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NEC V20 and CP/M

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  • lowen
    replied
    Well, the "canonical" MP/M system would have been the Altos Sun Series 8000, later called the ACS 8000. With MP/M being available in 1979, and TI's first 4164's in late 1978, machines like the ACS 8000 (available late 1979) could have used 4164's......

    I once had an ACS 8000-10; I set up MP/M on it for use by my uncle's local TV repair shop, who used it until he sold it and retired in 1989. I don't recall which RAM it used right off hand, but searching on images of the ACS 8000, it would seem 4116's are in use; reference http://www.retrocomputing.net/parts/...-10_inside.jpg for a documented max RAM of 208k. (I count 13 columns of 8 chips; 13*8 chips = 104; 104 4116's = 208k.)

    The Altos 580 I have now has 192k, and it does use 4164's, but it has a much smaller PC board than the monster used by the ACS 8000-10, which completely covered two side by side 8-inch floppy drives.

    Leave a comment:


  • Chuck(G)
    replied
    When MP/M came out, I think it's a fair estimate that the most common "full up" machine had 64K of RAM; probably 4116 type DRAMs. MP/M would not have done well. There was no standard for bankswitching; everyone did their own thing. For example, on the Durango F85, we ran the top 6 bits of the CPU address through a Fairchild 64x9 bipolar SRAM--translation speed was a big issue as we were using a 8202 DRAM controller.

    That gave you up to 256K of memory space (we didn't use the 9th bit), mappable in 1K blocks. It was elegant and we used it to good advantage in our own software. It wasn't what MP/M was designed to use, although it was possible to use it--but then, we didn't design our system to run MP/M (or CP/M). We had our own multitasking OS.

    In short, this wasn't the era of standardized conventions, as you see in the PC or Mac world. There were some wild differences between vendors.

    For multitasking, there was also the one-CPU-per-user mode, as one might find on a Molecular system. The "master" CPU handled I/O, but otherwise, each user had his own 64K address space. In a bus-oriented system, such as S100 or Multibus, this makes a lot of sense. Again, not something that MP/M was designed to.

    Leave a comment:


  • krebizfan
    replied
    Compupro sold a decent number of units with MP/M. The price of $1000 might have been a bit daunting for wide spread use compared to the $175 for CP/M-80 or $300 for CP/M-86 let alone the $40 for PC-DOS. That was Compupro pricing in 1983; other vendors might have different prices.

    CP/M Plus had a good career but it was mostly with lower cost systems outside the US so got ignored in the US. Most of the interesting CP/M Plus software such as with the Amstrad were quite late to market and largely machine specific. Just as an example, see https://cpcrulez.fr/applications_util-new-word.htm Clicking on the memory requirement will bring up lists of other programs needing that much memory. It is a fast way to see the 128k and 256k Amstrad penetration. Probably similar lists for other super CP/M computers but I have not found those yet.

    Woz gets interviewed every year about some aspect of the Apple II. As long as he enjoys doing them, good for him.

    Leave a comment:


  • Jo22
    replied
    Hey, hey, I didn't mean to criticize anyone. Sorry, if it looked that way.
    I was just curious why back in these days -when CP/M still played a vital role- CP/M Plus or MP/M weren't so popular.
    There's no reason to feel urged now to retrofit anything.. Also, 22Nice is fine the way it is, imho.

    (My first CP/M machine had CP/M Plus, whereas my father used to use the previous versions..
    We still have got some old 1970s issues of "Popular Electronics" floating around, introducing that hot piece
    of software named Control Program/Monitor. )

    I wonder if Woz still gets questions about the Apple II.
    I don't know. But I bet some people keep asking him about the Apple I..
    Last edited by Jo22; May 30, 2019, 08:48 PM.

    Leave a comment:


  • Chuck(G)
    replied
    I wonder if Woz still gets questions about the Apple II.

    Leave a comment:


  • commodorejohn
    replied
    Originally posted by Chuck(G) View Post
    What do you mean "maintainer"? I wrote the bloody thing.
    And, as with any author of a useful program, you're now shackled to it for the rest of your life - this is the state of maintainerhood

    Leave a comment:


  • Chuck(G)
    replied
    I don't disdain it any more than I disdain Concurrent CP/M. It's just that the world moved on by the time that it came out.

