My retro activity from yesterday ... coding a DOS device driver.

I've never written one. Even with a reasonably good book there is still a lot of research and experimentation that I have to do to make progress. Here are some of the challenges:

• I'm using Open Watcom's assembler, which seems to be MASM compatible but I have no documentation for it. If it gives me trouble I'll install MASM.
• I can do some light x86 assembly language, but the device driver is on another level. It takes a lot of discipline to know what registers are safe to use and which ones need to be restored.
• I'm testing in a virtual machine. Rebooting after a crash is easy but it is irritating to move code onto it. (I have a batch files that FTPs the device driver.)
• I'm using IOCTL to control the device driver .. IOCTL doesn't seem to be very well documented.
• I want it to run under DOS 2 and up, so I need to be careful about what features I enable/use.

On the plus side, it's fun. And I have a much better understanding of how device drivers work now even though I'm just a week into this.

mbbrutman wrote on 2023-09-05, 22:47:

My retro activity from yesterday ... coding a DOS device driver.

Can you provide any references you're using for books and documentation? I would love to see any of this code available on GitHub, if you wouldn't mind sharing.

Kahenraz wrote on 2023-09-05, 22:52:

mbbrutman wrote on 2023-09-05, 22:47:

My retro activity from yesterday ... coding a DOS device driver.

Can you provide any references you're using for books and documentation? I would love to see any of this code available on GitHub, if you wouldn't mind sharing.

If you're looking for books for coding DOS drivers, there are a couple available at the Open Library:

https://openlibrary.org/search?q=Ms-dos+drive … s_fulltext=true

It's a pretty good resource for old computer books. Best of all, it's free.

I can't vouch for these specific books, but it wouldn't hurt to check them out.

Kahenraz wrote on 2023-09-05, 22:42:

RetroGamer4Ever wrote on 2023-09-05, 20:06:

Yes, it is an official SF and I forgot that it existed, until I remembered that I downloaded it. It was only distributed on the Sound Blaster software discs and not in the software package install web downloads from Creative. In addition to a pile of GM files, I tested it with XG and GS files and it sounded pretty good with those. They also made an MT-32 SF and a GS one.

Can you share the file names so we know what to look for? I wasn't aware of these larger soundfont files either.

If I'm recalling correctly, the AWE64 had an MT-32 and GS SF. I simply remember they had those in their file names. This 28MB GM SF is apparently from the X-Fi install CDs and can be found elsewhere.

https://gmsynths.blogspot.com/2016/02/list-of … soundfonts.html

Kahenraz wrote on 2023-09-05, 22:45:

It might have gotten under the solder mask. Hopefully you've neutralized it, otherwise you'll have to dig it out, if it has perm […]
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Nexxen wrote on 2023-09-05, 19:52:

Cleaned a 286 board.
Some green corrosion won't come off and I don't know how to remove it without a few more vinegar runs.
Varta is the best to teach you trace rebuild 😀

It might have gotten under the solder mask. Hopefully you've neutralized it, otherwise you'll have to dig it out, if it has permeated through the first layer of fiberglass substrate (don't do this right now, just watch it for a while if it's not accessible).

See here for photos where I had to dig out some PCB eating corrosion on my SC-55 synthesizer:

PCB destroying adhesive found in my Roland Sound Canvas SC-55mkII (inspect your synthesizer!)

Yep, neutralized but I think it was already over as I saw no fizzing after pouring it on. Other times I did it, it just went bonkers with bubbles, a true show. I suspect it happened 25-30 yrs ago or maybe the battery leaked a little but not all of its content.

I'll create a new thread for this repair. It's gonna take less than this winter (I'm too intrigued to see if I can make it to the end semi on my own) to repair it.
Fortunately it didn't go as deep as yours, worst I'll have just to rebuild traces (tedious but can be done).

It's nice to see a repair, at least you made my eyes happy 😀

edit: Before and after pictures.

Kahenraz wrote on 2023-09-05, 22:52:

mbbrutman wrote on 2023-09-05, 22:47:

My retro activity from yesterday ... coding a DOS device driver.

