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The History of Computing

199 EpisodesProduced by Charles EdgeWebsite

Computers touch all most every aspect of our lives today. We take the way they work for granted and the unsung heroes who built the technology, protocols, philosophies, and circuit boards, patched them all together - and sometimes willed amazingness out of nothing. Not in this podcast. Welcome to th… read more

9:40

CP/M

Welcome to the History of Computing Podcast, where we explore the history of information technology. Because understanding the past prepares us to innovate (and sometimes cope with) the future! Today we’re going to look at an often forgotten period in the history of computers. The world before DOS. 

I’ve been putting off telling the story of CP/M. But it’s time. Picture this: It’s 1974. It’s the end of the Watergate scandal. The oil crisis. The energy crisis. Stephen King’s first book Carrie is released. The Dolphins demolish my Minnesota Vikings 24-7 in the Super Bowl. Patty Hearst is kidnapped. The Oakland As win the World Series. Muhammad Ali pops George Forman in the grill to win the Heavyweight title. Charles de Gaulle opens in Paris. The Terracotta Army is discovered in China. And in one of the most telling shifts that we were moving from the 60s into the mid-70s, the Volkswagen Golf replaces the Beetle. I mean, the Hippies shifted to Paul Anka, Paper Lace, and John Denver. The world was settling down.

And the world was getting ready for something to happen. A lot of people might not have known it yet, but the Intel 8080 series of chips was about to change the world. Gary Kildall could see it. He’d bought the first commercial microprocessor, the Intel 4004 when it came out in 1971. He’d been enamored and consulted with Intel. He finished his doctorate in computer science and went tot he Naval Postgraduate School in Monterrey to teach and developed Kildall’s Method, to optimize compilers. But then he met the 8080 chip. 

The Intel Intellec-8 was an early computer that he wanted to get an operating system running on. He’d written PL/M or the Programming Language for Microcomputers and he would write the CP/M operating system, short for Control Program/Monitor, loosely based on TOPS-10, the OS that ran on his DECsystem-10 mainframe. 

He would license PL/M through Intel but operating systems weren’t really a thing just yet. By 1977, personal computers were on the rise and he would take it to market though calling the company Digital Research, Inc. His wife Dorothy ran the company. 

And they would go into a nice rise in sales. 250,000 licenses in 3 years. This was the first time consumers could interact with computer hardware in a standardized fashion across multiple systems. They would port the code to the Z80 processors, people would run CP/M on Apple Its, Altair’s, IMSaI, Kaypro, Epson, Osbourne, Commodore and even the trash 80, or TRS-80. The world was hectic and not that standard, but there were really 3 main chips so the software actually ran on 3,000 models during an explosion in personal computer hobbyists. 

CP/M quickly rose and became the top operating system on the market. We would get WordStar, dBase, VisiCalc, MultiPlan, SuperCalc, Delphi, and Turbo Pascal for the office. And for fun, we’d get Colossal Cave Adventure, Gorillas, and Zork. 

It bootstrapped from floppy disks. They made $5 million bucks in 1981. Almost like cocoaine money at the time. Gary got a private airplane. And John Opel from IBM called. Bill Gates told him to. IBM wanted to buy the rights to CP/M. Digital Research and IBM couldn’t come to terms. And this is where it gets tricky. IBM was going to make CP/M the standard operating system for the IBM PC. Microsoft jumped on the opportunity and found a tool called 86-DOS from a company called Seattle Computer Products. The cool thing there is that used the CP/M Api and so would be easy to have compatible software. Paul Allen worked with them to license the software then compiled it for the IBM. This was the first MS DOS and became the standard, branded as PC DOS for IBM. 

Later, Kildall agreed to sell CP/M for $240 on the IBM PCs. The problem was that PC DOS came in at $40. If you knew nothing about operating systems, which would you buy? And so even though it had compatibility with the CP/M API, PC DOS really became the standard. So much so that Digital Research would clone the Microsoft DOS and release their own DR DOS. Kildall would later describe Bill Gates using the following quote: "He is divisive. He is manipulative. He is a user. He has taken much from me and the industry.” While Kildall considered DOS theft, he was told not to sue because the laws simply weren’t yet clear. 

At first though, it didn’t seem to hurt. Digital Research continued to grow. By 1983 computers were booming. Digital Research would hit $45 million in sales. They had gone from just Gary to 530 employees by then. Gangbusters. Although they did notice that they missed the mark on the 8088 chips from Intel and even with massive rises in sales had lost market share to Unix System V and all the variants that would come from that. CP/M would add DOS emulation. 

But sales began to slip. The IBM 5150 and subsequent machines just took over the market. And CP/M, once a dominant player, would be left behind. Gary would move more into research and development but by 1985 resigned as the CEO of Digital Research, in a year where they laid off 200 employees. 

He helped start a show called the Computer Chronicles in 1983. It has been something I’ve been watching a lot recently, researching these episodes and it’s awesome! He was a kinda and wicked smart man. Even to people who had screwed him over. 

As many would after them, Digital Research went into long-term legal drama, involving the US Department of Justice. But none of that saved them. And it wouldn’t save any of the other companies that went there either. Digital Research would sell to Novell for $80 million in 1991 and various parts of the intellectual property would live on with compilers, interpreters, and DR DOS living on. For example, as Caldera OpenDOS. But CP/M itself would be done.  

Kildall would die in a bar in Monterey, California in 1994. One of the pioneers of the personal computer market. From CP/M to disk buffering the data structure that made the CD, he was all over the place in personal computers. And CP/M was the gold standard of operating systems for a few years. 

One of the reasons I put this episode off is because I didn’t know how I would end it. Like, what’s the story here. I think it’s mostly that I’ve heard it said that he could have been Bill Gates. I think that’s a drastic oversimplification. CP/M could have been the operating system on the PC. But a lot of other things could have happened as well. He was wealthy, just not Bill Gates level wealthy. And rather than go into a downward spiral over what we don’t have, maybe we should all be happy with what we have. 

And much of his technology survived for decades to come. So he left behind a family and a legacy. In uncertain times, focus on the good and do well with it. And thank you for being you. And for tuning in to this episode of the History of Computing Podcast. 

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