MS-DOS was *not* an illegal clone of CP/M

[liam_on_linux]

"MS-DOS" is the MS version of what IBM sold as PC DOS. Microsoft produced that on very short notice by licensing (note, not buying) 86-DOS from Seattle Computer Products. That was originally called QDOS, for Quick’n’Dirty OS.

Tim Paterson wrote QDOS based on studying the docs for CP/M and CP/M-86. It was API compatible, but used a different disk filesystem: Paterson used the FAT format of MS’ standalone disk BASIC.

It was wholly-new code, but written to be closely compatible with DR’s published info about CP/M.

That is not even reverse-engineering. Indeed CP/M-86 was released late and it didn’t even exist to be reverse-engineered yet, AFAIK. QDOS was written for and sold with SCP’s 8086 cards in 1979; CP/M-86 did not ship until 1981.

Writing compatible code to a published API is what APIs are for. That’s why the info is published.

QDOS wasn’t a clone of CP/M-86; in fact, it is older than and predated CP/M-86.

It was a compatible OS written to info DR published. That is entirely legal. DR published the APIs intending this for app writers, not for people writing OSes compatible with DR OSes, but it’s not breaking any rules.

In fact in the late 1970s there were lots of CP/M clones out there, such as CPN and Cromemco CDOS and many others. Later MSX-DOS was a much-enhanced CP/M clone.

The difference is, most other companies cloned CP/M on 8080 or Z80. SCP did it on 8088/8086.

But while yes, it’s arguably something like a clone (for different hardware, with a different file system), it was just one of many and didn’t use anything illegal or violate any licenses.

The key thing is that QDOS ran on then-modern hardware with a future. Most of the others ran on what was rapidly becoming obsolete hardware. SCP QDOS became 86-DOS became PC DOS and MS-DOS, and sold in the tens of millions of copies, and made MS huge amounts of money.

DR and IBM made big bad mistakes and it cost them dominance of their industries and lots of money. MS was smart and got lucky and got very very rich.

Later on, MS abused that power repeatedly, stole code, copied ideas, unfairly pushed rivals out of business, and generally became a bully and a criminal. MS effectively killed Be, Netscape, and Central Point Software; it crippled Aldus and STAC; and many more.

But DR survived and briefly it staged a successful comeback, before being bought by Novell.

I entirely understand how angry Dr Gary Kildall was. It was justified. But he did make mistakes. Sadly some of them are only clear in hindsight. DR should have rushed to make CP/M-86 quickly for IBM, and reserved the rights to sell it to others, as Microsoft did. DR should have sold single-user single-tasking CP/M-86 cheaply, building the market, and made Concurrent CP/M the premium product. It should have sold GEM cheaply to get wide adoption. It should have made standalone single-user multitasking CP/M a desirable power-user OS, rather than aiming at the multiuser market, which was on the way out as PCs got cheaper and cheaper.

But as little as I personally like MS, in how it cornered the market and became rich, it did it by being clever, and fast, and outmaneuvering bigger, slower rivals, and there’s nothing wrong with that.

Comments

[liam_on_linux]

That requires IBM to have been willing to make the PS/2 models 50 and 60 significantly more expensive, by giving them 386 processors (rather than 286) and more RAM (4MB rather than 2MB)

The ones I worked on -- quite a few of 'em -- came with only 1MB.

I have idly speculated on this before. The 50 & 60 sold well: they were relatively affordable, for PS/2s, but they were proper ones, not like the Model 30 & 30-286, which weren't real PS/2s at all, being ISA-based.

None of the customers I dealt with wanted OS/2 at all. In the longer run, IBM could have given free planar upgrades to every PS/2 50 & 60 owner who bought OS/2 & a RAM upgrade. It would have made more of a profit from the more successful OS.

(There are some wrinkles to work out here: how to limit it so that freeloading chancers don't order OS/2 just so as to get a free upgrade. But IBM was smart. They could have done it.)

IBM crippled the product, and in the end destroyed its own PC business and handed the OS market to MS, just to honour a pledge its customers didn't care about.

In the IT press at the time, there was speculation as to which partner wanted it to run on the 386, but in hindsight, the answer is clear.

Because MS was already working on 386 versions of the OS. Decades later, they leaked.

The original MS-DOS 4, the multitasking version, released only in Europe: https://www.os2museum.com/wp/multitasking-ms-dos-4-0-lives/

A Goupil version: https://www.os2museum.com/wp/multitasking-ms-dos-4-0-goupil-oem/

A prototype, "Sizzle", with 386 code: https://www.os2museum.com/wp/before-os2-was-os2/

Which became the 386-specific "Football": https://www.os2museum.com/wp/playing-football/

It's out there.

MS was working on adding 386 enhancements and support for 386 V86 multitasking to DOS, using prototype Compaq kit.

In the light of that, I think it's easy to deduce which of the 2 partners wanted the new OS to run on the 286.

To be fair it is only in hindsight that it is so clear which was the right direction. At the time, it wasn't so clear. The 286 was called a superchip when it came out, as I reference here: https://www.theregister.com/2022/08/04/the_many_derivatives_of_cpm/

Direct link to InfoWorld: https://books.google.cz/books?id=ZjAEAAAAMBAJ&lpg=PA4&pg=PA4#v=onepage&q&f=false

(Reversing order for clarity)

That requires Jack Tramiel to have died or become incapable of running Atari in about 1986. He was very focussed on consumer systems, and wasn't very interested in flexibility.

Well that might be so, but I had a specific machine in mind, and it was the 1990 Atari TT: https://en.wikipedia.org/wiki/Atari_TT030

The OS that I was thinking of was MiNT: https://en.wikipedia.org/wiki/MiNT

Which later shipped with the TT replacement, the 1992 Falcon: https://en.wikipedia.org/wiki/Atari_Falcon

... which I submit shows that Atari had some awareness it needed a better OS.

I worked for Perihelion Hardware while they were trying to turn the Atari Transputer Workstation into something saleable, as opposed to demonstrable, and Jack did not seem interested.

If I knew that, I had forgotten! Did you see my article about Parhelion HeliOS?

https://www.theregister.com/2021/12/06/heliosng/