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History of the IBM PC, part two: The DOS empire strikes (arstechnica.com)
122 points by Tomte on July 31, 2017 | hide | past | favorite | 44 comments


> Paterson freely admits that he pulled out his CP/M reference manual and duplicated each of its API calls one by one. On the other other hand, and while it may not have reflected much originality or creative thinking, what he did was pretty clearly legal even by the standards of today.

And CP/M itself's command line interface closely matched that of DEC's earlier minicomputer operating system.


Ancient history few people know. AutoCAD started life as a CP/M application. When you bought ACAD you had to buy an 8087 math co-processor card as well as a 512K RAM drive card.

I ran ACAD for many years on such a system using a DEC VT-100 terminal, an early magnetic tablet with a wired puck having a coil for pickup and a large CRT-based graphics monitor. Memory restrictions were such that you had to do things like unload modules from memory before plotting and write clever code in Lisp to use less memory while drafting. Cool stuff.


That's what I thought as I worked on RT11 on PDP 11's when I saw a CP/M system I was struck by the similarity


Related: I've been impressed by the quality of PCem recently:

https://pcem-emulator.co.uk/

(Windows, Linux. Runs well on Mac via Wine.)

It emulates lots of specific pieces of historic PC hardware. Not cycle-accurate, but it's good enough to get roughly the correct speed for the CPU, graphics card you pick, etc.


There's also PCE (I hate these names, honestly): http://www.hampa.ch/pce/pce-ibmpc.html

It even offers a download with Microsoft Xenix 8086, and even one with PC/IX, which is actually the Unix you could get from IBM itself.

Now, if anyone can provide a disk image with UCSD Pascal (one of the operating systems originally available for the IBM PC), that'd be super cool.


As an example; it does a very neat impersonation of the Amstrad PC1512 (my first PC, back in 1989) including a faithful rendering of its unique 16 color CGA variation.

And unlike Dosbox, which doesn't try to run things at the proper speed, the right feeling is there...


I've always wondered why IBM chose Microsoft to create the OS - what someone told me just recently was that Bill's mother was [worked with the Chairman of] the IBM board which no doubt helped him get the contract.

https://en.wikipedia.org/wiki/Mary_Maxwell_Gates

edited: I've corrected this, she wasn't on the board but worked with Chairman.


According to the documentary "Triumph of the Nerds" and part 1 of the article. MS was a programming language shop. Basically they wanted to get IBM an OS so it would be successful and they'd sell more software.

https://arstechnica.co.uk/gadgets/2017/06/ibm-pc-history-par...

IBM didn't do their homework and went to microsoft for programming languages and and Operating System. Microsoft sent IBM to Gary Kildall's "Digital Research" company (they made CPM os). It was based in his house, he was away, his wife and lawyers wouldn't sign the NDA... They left empty handed, and Microsoft said they'd get them an OS.

[1]https://en.wikipedia.org/wiki/Gary_Kildall


>Before the IBM representatives would explain the purpose of their visit, they insisted that Dorothy sign a non-disclosure agreement. On the advice of DRI attorney Gerry Davis, Dorothy refused to sign the agreement without Gary's approval. Gary returned in the afternoon and tried to move the discussion with IBM forward, but accounts disagree on whether he signed the non-disclosure agreement, as well as if he ever met with the IBM representatives.[8]

No one knows what really happened.


>No one knows what really happened.

Probably more accurate to say that no single person knows the whole story. And those that know parts of the story can't necessarily be trusted to tell the truth, either from forgotten facts, or deliberately self serving commentary.

If you look at all of the stories from everyone, the facts that they all seem to agree on is that IBM went to Microsoft first, then went to Digital Research, and Microsoft came out a big winner. You could eventually buy an IBM PC with CPM, but at a much higher price. The reasoning behind those events are what's up for debate/speculation.


When I bought my first PC, there was IBM PC-DOS and IBM CPM/86 at the store. DOS was $40, CPM/86 was $180 (if I recall correctly). I (and everyone else) bought DOS for that reason.