    Leave a comment:


  • alank2
    replied
    I guess that explains why there isn't a 31NICE!!! (having a little fun at your disdain for CP/M plus...I hope you don't mind!)

    Leave a comment:


  • Chuck(G)
    replied
    What do you mean "maintainer"? I wrote the bloody thing.

    Leave a comment:


  • commodorejohn
    replied
    Things I learned today: Chuck(G) is the maintainer of 22Nice...?

    Leave a comment:


  • Chuck(G)
    replied
    22Nice, I suppose, could add as many CP/M 3.0 calls as desired, since the resident part is just a stub with a few tables. The "meat" is all x86 code. But I've never been asked to do this in (2019-1987) = 32 years. For all I know, I may have implemented a few extra calls--I haven't looked at the code in 20+ years, when I added the "user-defined code" feature.

    Leave a comment:


  • krebizfan
    replied
    They did. Somewhat. http://www.z80.eu/myz80cpm.html handles of number of post-2.2 calls and implements a few terminals if the documentation is to be trusted.

    I suspect it got a lot harder to emulate later versions since calls didn't have a matching MSDOS call to build around.

    Leave a comment:


  • Jo22
    replied
    Thank you everyone! I do now understand why CP/M 1.x and 2.2 were such a great break-trough on early micros from the 1970s.
    Tiny requirements and flexibility (CP/M was among the first portable and hardware-independable OS) and support for floppy disks.
    Meanwhile, the real, physical releases of the CP/M OS stopped being updated on most niche-PCs, so people settled for CP/M 2.2 finally.

    Though there's still one thing that I'm curious - why didn't later emulators releases catch up and continued to improve (in general) ?
    Adding CP/M Plus calls and other useful features neither harmed any compatbility, nor did it cost a cent, since these emulators were "synthetic".
    Ie. not using any physical parts or code from Digital Research. They merely implemented conventions and software APIs (or ABIs) that were compatible to CP/M-80.

    That's what puzzles me. In 1983, writing a barebone CP/M 2.2 emulator surely made sense, but by 1985 to 1989 things could have become more sophisticated.
    I mean to say, as time went on, legacy hardware was fading away, simultanously, Personal Computers became more powerful.
    Wouldn't it had made sense to allow CP/M applications to use these featues, maybe by adding a virtual CRT device and/or multiple TTY devices
    or by mapping the 16 user channels to sepparate directories on the fixed disks ?

    Leave a comment:


  • krebizfan
    replied
    A lot of Amstrad games did take advantage of the 128 kB RAM*. DR DRAW in its Amstrad incarnation required 128kB** and I suspect other Amstrad applications did as well. VisiCalc Advanced used 128 kB RAM on the Apple III and IBM PC but the CP/M versions did not get the same upgrade. UCSD Pascal was designed to take advantage of the 128 kB of the PDP-11 as did the IBM PC versions but I believe none of the 6502 or Z80 versions took advantage of extra banks of RAM.

    There was the craziness of SymbOS which need lots of extra memory and was designed to run with up to a megabyte but that didn't arrive until after 2000 so not representative of Z-80 design trends.

    * http://www.cpcwiki.eu/forum/games/games-using-128k-ram/

    ** GSX plus CP/M Plus is memory hungry

    Leave a comment:


  • Chuck(G)
    replied
    At the time of the 5150's debut, a complete Morrow Micro-Decision package was cheaper than a bare-bones PC setup. You have to remember that there was nearly a nine-year gap between the 5150 and the IMSAI 8080. A lot of technology progress was made in that time. So you have to compare apples-to-apples in this case.

    I know of at least one customer who's still running his CP/M application under 22Nice under VDos under Win10. So there's your multitasking.

    Recall also, that CP/M was a general-purpose/generic operating system--and that was the beauty. You could run it on little more than a 20K 8080 system with a single disk drive and dumb terminal. When CP/M 1.4 came out, few people had 64KB of memory available. Graphics and networking were beyond the pale of imagination, strictly the province of larger machines. Even when the first 16K-64K 5150 came out, networking was sort of a fuzzy proposition. DOS had no support for graphics. Floppy-only systems were common.

    As they say, 20-20 hindsight is easy.
    Last edited by Chuck(G); May 29, 2019, 07:10 PM.

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