Multitasking MS-DOS 4.0, Goupil OEM

The recently unearthed copy of the near-mythical Multitasking (aka European) MS-DOS 4.0 clearly did not want to be alone. James Lariviere, a kind reader of this blog, provided a disk image of multitasking DOS 4 which was released in 1986 by the French company SMT Goupil.

Multitasking DOS 4, Goupil OEM

Microsoft’s contract with Goupil was the main reason why multitasking DOS 4 was completed at all. Goupil was the most important and perhaps even only OEM shipping multitasking DOS 4 (British ICL was the primary customer of the updated multitasking DOS 4.1 in 1987).

The machine that multitasking DOS 4 ran on was the Goupil G4, and a brief look at the machine’s specs reveals why Goupil was interested in multitasking DOS 4: The G4 was equipped with an 8 MHz Intel 80186 processor. Continue reading

Posted in DOS, Microsoft, OS/2 | 27 Comments

The ISA OSC Mystery

About twenty years ago I ended up with a spare ISA graphics card from an upgraded computer. It was a SVGA card based on the Cirrus Logic CL-GD5422 chip, equipped with 1 MB video memory.

Cirrus Logic CL-GD5422

This was a very cheap graphics card sold as part of a low-end PC in 1993 by ESCOM, a large European (originally German) PC retailer. It was a basic but hassle-free card, it was no speed demon but did its job well.

Now fast forward nearly twenty years. In the quest for the Ultimate Museum PC, I tried this old VGA card in a 440BX board (Abit BP6). It didn’t work. At all. There was no video signal whatsoever. I assumed that the card was most likely dead, because other (even older) ISA VGA cards did work in the same 440BX system. But I didn’t throw the card out… just in case. Continue reading

Posted in Cirrus Logic, Graphics, PC hardware | 8 Comments

386 ZIF Socket?

I have a problem:

386 Chips

Anyone familiar with 386 LIF (Low Insertion Force) sockets knows that the trouble isn’t installing the processors—that indeed doesn’t require much force and is easy to do. The real problem is getting the processor out without bending the pins and/or damaging the ceramic package.

This got me wondering… surely it would be possible to build a ZIF (Zero Insertion Force) socket for the 132-pin PGA used on 386s, just like the larger sockets used for 486 processors? Is anyone familiar with such a thing? Continue reading

Posted in 386 | 17 Comments

MS-DOS 1.1, 2.0 Source Code Released

In cooperation with the excellent Computer History Museum in Mountain View, Microsoft released the source code to MS-DOS 1.1, MS-DOS 2.0, and Microsoft Word for Windows 1.1a.

Here’s hoping that this is a sign of things to come and Microsoft will also release the source code to historic versions of Windows 1.x, 2.x and 3.x, further versions of MS-DOS—and maybe even OS/2 1.0!

The poor CHM server is currently suffering from a severe overload so actually looking at the goodies will have to wait… Continue reading

Posted in DOS, Microsoft, PC history | 48 Comments

IBM OS/2 1.0 in a VM

As previously mentioned, IBM’s OS/2 1.0 and 1.1 is extra unfriendly to modern hypervisors. To recap, there is a curious difference between IBM’s and Microsoft’s kernels in OS/2 1.0/1.1 with regard to mode switching.

For reasons that aren’t very clear, IBM’s kernels implement only 286 style mode switching: In order to get from protected back to real mode, the processor is reset and the BIOS told where to resume execution. On the other hand, Microsoft’s kernels have had (faster) 386-specific code ever since the first OS/2 SDK beta from April 1987.

To make matters more interesting, the OS/2 kernel is also famous for using the undocumented LOADALL instruction when running on a 286. Yet IBM’s OS/2 did run on 386 AT clones of the era. How is that possible? Continue reading

Posted in IBM, Microsoft, OS/2, VirtualBox, Virtualization | 6 Comments

What’s in a Name?

The following four processors are much more similar than one might think:

486 Medley

486 aficionados will recognize the processors made by IBM, ST Microelectronics, and Texas Instruments to be essentially one and the same model—Cyrix 486DX. Continue reading

Posted in 486, Cyrix | 5 Comments

Surfing Modern Web With Ancient Browsers

(note this is a guest post by Tenox)

I spend a fair amount of time working with legacy operating systems. Apart from being obsolete themselves they suffer from a common problem – the web browsers are simply unusable on a present day Internet. You start by getting JavaScript error on and it only gets worse once you go further. Try going to with IE 1.5 or with the last version of Voyager. This just doesn’t work. With rapid progression of web standards, the situation will only be getting worse in time. Something had to be done to ease the situation.

Quite a while ago I’ve came across Opera rendering proxy for mobile browsers. This got me thinking. If you could render a web page on a proxy server to a simplified HTML, say 3.x. This would make a lot of web browsers happy. For some unrelated purposes I have been using webkit2png which allows to create a whole web page snapshot in a single png image. Wait… what if such image had an image map of clickable regions pointing to the original links? Maybe… Continue reading

Posted in Networking | 3 Comments

Kids These Days, Continued

As the OS/2 museum pointed out, many kids these days don’t really know how to properly use floppies. Fortunately, not all is lost and at least some youngsters know exactly what to do with a 3½” diskette.

First, firmly hold the floppy…

How to Use a Floppy (1)

Continue reading

Posted in Floppies | 5 Comments

Soyo SY-4SAW2 Notes

Following is a list of notes describing several less-than-obvious features and characteristics of the Soyo SY-4SAW2 486 VIP motherboard. This is a latter-day 486 board based on the SiS 496/497 chipset, notable for PS/2 mouse support and the ability to use just about any CPU compatible with Socket 3.

Most of these characteristics and limitations are a direct consequence of the use of the SiS 85C496/497 chipset and the way said chipset is configured in the 4SAW2 board. Continue reading

Posted in 486, PC hardware | 2 Comments

Untested Error Paths

About a week ago I revived an old Sony VAIO laptop (model PCG-R505TS) that hadn’t been used for a few years. It had lost CMOS contents so I had to re-enter the date and adjust a few BIOS settings.

The laptop had XP SP1 installed, which I successfully updated to SP3. Too lazy to use the built-in wired Ethernet, I plugged in a Belkin wireless PC Card instead. Windows Update successfully installed the usual bazillion of updates and the laptop was running stable, yet I was experiencing inexplicable errors and odd behavior.

Some web sites reported certificate errors, which I (erroneously, it turned out) ascribed to out of date root certificates on the system. Updated root certificates are available on Windows Update, but that’s where another strange problem hit: For whatever reason, the root certificates are an optional update and as such, require Windows to be validated (the infamous WGA). Windows Update offered to validate my copy of Windows, but the validation process eventually landed on an empty web page with no error message whatsoever. The validation did not really fail (declaring my setup a pirate copy), it just did nothing. What was I doing that was so unusual to trigger some untested error path?

Continue reading

Posted in PC hardware, Windows | 2 Comments