Data I/O, the company I worked at, bought a few copies of CPM/86 and we tried it out. There were a few people who liked it, but most preferred DOS. Nobody could explain to me any reason to prefer CPM/86 - technical, practical, or price.

CPM/86 had a shot. IBM sold both. CPM/86 lost fair and square.


Did CP/M sell for $180 because DR priced it that way, or because IBM priced it that way?


I read once (sorry, don't remember where) that DR priced it that way because CP/M utterly dominated the 8 bit market and felt CPM/86 had the brand name and the technical superiority to charge a higher price.

The miscalculation is that IBM PC sales were mainly to first time users who had no history with CP/M, and (as I mentioned) the technical superiority of CPM/86 was not apparent.


The only "technical superiority" of CP/M that I can think of is having files associated with separate users, though I can't imagine anybody ever used this. The PIP command, copied from DEC OSes, was a lot more awkward than COPY in DOS.

But a significant problem with CP/M was that if you swapped a floppy disk in a drive the system wouldn't notice it and things could get really messed up, so you had to remember to always control-c after changing disks. DOS would check, which reduced performance but was much more user friendly.


DEC had COPY on their PDP-10 operating system at least as far back as 1975 when I started using it. DOS clearly had a lineage going back through CPM to DEC.

The CR-LF line endings also trace their way back to DEC.


> Data I/O, the company I worked at [...]

Hmmm...were you there when Data I/O was planning on acquiring Callan Data Systems? If so, what did you guys hear about the reason the acquisition did not go through?

I was at Callan at the time as a Unix kernel hacker, and we technical people never heard any solid information on why that acquisition did not happen.


Sorry, I was a bottom tier grunt and not privy to any management decisions.


If I recall from the documentary they had the ibm guy talking about going to Microsoft. I'll have to re watch :

Transcript snip http://www.pbs.org/nerds/part2.html:

Bill Gates: IBM didn't make it easy. You had to sign all these funny agreements that sort of said I...IBM could do whatever they wanted, whenever they wanted, and use your secrets however they - they felt. But so it took a little bit of faith.

Jack Sams was looking for a package from Microsoft containing both the BASIC computer language and an Operating System. But IBM hadn't done their homework.

Steve Ballmer: They thought we had an operating system. Because we had this Soft Card product that had CPM on it, they thought we could licence them CPM for this new personal computer they told us they wanted to do, and we said well, no, we're not in that business.

Jack Sams: When we discovered we didn't have - he didn't have the rights to do that and that it was not...he said but I think it's ready, I think that Gary's got it ready to go. So I said well, there's no time like the present, call up Gary.

Steve Ballmer: And so Bill right there with them in the room called Gary Kildall at Digital Research and said Gary, I'm sending some guys down. They're going to be on the phone. Treat them right, they're important guys.

The men from IBM came to this Victorian House in Pacific Grove California, headquarters of Digital Research, headed by Gary and Dorothy Kildall. Just imagine what its like having IBM come to visit - its like having the Queen drop by for tea, its like having the Pope come by looking for advice, its like a visit from God himself. And what did Gary and Dorothy do? They sent them away.

Jack Sams: Gary had some other plans and so he said well, Dorothy will see you. So we went down the three of us...

Gordon Eubanks: (Former Head of Language Division, Digital Research) IBM showed up with an IBM non-disclosure and Dorothy made what I...a decision which I think it's easy in retrospect to say was dumb.

Jack Sams: We popped out our letter that said please don't tell anybody we're here, and we don't want to hear anything confidential. And she read it and said and I can't sign this.

Gordon Eubanks: She did what her job was, she got the lawyer to look at the nondisclosure. The lawyer, Gerry Davis who's still in Monterey threw up on this non-disclosure. It was uncomfortable for IBM, they weren't used to waiting. And it was unfortunate situation - here you are in a tiny Victorian House, its overrun with people, chaotic.

Jack Sams: So we spent the whole day in Pacific Grove debating with them and with our attorneys and her attorneys and everybody else about whether or not she could even talk to us about talking to us, and we left.

This is the moment Digital Research dropped the ball. IBM, distinctly unimpressed with their reception, went back to Microsoft.

