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a black and white diagram showing an isometric line drawing of a DIP chip in a socket, with several pins bent out of place. it is labelled "Incorrect chip installation"

Quality time using the Tandy Model 102 and a DVI (Disk/Video Interface) as a terminal to get on IRC.

My apologies to the Tandy fans, but these things make early DOS machines look like highly polished high-end systems. It's primitive, but it is also still amazing what they squeezed into 24 or 32KB.

The DVI is even more strange ... it's basically and entire other computer running a tiny OS to provide the diskette and screen handling functions to the main machine.

#retrocomputing

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Tandy Model 102 portable computer with a Disk/Video Interface and an Amdek 300 composite monitor.

TIL that the #IBMPC didn't come with just #MSDOS. It had *four* operating systems available from the start.

I imagine that's why it was designed to boot from disk, and not a fixed ROM operating system like the #Macintosh.

The four original IBM PC operating systems were:

* #ROM #BASIC
* UCSD p-System, an OS built around a #bytecode interpreter for #Pascal
* CP/M-86, an x86 version of #CPM
* #IBM PC #DOS, a knock-off of CP/M from a little-known company called #Microsoft

#retrocomputing

📰 ENIAC, the General-Purpose Digital Computer, Is 80 - IEEE Spectrum

｢ The computer contained about 18,000 vacuum tubes, which were cooled by 80 air blowers. More than 30 meters long, it filled a 9 m by 15 m room and weighed about 30 kilograms. It consumed as much electricity as a small town ｣

https://spectrum.ieee.org/eniac-80-ieee-milestone

#eniac #computinghistory #retrocomputing

Coding is contagious so I went back and did some more. Here are the current stats:

Test: Copy a 4MB file to a server that is 55ms away. (About 1400 miles.) The machine is a 386-40 running DOS 5 with an NE2000 card.

Old code: 220 sec, 18.6KB/sec

New: 17.14 secs, 238KB/sec.

Copying the file to the same local hard drive takes 4.84 seconds so the remote copy to a server is only 3.5x slower.

Next: improve the read speed so I can host the SIMTEL archive via a DOS drive letter.

#retrocomputing

I spent two long days coding streaming writes for mTCP NetDrive. I have some early results.

The test: Copy a large file (1.7MB) from a 386-40 with an NE2000 card to a Linux server about 1800 miles away.

Old code: 18KB/sec
New code: 214KB/sec

The new code is about 350 bytes larger and uses no additional memory on the client side. On the server side I just had to increase buffer sizes.

And DOS is none the wiser .. the remote server just looks like a drive letter.

#retrocomputing #mtcp

Happy International Pi Day! Celebrating the infinite possibilities of clean code and extreme portability.

What a better day to remind everyone: Of course it runs NetBSD! 🚩

#NetBSD #PiDay #PiDay2026 #OpenSource #RetroComputing #RunBSD #linux

@wbpeckham You probably already know this, but DOS didn't start with networking so everything is grafted on.

I'm a big fan of the "packet driver" approach, which loads a small device driver for your card as a TSR and enables the higher level applications using a published API.

Besides the packet driver, my code needs one-time configuration. After that run EXEs for what you need. That's pretty simple.

#retrocomputing #mtcp

Greetings fans of DOS networking! I'm working on bug fixes for mTCP. If you have a bug report or a feature request now would be a great time to let me know. Send it by email or ping me here.

So far I've done a lot of "code golfing" (making things smaller and faster). Telnet will have SIXEL graphics enabled and a few bug fixes. TCP has a flow control improvement to help with the occasional stall. And there are a few other small fixes so far too.

#retrocomputing #mtcp

The Legacy 8080 is an incredibly built IMSAIesque replica with enhanced features courtesy of @Dream_Library_ and now on display for use at https://icm.museum come see it march 28th - 30th in Seattle!

We will be bringing this to the upcoming events on our calendar this year.