Can you provide any references you're using for books and documentation? I would love to see any of this code available on GitHub, if you wouldn't mind sharing.

I'm using Writing MS-Dos Device Drivers by Robert S. Lai at the moment.

If you are looking for samples, there are plenty of DOS device drivers on GitHub right now - no need to wait.

mbbrutman wrote on 2023-09-06, 00:06:

I'm using Writing MS-Dos Device Drivers by Robert S. Lai at the moment.

I'm not familiar with assembly, but I placed and order for Writing DOS Device Drivers in C by Philip M. Adams. I'm looking forward to it.

What kind of device driver are you writing?

I'm looking to provide a virtual hard drive over the network. There are a few of these floating around, so it's not exactly new ground. Here is what I want mine to look like:

• Based on UDP so that you can run the server on Linux or Windows without special packages or permissions.
• UDP also makes it routable across the internet; you could remotely mount a drive if you wanted to.
• One machine connects to the virtual drive at a time when in read-write mode. (Allowing more than one machine is a lot of work and not worth it; SAMBA already exists.)
• Read only virtual hard drives can have multiple machines connected at the same time.
• Works with a packet driver. Will also allow mTCP or other programs to work at the same time on the same network card. (This is the big challenge.)
• Standard mTCP goodness - small size, fast performance.
• Supported on DOS 2.0 or better.

Kahenraz wrote on 2023-09-05, 22:42:

RetroGamer4Ever wrote on 2023-09-05, 20:06:

Yes, it is an official SF and I forgot that it existed, until I remembered that I downloaded it. It was only distributed on the Sound Blaster software discs and not in the software package install web downloads from Creative. In addition to a pile of GM files, I tested it with XG and GS files and it sounded pretty good with those. They also made an MT-32 SF and a GS one.

Can you share the file names so we know what to look for? I wasn't aware of these larger soundfont files either.

I will share the Creative 1/2/4/8/28MB SF2s on google drive and post here later tonight.

DerBaum wrote on 2023-09-05, 10:21:

Daniël Oosterhuis wrote on 2023-09-05, 07:21:

There's a 3D model of such a bezel for printing on Thingiverse.

Awesome! Thanks a lot... I had not used the right keywords for my search.. Thanks again.

No worries, I had to look around for a while before finding it as well, for an XT PSU I have with a similarly broken bezel.

Daniël Oosterhuis wrote on 2023-09-06, 09:38:

No worries, I had to look around for a while before finding it as well, for an XT PSU I have with a similarly broken bezel.

Because my 3d printer is broken, i have ordered 2 bezels online yesterday. When they arrive i will post some pictures.

Sometimes i have problems to make decisions.
I didnt know Intel has the same problems...

Makes me feel a little bit better 😏

mbbrutman wrote on 2023-09-06, 02:48:

I'm looking to provide a virtual hard drive over the network. There are a few of these floating around, so it's not exactly new […]
Show full quote

I'm looking to provide a virtual hard drive over the network. There are a few of these floating around, so it's not exactly new ground. Here is what I want mine to look like:

• Based on UDP so that you can run the server on Linux or Windows without special packages or permissions.
• UDP also makes it routable across the internet; you could remotely mount a drive if you wanted to.
• One machine connects to the virtual drive at a time when in read-write mode. (Allowing more than one machine is a lot of work and not worth it; SAMBA already exists.)
• Read only virtual hard drives can have multiple machines connected at the same time.
• Works with a packet driver. Will also allow mTCP or other programs to work at the same time on the same network card. (This is the big challenge.)
• Standard mTCP goodness - small size, fast performance.
• Supported on DOS 2.0 or better.

iSCSI is IP but TCP. https://en.wikipedia.org/wiki/ATA_over_Ethernet is not IP based but very simple and pretty cool. You could adapt AoE to UDP while keeping overall protocol compatible.

