Microsoft Updates MS-DOS GitHub Repo To 4.0

April 26, 2024 by Tom Nardi 30 Comments

We’re not 100% sure which phase of Microsoft’s “Embrace, Extend, and Extinguish” gameplan this represents, but just yesterday the Redmond software giant decided to grace us with the source code for MS-DOS v4.0.

To be clear, the GitHub repository itself has been around for several years, and previously contained the source and binaries for MS-DOS v1.25 and v2.0 under the MIT license. This latest update adds the source code for v4.0 (no binaries this time), which originally hit the market back in 1988. We can’t help but notice that DOS v3.0 didn’t get invited to the party — perhaps it was decided that it wasn’t historically significant enough to include.

That said, readers with sufficiently gray beards may recall that DOS 4.0 wasn’t particularly well received back in the day. It was the sort of thing where you either stuck with something in the 3.x line if you had older hardware, or waited it out and jumped to the greatly improved v5 when it was released. Modern equivalents would probably be the response to Windows Vista, Windows 8, and maybe even Windows 11. Hey, at least Microsoft keeps some things consistent.

It’s interesting that they would preserve what’s arguably the least popular version of MS-DOS in this way, but then again there’s something to be said for having a historical record on what not to do for future generations. If you’re waiting to take a look at what was under the hood in the final MS-DOS 6.22 release, sit tight. At this rate we should be seeing it sometime in the 2030s.

640k Was Never Enough For Anyone: How DOS Broke Free

January 21, 2024 by Jenny List 37 Comments

On modern desktop and laptop computers, there is rarely a need to think about memory. We all have many gigabytes of the stuff, and it’s just there. Our operating system does the heavy lifting of working out what goes where and what needs to be paged to disk, and we just get on with reading Hackaday, that noblest of computing pursuits. This was not always the case though, and for early PCs in particular the limitations of the 8086 processor gave the need for some significant gymnastics in search of an extra few kilobytes. [Julio Merion] has an interesting run-down of the DOS memory map, and how memory expansion happened on computers physically unable to see much of it.

The 8086 has a 20-bit address bus, giving it access to a maximum of 1 megabyte. When IBM made the PC they needed space for the BIOS, the display, and the various accessory ROMs intended to come with expansion cards. Thus they allocated a maximum 640k of the map for RAM, and many early machines shipped with much less than that. The quote from Bill Gates about 640k being enough for anyone is probably apocryphal, but it was pretty clear as the 1980s wore on that more would be needed. The post goes into how memory expansion worked, with a 64k page mapped to switchable RAM on a card, and touches on how DOS managed extended memory above 1 Mb on the later processors that supported it. We dimly remember there also being a device driver that would map the unused graphics memory as EMS when the graphics card was running in text mode, but such horrors are best left behind.

Of course, some of the tricks to boost RAM were nothing but snake oil.

8086 header: Thomas Nguyen, CC BY-SA 4.0

A Web Server, The Sixteen Bit Way

December 25, 2023 by Jenny List 13 Comments

If you were to talk about sixteen bit computing in retrocomputing circles, misty-eyed reminiscences of the ST or Amiga would emerge. Both fine platforms, but oddly the elephant in the 16-bit room has become a victim of its own success. DOS, the granddaddy of all PC operating systems, seems oddly overshadowed by its 68000-based competitors in a way it certainly wasn’t back in the day. Perhaps it’s the often-atrocious graphics when cards designed for business graphics were pressed into gaming service, but it’s easy to forget that DOS PCs were the powerhouses of their day. They still pack a punch even in 2023, as [Lunduke] is here to show us by running a DOS web server. Take that, nginx! Continue reading “A Web Server, The Sixteen Bit Way” →

Myth Tested: DOS Can’t Multitask

August 9, 2023 by Jenny List 77 Comments

It’s a piece of common knowledge, that MS-DOS wasn’t capable of multitasking. For that, the Microsoft-based PC user would have to wait for the 80386, and usable versions of Windows. But like so many such pieces of received Opinion, this one is full of holes. As [Lunduke] investigates, there were several ways to multitask DOS, and they didn’t all depend on third-party software.

