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Origins of the Modern PC
Homncruse writes "ComputerWorld dispels myths about the history of modern day computers — or, more appropriately, the invention of the first microprocessor. Contrary to popular belief, 'the [Intel] 8008 was not actually derived from the 4004 — they were separate projects.' In fact, the 8008 concept didn't originate from Intel (though they were eventually granted IP rights.) The article goes on to explain the events leading up to the invention and first intended use of the 8008 (a predecessor to the 8086, etc.), and how Intel was initially uneasy about the venture."
I enjoyed the Blueprint of the Datapoint 2200 enclosure, showing the crowded interior. I guess the caption writer has never seen the inside of a mechanical calculator. Imagine an object the size of a small desktop PC enclosure, entirely stuffed with mechanical linkages. It's truly astonishing.
By comparison, a handful of circuit boards stuffed with SSI and MSI chips was delightfully simple. No moving parts! No lubrication! No wear!
They weren't overclocking. They were just trying to put it into a small enclosure. And do you have a better suggestion for cooling?
The Z80 was in between as well.
If I recall , it was object code compatible with 8080, although the register names were different , it had another alternate set/ copy of its registers which could be swapped between .
or at least one of the first few, was also a PC - a Programmable Controller used for controlling industrial equipment or processes. Eagle Signal's Industrial Controls Division's CP700 Eptak modular system was 8080 based, and some of the early software was developed on Datapoint terminals. They paid $365 each for the first 8080s - an 8080A now goes for $1 or less. Eagle also ran what might have been the first college-level microprocessor course in-house for employees. It was taught by a prof from Iowa State and covered the 8080, 6800 and 6502. The original 8080s also required an external clock as the two pins across which you were supposed to be able to attach a crystal wouldn't osciallate. Don't recall the clock speed - 1MHz initially I think - but the 4MHz Z80 was considered a major speed advance.
Eagle Signal also had a Traffic Control Division (you can still see their traffic light control cabinets on street corners) that was one of the first 8008 users, and also used Data General Novas for traffic controls.
Neither Eagle Signal division exists any longer. Both were owned by Gulf+Western Industries in the early 70s and located in Davenport, IA. Both divisions eventually moved to Austin, TX. Danaher now owns the industrial controls product line, and probably makes more profit selling Eagle's HP5 electro-mechanical timers than its electronic products, which was where the company's profits always came from.
Upwardly compatible opcodes was the overarching reason why, in that era, the 8086 was considered a true descendant of the 8080, and the 8080 was considered the true descendant of the 8008.
Remember we are talking about an era when Assembly Language was the highest level of programming abstraction available on the early micro computers. The compilers that converted AL to binary machine language ran on minicomputers, were state of the art, expensive, hard to acquire, and difficult to use. Developing under these conditions, and attempting to fit working programs into 4, 8, or even a glorious 16 kilobytes of RAM, was an art form that no one has had to practice in more than 30 years.
There was a tremendous advantage in developing a chip that allowed extension of the existing AL compilers without total rewriting, and allowed the AL programmers of the day to build upon their old skills. That some of the routines developed for the 8008 would also run on the 8086 / 8088 was a fringe benefit.
Disclaimer: while I was writing my first "HELLO WORLD" programs in Fortran on punch cards at the time the 8008 was put on the market, my first PC was an Apple II+ (about 8 years later) and I learned 6502 Assembly rather than 8086 code. I have since managed to forget all those old skills. Good riddance! It is much better to scratch out new ideas in Perl, and then if there is some reason to optimize, get a code monkey or two to do the low level work.
attempting to fit working programs into 4, 8, or even a glorious 16 kilobytes of RAM, was an art form that no one has had to practice in more than 30 years.
You know, there are still some of us who routinely develop software for controllers in weather probes, dive computers, GPS chips, and so on... there definitely are times where 16 kilobytes is glorious.
The Z80 was an upwardly compatible extension/clone of the 8080A. The Z80 was designed by Federico Faggin at Zylog after he left Intel. Faggin had previously designed the 8080 when he was at Intel. So the Z80 is a derivative, not "in between" any of the Intel CPUs. Interestingly, Zylog licensed the Z80 design royalty free creating a robust second source market. Z80s dominated the 8-bit CPU market in the late 1970s.
Statesman
Thank you for correcting my oversight. Embedded device controllers and similar applications are a world of their own. Forth is glorious: the first programming language commercially implemented on the 8086 back in the day, and still, when you count up all the cars and trucks, elevators and diesel-electric locomotives, the most commonly used computer language in the world.