mbbrutman

Retrocomputing, DOS Networking (mTCP), yard work, and a few other things ...

Last Notes

2026-10-10 18:01:01 UTC

A new mTCP is available! This version is mostly a maintenance release, except for NetDrive which has some major improvements.
Downloads and release notes are at https://www.brutman.com/mTCP/mTCP.html.
Ping is more accurate. The HTTP server source code is now available. Telnet now supports black and white Sixel graphics. There are small bug fixes and improvements sprinkled everywhere.
NetDrive gets faster, especially on remote links, without using any additional buffer space.
#retrocomputing #networking

2026-09-22 16:07:14 UTC

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I firmly believe in doing my own work, including losing sleep because of long debug sessions and the occasional swearing. But I can claim that I understand the result, and I can maintain it and explain it thoroughly.
The people making AI creations, well, not so much. They are "productive", but they don't understand the details. They experience the joy of creation like a quick sugar rush, without the months of work behind it.

2026-08-28 19:35:46 UTC

Nothing says "Let's do business" better than a branded analog joystick:
#retrocomputing
https://mastodon.sdf.org/system/media_attachments/files/117/174/809/747/707/485/original/841a60db4106c871.png

2026-08-11 22:23:44 UTC

I installed Windows 3.11 for the first time today. Instead of shuffling floppies I used a DOS virtual machine to expand the install disks on a NetDrive image and then installed from that image.
Below you see Netscape Navigator using Trumpet Winsock, running on top of Winpkt.com and my DOS packet driver for the DaynaPORT SCSI/Link ethernet device. (It works on emulated versions and the real hardware.) The speed is not great under Windows, but it works!
#retrocompting
https://mastodon.sdf.org/system/media_attachments/files/117/079/194/487/267/208/original/dc2d897254b37f88.jpg

2026-03-16 23:27:51 UTC

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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

2026-03-15 21:37:40 UTC

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

2026-03-12 04:49:49 UTC

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

2025-11-02 06:31:21 UTC

Does anybody know how SCSI Ethernet adapters were able to signal the OS that a new packet had arrived and needed to be processed?
With storage devices and scanners the host issues a command first and the SCSI device responds. But Ethernet is different in that packets arrive asynchronously, and not in response to a host command.
Network adapters can use hardware interrupts to handle incoming packets. How did SCSI Ethernet adapters do it? Was polling the only option?
#retrocomputing #scsi

2025-07-25 01:17:11 UTC

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whoops... Link added to the post.

2025-07-25 00:33:13 UTC

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I dug out the source code and put a small HTML wrapper around it to explain it.
This version of the code is the last version, dating back to October 1988. It includes buffering blocks in RAM to avoid the performance problem with writing each 128 byte block to disk, and two different ways to cheat and abort a perfectly good transfer to avoid getting charged.
38 years later I'm proud of the cleverness, but not proud of the cheating. ;-)
https://www.brutman.com/leech/leech.html
#retrocomputing

2025-07-24 04:42:05 UTC

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I and a friend discovered this vulnerability in 1984 or 1985, and I wrote my own little terminal program with Xmodem built in to take advantage of it. Those were the days ...
(I still have the source code and of course it was called "Leech". Back then that was a generic term for somebody who downloaded far more than they uploaded, so it was a naturally good name.)
#retrocomputing

2025-02-18 21:48:33 UTC

Everybody needs a paper hex calculator. Make yours today!
http://www.brutman.com/Programmatics_Paper_Hex_Calculator.pdf
(Use a color laser printer, and feed it heavier paper for better results.)
#retrocomputing
https://mastodon.sdf.org/system/media_attachments/files/114/027/089/520/460/192/original/f31813b2b2fa803d.jpeg

2024-10-21 00:20:27 UTC

Good news everyone! A new mTCP for DOS is available!
http://www.brutman.com/mTCP/mTCP.html
Besides a few bug fixes this version lets you use the mTCP programs at the same time NetDrive is active. If you know how DOS packet drivers work, that is no small trick.
It might be slow; a PCjr is serving most of the web site to test both the web server and NetDrive. There is no hard drive on the machine; everything after the initial boot is running off of remote attached storage. In DOS!
#retrocomputing #mtcp