A quick look at DESQview and Concurrent DOS was expected from this article, but of more surprise is that IBM had a multitasking DOS called TopView, or even that Microsoft themselves released the fully multitasking MS-DOS 4.0. We remember DOS 4 as being less than sparkling, but reading the article it’s obvious that we’re thinking of the single-tasking version 4.01.

From 2023 it seems obvious that multitasking is a fundamental requirement of PC use, but surprisingly back in the 1980s a PC was much more a single-application device. On one hand it’s surprising given the number of multitasking DOS products on the market that none of them became mainstream, but perhaps the best evidence of the PC market simply not being ready for it comes in the fact that they didn’t.

If you fancy experimenting with DOS multitasking, at least machines on which to do it can still be found.

MS-DOS Meets The Fediverse

August 9, 2023 by Bryan Cockfield 30 Comments

By now, most Windows users are set up with decently functional machines running Windows 10 or 11. Of course there are a few legacy machines still lagging behind on Windows 7 or 8 and plenty of computers in industrial settings running ancient proprietary software on Windows XP. But only the most hardcore of IBM PC users are still running DOS, and if you have eschewed things like Unix for this command-line operating system this long you might want to try using it to get online in the Fediverse with Mastodon.

The first step is getting DOS 6.22, the most recent version released in 1994, set up with all the drivers and software needed to access the Internet. At the time of its release there were many networking options so the operating system didn’t include these tools by default. [Stephen] first sets up an emulated NE2000-compatible networking card and then installs the entire TCP/IP stack and then gets his virtual machine set up with an IP address.

With a working Internet connection set up, the next step on the path of exploring federated social media is to install DOStodon (although we might have favored the name “MastoDOS”) which is a Mastodon client specifically built for MS-DOS by [SuperIlu]. There are pre-compiled packages available on its GitHub page for easy installation in DOS but the source code is available there as well. And, if this is your first time hearing about the Fediverse, it is mostly an alternative to centralized social media like Facebook and Reddit but the decentralization isn’t without its downsides.

That Handheld 386SX Gets A Teardown

June 6, 2023 by Jenny List 18 Comments

A few weeks ago our community was abuzz with the news of a couple of new portable computers available through AliExpress. Their special feature was that they are brand new 2023-produced retrocomputers, one with an 8088, and the other with a 386SX. Curious to know more? [Yeo Kheng Meng] has one of the 386 machines, and he’s taken it apart for our viewing pleasure.

What he found is a well-designed machine that does exactly what it claims, and which runs Windows 95 from a CF card. It’s slow because it’s an embedded version of the 386 variant with a 16-bit bus originally brought to market as a chip that could work with 16-bit 286-era chipsets. But the designer has done a good job of melding old and new parts to extract the most from this vintage chip, and has included some decidedly modern features unheard of in the 386 era such as a CH375B USB mass storage interface.

If we had this device we’d ditch ’95 and run DOS for speed with Windows 3.1 where needed. Back in the day with eight megabytes of RAM it would have been considered a powerhouse before users had even considered its form factor, so there’s an interesting exercise for someone to get a vintage Linux build running on it.

One way to look at it is as a novelty machine with a rather high price tag, but he makes the point that considering the hardware design work that’s gone into it, the 200+ dollar price isn’t so bad. With luck we’ll get to experience one hands-on in due course, and can make up our own minds. Our original coverage is here.

New DOS PCs, In 2023?

May 15, 2023 by Jenny List 85 Comments

It’s not likely that we’ll talk about a new PC here at Hackaday because where’s the news in yet another commodity computer? But today along comes not one but two new PCs courtesy of the ever bounteous hall of wonders at AliExpress, that are unusual enough to take a look at. If you have around $250 to spare, you can have a brand new, made in 2023, 80386sx plamtop PC capable of running Windows 95, or an 8088 laptop for DOS. Just what on earth is going on?

Continue reading “New DOS PCs, In 2023?” →