#retrocomputing #vintagecomputing

#Retrocomputing #UNIX #SlowComputing

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Neofetch output showing the config: NetBSD 11.0 RC2, AMD 486-class CPU, 128MB RAM

#Retrocomputing #UNIX #NotAToaster

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Screenfetch output showing an Xterm window with the specifications of the machine: NetBSD 11, Intel 686-class CPU, R200-class GPU, 492MiB RAM (?)

#beer

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A glass of red ale (Spitfire) with a perfect head. The mug is from the Ottakringer brewery in Austria, and has a handle. There is a candle behind the glass which makes the beer glow amber. My reading glasses folded up next to it.

#RetroComputing #Desk #Clutter

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"Before" picture: A messy desk: From left, a black desktop PC (a 386), on top of it a open benchtable build with a dual Penitum CPU motherboard and various expansion cards. In the middle a display, to the right another open benchtable with no board installed. The desk is extremely cluttered with RAM sticks, various tools, paper stickers, various bits and bobs, scissors, cables and whatnot.

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"After" picture: Same as above, but all the clutter is gone, revealing a black desk, a white keyboard, a white and a black mouse, and not much else. The screen shows a NetBSD desktop with Windowmaker.

This is an oddball ... a Compex Paraport-ETP Pocket Ethernet Adapter. It attaches to a PC via the parallel port, making it a great solution for early laptops.

These are not very common compared to the Xircom Pocket Ethernet adapters. Luckily I saved the device drivers years ago. (They are still available for download too.)

On a PCjr it transmits and receives at 32KB/sec, which is good for a 4.77Mhz machine. The parallel port is the bottle neck here.

#retrocomputing

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Compex Paraport-ETP parallel port Ethernet adapter, with power cables designed to tap 5v from the keyboard port and the original carrying back.

Well, I went total DOSception today:
This is JS-DOS, an MS-DOS emulator for web browsers, running DOjS, my Javascript runtime for MS-DOS, running a p5js sketch written in Javascript.
Last screenshot shows the sketch running natively from OpenProcessing

#RetroComputing #JavaScript #DOjS #p5js #CreativeCoding #MSDOS #OpenProcessing

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a screenshot of firefox showing js-dos and a directory listing

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a screenshot of firefox showing a text mode javascript code editor

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a screenshot of firefox running js-dos with the emulator showing penguin like birds in different colors drawn by simple lines

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a screenshot of firefox showing the open processing website with penguin like birds in different colors drawn by simple lines

Unix 🤝 Amiga

｢ Amiga UNIX (also known as “Amix”) was Commodore's port of AT&T System V Release 4 Unix to the Amiga in 1990. Like many early Unix variants, Amiga Unix never became wildly popular, but it is an interesting sidestep in the history of the Amiga ｣

https://www.amigaunix.com/doku.php/home

#amiga #unix #amix #retrocomputing

Mhhh.. #snac crashes when it start's in my Dual Pentium II system. It's performing at start a heavy job "started deferred data integrity check", which does lot IO.
When I turn off the traffic from outside, it seems to run (takes ages). But when I turn on the traffic to it, it crashes with
`Illegal instruction (core dumped)`

I took the installation over from the PIII system and activated the MP #OpenBSD kernel. (Do you really have to cp it from the CD by yourself??)

#retrocomputing #retroserver

Installing DOS 5.02 on an IBM PS/1 donated to us by Free Geek PDX thank you FG!

#retrocomputing #vintagecomputing #ibm

Doing some maintenance on my cyber lair 🤪

#archlinux #manjaro #debian #RetroComputing #netbook

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A cluttered workspace featuring multiple laptops displaying various codes and commands. There are gadgets and equipment on shelves, spools of filament, and tangled wires throughout the area, indicating an active tech or programming environment.

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A cluttered workspace featuring a monitor, speakers, computer components, and a keyboard on shelves. Various electronic devices and a tangle of cables are visible, along with storage containers and tools nearby.

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A computer monitor displays four terminal windows with system information. including an output that highlights the Linux distribution and system specifications.