4 ms·

But we also didn't need as much memory. The memory resident portion of CP/M was only 2kb, and that is with some inefficiency because it was necessary to stick w

But we also didn't need as much memory. The memory resident portion of CP/M was only 2kb, and that is with some inefficiency because it was necessary to stick with the 8080 instruction set. Just recently there was an article on HN about the passing of Randy Suess, who along with Ward Christensen created the first real BBS. The other part that often isn't recognized, is the work that Irv Hoff did to re-write the memory resident part of CP/M, so that it not only did everything that a operating system needs to do, but could also accept remote connections, deal with a modem, and have some (very rudimentary) security. All in 2kb. That's amazing.

retrac 7y ago
> But we also didn't need as much memory. Another way to look at it is that we only did the things we could do with such little memory. CP/M is a marvel of size-constrained code, but it's also crude in the extreme. A multitasking virtual memory system with a decent file system and an optimizing high-level language compiler -- what most developers would consider the bare minimum for being civilized today -- really relies on having about a megabyte or more of RAM in practice. Consider the web, one of the "killer apps" for computing in general. It's not hard to imagine implementing something like modern packet-switched networking and basic text-only hypertext documents, with a computer which can only do about 100,000 instructions per second. But doing it with only 4 or 16 KB of RAM, though? Just this comment is 843 bytes.
- whyenot 7y ago
  MP/M didn't have virtual memory, but it had everything else on your list, was released in 1979, and had a minimum memory requirement of 32kb. In the mid 1980s, I ran a four line BBS on an Atlas ACS8000-14 running MP/M. I wrote the BBS in DR CBasic. I attempted to port it to Turbo Modela-2, another high level language, but the IDE was so buggy that I eventually gave up (being female and a teenager, there was also a lot of social pressure not do computer stuff).
- wbl 7y ago
  The PDP-11 had 16k.
  - retrac 7y ago
    Yes, the original PDP-11/20 came with as little as 8 KB of RAM. But early operating systems and languages for the PDP-11 were painfully primitive. We're talking paper tape and assembly only, in 1970 on the base 8 KB of RAM. On the other hand, consider the memory requirements of UNIX v7. It required separate instruction and data address spaces using the PDP-11's virtual memory features, as neither the kernel nor some of the compilers would fit into only 64 KB of data/code. 128 KB was necessary to boot a minimal single user system. 256 KB was realistically required to run multiple processes. By 1979, that's software requiring 16x as much memory as in the base configuration of the original PDP-11 of 1970, just to boot. It just would not have been possible to write something like v7 UNIX in only 16 KB of RAM.
- jacquesm 7y ago
  You are writing all this in (1) someone's obit, and (2) even though you preface it that you don't want to detract from their achievements you do nothing but and (3) you do so with a couple of decades of hindsight. Yes, things have changed. No, without the microprocessor we would not have all the goodies we have today. What 'most developers consider the bare minimum for being civilized today' simply was not available to 'most developers' at the time, we were happy with what we had. And in some ways I wished developers today would not be so spoiled that they allocate megabytes like it doesn't matter because it does add up and then suddenly it does matter.
  - retrac 7y ago
    As to your first point, I suppose I kind of assumed the readers here were familiar with MOS Technology and their work in integrating DRAM onto the same die as a processor, along with advances in ROM manufacture, and the general push to system-on-a-chip integration. To be clear, Chuck Peddle also helped design chips like the RRIOT (1 KB of ROM, 64 bytes of RAM, a parallel IO port and a timer). A machine like the KIM-1 (also of Peddle's design) would not have been possible without the RRIOT chip, anymore than without the 6502. I just find it skewed that we all focus on the microprocessor he designed, when a chip like the RRIOT was just as important. Microprocessors are pretty nifty indeed, but they'd be useless without IO and memory just as cheap and small to go with them.
    - jacquesm 7y ago
      The crowd on HN ranges from people born after the millenium to those that cut their teeth on 8 bitters and even older people. I started out on the KIM-1, I think you mean the 6530. Your comment above reads a lot nicer than the ones preceding it, and yes, they needed IO and memory but without them that IO and memory would have never happened and the processors were the flagships of their respective companies.

retrac 7y ago

> But we also didn't need as much memory. Another way to look at it is that we only did the things we could do with such little memory. CP/M is a marvel of size-constrained code, but it's also crude in the extreme. A multitasking virtual memory system with a decent file system and an optimizing high-level language compiler -- what most developers would consider the bare minimum for being civilized today -- really relies on having about a megabyte or more of RAM in practice. Consider the web, one of the "killer apps" for computing in general. It's not hard to imagine implementing something like modern packet-switched networking and basic text-only hypertext documents, with a computer which can only do about 100,000 instructions per second. But doing it with only 4 or 16 KB of RAM, though? Just this comment is 843 bytes.

whyenot 7y ago
MP/M didn't have virtual memory, but it had everything else on your list, was released in 1979, and had a minimum memory requirement of 32kb. In the mid 1980s, I ran a four line BBS on an Atlas ACS8000-14 running MP/M. I wrote the BBS in DR CBasic. I attempted to port it to Turbo Modela-2, another high level language, but the IDE was so buggy that I eventually gave up (being female and a teenager, there was also a lot of social pressure not do computer stuff).
wbl 7y ago
The PDP-11 had 16k.
- retrac 7y ago
  Yes, the original PDP-11/20 came with as little as 8 KB of RAM. But early operating systems and languages for the PDP-11 were painfully primitive. We're talking paper tape and assembly only, in 1970 on the base 8 KB of RAM. On the other hand, consider the memory requirements of UNIX v7. It required separate instruction and data address spaces using the PDP-11's virtual memory features, as neither the kernel nor some of the compilers would fit into only 64 KB of data/code. 128 KB was necessary to boot a minimal single user system. 256 KB was realistically required to run multiple processes. By 1979, that's software requiring 16x as much memory as in the base configuration of the original PDP-11 of 1970, just to boot. It just would not have been possible to write something like v7 UNIX in only 16 KB of RAM.
jacquesm 7y ago
You are writing all this in (1) someone's obit, and (2) even though you preface it that you don't want to detract from their achievements you do nothing but and (3) you do so with a couple of decades of hindsight. Yes, things have changed. No, without the microprocessor we would not have all the goodies we have today. What 'most developers consider the bare minimum for being civilized today' simply was not available to 'most developers' at the time, we were happy with what we had. And in some ways I wished developers today would not be so spoiled that they allocate megabytes like it doesn't matter because it does add up and then suddenly it does matter.
- retrac 7y ago
  As to your first point, I suppose I kind of assumed the readers here were familiar with MOS Technology and their work in integrating DRAM onto the same die as a processor, along with advances in ROM manufacture, and the general push to system-on-a-chip integration. To be clear, Chuck Peddle also helped design chips like the RRIOT (1 KB of ROM, 64 bytes of RAM, a parallel IO port and a timer). A machine like the KIM-1 (also of Peddle's design) would not have been possible without the RRIOT chip, anymore than without the 6502. I just find it skewed that we all focus on the microprocessor he designed, when a chip like the RRIOT was just as important. Microprocessors are pretty nifty indeed, but they'd be useless without IO and memory just as cheap and small to go with them.
  - jacquesm 7y ago
    The crowd on HN ranges from people born after the millenium to those that cut their teeth on 8 bitters and even older people. I started out on the KIM-1, I think you mean the 6530. Your comment above reads a lot nicer than the ones preceding it, and yes, they needed IO and memory but without them that IO and memory would have never happened and the processors were the flagships of their respective companies.