BOB: It seems to me that Digital Research really screwed up. STEVE BALLMER: I think so - I think that's spot on. They made a big mistake. We referred IBM to them and they failed to execute.

Bill Gates isn't the man to give a rival a second chance. He saw the opportunity of a lifetime.

Bill Gates: Digital research didn't seize that, and we knew it was essential, if somebody didn't do it, the project was going to fall apart.


Everything about this situation seems shady to me. It's really hard to take the story at face value. Especially given Gary's downward spiral afterward. There has to be _way_ more to this story than is widely known.


Just adding to the theme of "Bill Gates was a privileged, privileged man":

https://worldhistoryproject.org/1976/2/bill-gates-writes-ope...

> Microsoft's software development [for Altair BASIC] was done on a DEC PDP-10 mainframe computer system. Paul Allen had developed a program that could completely simulate a new microprocessor system. This allowed them to write and debug software before the new computer hardware was complete. They were charged by the hour and by the amount of resources used (storage, printing, etc.) The 6800 BASIC was complete before the Altair 680B was finished.[21] This was the $40,000 of computer time [mentioned in the "Open Letter To Hobbyists"].

[snip]

> The [PDP-10] computer system was funded by the Department of Defense through its Defense Advanced Research Projects Agency. The computer was delivered in the middle of the night in 1969 at the height of the Vietnam War protests. Harvard officials were not pleased that Gates and Allen (who was not a student) had used the PDP-10 to develop a commercial product. They determined that this military computer was not covered by any Harvard policy. The PDP-10 was controlled by Professor Thomas Cheatham who felt that students could use the machine for personal use. Harvard placed restrictions on the computer's use and Gates had to use a commercial time share computer until MITS provided access to a PDP-10 in Albuquerque.

Was it wrong, legally or morally, to use a DoD-funded computer to develop a commercial product? Dunno, but the point is, Gates had access to it because he went to Harvard, and the software he developed on it got him into the position where IBM noticed him and his company.


Isn't this how things always go? Technology often trickles down from military until someone makes it accessible for others. In this case it was Apple, Microsoft and to some degree IBM. Bill Gates seems to be a master at grabbing the opportunities given to him. I don't see a fault in that, as opposed to later business practices.


I love the clash between lawyers and a CS professor at Harvard that was simply happy some of it's students were programming and working on some personal projects.


Bill Gates was born in a privileged family but this is not enough to sustain super challenges Microsoft dealt for decades. He outwork almost everyone. I am not saying he didn't use unfair tactics, just saying that he was not only lucky.


There was nothing Gates or Jobs did that I and many others I personally knew couldn't have done at the same time. We had the knowledge to do it. We were just unaware of the possibilities, and lacked the nerve. Opportunity stared us in the face and we were blind.

None of us were wealthy or privileged.


Owning a computer, getting a college education, having a stable, supportive family are all privileges, and at least a couple of them require a good amount of money to spare. Not trying to play oppression olympics here, but I think we should try and recognize the privileges that many of us enjoy, and many others don't.


You could also argue that good health is a privilege. It is. But it isn't special. The late 70s were a time when computers were flooding the marketplace, and that could only happen if they were affordable for regular people.

I graduated in 1979 with a whole class of people who were quite capable of doing what Gates and Jobs did, and that's just from one university. But we didn't, and Gates/Jobs did. How do you explain that?

My father was career military. That isn't a recipe for wealth, and is an avenue available to millions of people.

You might be interested in the book "Masters of Doom" about John Carmack and John Romero. They had none of the privileges you assert, and yet vaulted to the top of the gaming industry.


>My father was career military. That isn't a recipe for wealth, and is an avenue available to millions of people.

I was actually going to ask this, but I didn't want to be presumptuous.

Your family, like mine, were probably recipients of GI Bill benefits. These benefits (like college grants and home loans) were systematically denied to black folks, disallowing them from participating in the post war economic boom.

There probably weren't a bunch of black students in your graduating class.

Bill Gates had a lot of guts and savvy on top of a great work ethic- and a lot of social advantages.