DerBaum wrote on 2023-09-06, 15:38:

Sometimes i have problems to make decisions. I didnt know Intel has the same problems... 2023-08-30 13.38.20.jpg Makes me feel a […]
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Sometimes i have problems to make decisions.
I didnt know Intel has the same problems...
2023-08-30 13.38.20.jpg
Makes me feel a little bit better 😏

There are a few specs they did that with 😀

I was setting up a 1995 retro rig with dual sound cards. But I just could not get my non PNP sb16 to recognize its mpu port. I almost sure I had it working the other week... Tried for maybe two hours... Blamed the unisound drivers.. Then as a last try, I reseated the jumpers on the card and voila, it found mpu at adress 330.

Yay victory!

Joakim wrote on 2023-09-06, 20:54:

I was setting up a 1995 retro rig with dual sound cards. But I just could not get my non PNP sb16 to recognize its mpu port. I almost sure I had it working the other week... Tried for maybe two hours... Blamed the unisound drivers.. Then as a last try, I reseated the jumpers on the card and voila, it found mpu at adress 330.

Yay victory!

Dodgy jumpers are evil. So easy to get confused when a jumper isn't actually making contact.

Re-capped another motherboard, this time a Lucky Star K7VAT.

Testing the caps I removed, turns out that every single one was bad. Usually some of the caps are still good, but not this time...

Shponglefan wrote on 2023-09-07, 02:09:

Re-capped another motherboard, this time a Lucky Star K7VAT.

Testing the caps I removed, turns out that every single one was bad. Usually some of the caps are still good, but not this time...

It is also quite interesting how much there can be differences between caps from the same manufacturers, at least when we are talking about the dodgy ones.

I recently recapped most VRM caps of EpoX 8rga+. Most of them were GSC RE and LE series and handful of Sanyos which I at this point decided to leave on the board.

Most GSC REs were already bloated more or less and those naturally also tested bad. I was pretty certain that LE series are bad also, although they were visibly OK. But when I removed and messured those, every single one of them was 100% in the spec! Of course I replaced them with new caps, but it still was somewhat surprising finding them in such condition, especially when GSC low ESR caps are known to be of poor quality.

Edit: I also recently recapped the secondaries on two Enermax 5V heavy PSUs. Both were full of CEC PCE TUR and TUL caps, which aren’t considered a top quality brand, but not bottom of the barrell either. Every cap looked good and I measured quite many of them and all were in spec. Sometimes the capacitor rot just isn’t an issue.

DerBaum wrote on 2023-09-06, 15:38:

Because my 3d printer is broken, i have ordered 2 bezels online yesterday. When they arrive i will post some pictures. […]
Show full quote

Daniël Oosterhuis wrote on 2023-09-06, 09:38:

No worries, I had to look around for a while before finding it as well, for an XT PSU I have with a similarly broken bezel.

Because my 3d printer is broken, i have ordered 2 bezels online yesterday. When they arrive i will post some pictures.

---

Sometimes i have problems to make decisions.
I didnt know Intel has the same problems...
2023-08-30 13.38.20.jpg
Makes me feel a little bit better 😏

Clear thing: top secret dual core prototype 😉

But there're more:
https://www.cpu-world.com/sspec/SL/SL8BM.html
First picture at bottom of site.

I have too many small form factor systems that I haven't finished setting up. I have a bad habit of grabbing old laptops and thin clients when I see them going for cheap and then leaving them on the shelf for awhile. My current focus is to finish setting them up, so I can just grab one of the shelf and fire it up whenever I want. Today, I worked on my Wyse CX0 thin client. I wanted to try that Henk guy's Ultimate MS-Dos 7.1. Being a thin client without a floppy or CD drive made it a lot harder. I had to use a virtual machine to install it to a compact flash drive on my Windows 10 machine. Next step will be to get the sound working and it should be about done.

I "fixed" my ThinkPad A31p and I'm very happy about it. Had the problem that it was drawing too much power und tripping the power supply (which was running very hot) after a few minutes.

So I got a thermal camera to debug this, disassembled the whole thing, found nothing, reassembled it...and the problem went away.

What the...

The only explanation I have for this is that I might have accidentally produced a short when I put it together the last time and did it properly this time.