I guarantee you there's a billion dollar opportunity today right in front of my face that I do not see, but will find out about 5 years from now. It's in front of your face, too, and about every other HN reader.

Never in history has there been more opportunity than there is right now in software. Software is a completely unregulated free market, the barriers to entry are essentially zero, the market for a product is global, training materials are zero, and marketing costs can be zero.

All you need is some get up and go.


Cool, I don't disagree with you there. Just been arguing the specific point that you guys weren't privileged. Let's be real here.


I think you're confusing technical skills with executive functioning skills, or underestimating the value of executive functioning skills.

Having nerve isn't just a privilege. It's a skill you can learn. Same with decision making skills, etc.


success = luck + talent + effort


"The harder you work, the luckier you get." One of my favorite quotes.


"luck favors the prepared" -- Louis Pasteur

We still need to acknowledge that luck is part of the pattern.


Bill's mother also paid for the computer time at the high school Bill went to with his other friends who formed Microsoft with him. Since this was before the Microcomputer, time sharing on a minicomputer or mainframe was very expensive. So Bill and his friends had knowledge of programming a computer before anyone else did.

IBM claimed DRI charged too much for CP/M, and since Microsoft made BASIC IBM thought they could get a better deal on a DOS from Microsoft.

86-DOS became PC-DOS/MS-DOS and the DOS interrupts emulated the CP/M interrupts or API as it was later called. Back then, it was legal to reverse engineer stuff and make a copy of it using new source code. But the claim of Paterson and others was that they didn't pirate/steal CP/M they made an API in DOS that could run CP/M programs and then had a program that could convert a program to DOS from CP/M because the executable file format was different in DOS.

Microsoft did undercut CP/M in OS price, which was a big factor in getting paid by IBM and other OEMS for their DOS.

Microsoft Windows came out in 1985 and over the years it took more and more features from the Apple Macintosh. It did not have the source code of a Mac, but it was designed to use some of the look and feel from a Mac. Enough for trade dress lawsuits. Microsoft and Apple settled their differences out of court in the late 1990's.

CP/M was a good operating system, my father bought me and my siblings a Commodore 128 after the Commodore 64 died. By that time the Z80 coprocessor on the 128 ran CP/M80 for cheap, but it was too late, DOS had killed CP/M.


Based on that Wikipedia article, she was not on IBM's board, but that of a non-profit named United Way which also included IBM's chairman on its executive committee.


Thank goodness for Wikipedia as this story is like the 640Kb quote that was only ever said because people say so, not because they actually heard it.

I was of the opinion that it was the IBM board, not some non profit, I am sure I would have noticed the difference. Somewhere out there is a well written version of the story with this detail wrong.


> the 640Kb quote

I read somewhere[1] that the quote is technically accurate but taken out of context, in that it did not mean that 640K were enough for everyone forever. And at the time the IBM PC was introduced, 640K were plenty of RAM for a single user.

(I think it was "Expert C Programming" by Peter van der Linden.)


My impression is that the 640KB quote started as a huge simplification of the arguments Bill Gates made in an article in an early PC Magazine (might have been a rival magazine instead - it has been 35 years since I read it) defending IBM's decision to "waste" so much of the precious 1MB address space on I/O. And he was right: without this networking and betters graphics would have been much harder to do later on.


For anyone interested in the era of other “retro” computers and companies in the 1980s, Kim Justice’s documentaries on YouTube are pretty good.


Kim Justice is good but game oriented. For people interested in the machines of the era including more business oriented machines, check out Tezza's channel: https://www.youtube.com/user/tezzaNZ


I'm reading Andy Grove's book, "Only the Paranoid Survive" and he discusses the decline of IBM and rise of Intel.

Remains surprisingly relevant even though it was written over a decade ago, and an interesting view of PC history.


It's surreal reading the phrase, "History of the IBM PC".


Well with the intro of UEFI, the last remanins of the original IBM PC, the BIOS, have been relegated to an emulated mode.


The motherboard form factors are still closely related. ATX is an extended version of the IBM AT standard.




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