Post Ar8oMHesBvd4LWhfqy by rlauzon@mastodon.social
(DIR) More posts by rlauzon@mastodon.social
(DIR) Post #Ar80azimASljLpLlVQ by tomjennings@tldr.nettime.org
2025-02-15T02:08:28Z
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#retrocomputing #cpm I'm unable to find a Digital Research CP/M 2.2 boot disk image, which seems odd to me. I'd prefer the distribution 20K system, but anything 60K or less would do.I have the disk-utilities tools installed, disk-analyze will convert DiskImage files to sector dumps OK. But I can't seem to find one that has the bootable 20K CP/M (for the Intel MDS) so I can yank off CCP and BDOS.Or, binary images of CCP and BDOS that I can assemble myself. I've looked in all the obvious repositories, cpm.z80.de, retroarchive.org, etcFile CPM.SYS on retro- just doesn't look right in hexdump.
(DIR) Post #Ar81JRQeVpq41i4Csy by hairyvisionary@fosstodon.org
2025-02-15T02:16:28Z
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@tomjennings suspect you may be looking for http://www.retroarchive.org/maslin/disks/8inch/index.html which has links to cpm-dist.td0 and cpm-dist.zip
(DIR) Post #Ar8HWZvtnx69Qry6Uq by hairyvisionary@fosstodon.org
2025-02-15T03:24:19Z
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@tomjennings am looking at CPM.SYS from cpm-dist.zip with hexdump -C and at 0x0080 I see "c3 5c 37 c3 58 37" and am thinking those are in the ballpark for a 20K system, the CCP ought to start at 0x3400
(DIR) Post #Ar8HWacnETPRZu2MM4 by tomjennings@tldr.nettime.org
2025-02-15T05:18:09Z
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@hairyvisionary aargh. OK i was doing this at the end of a long (though good!) and i too poked through with SID, but its entirely possible i will look tomorrow and it makes sense!
(DIR) Post #Ar8IXW65ePkZmQkL7A by tomjennings@tldr.nettime.org
2025-02-15T05:29:32Z
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@hairyvisionary I dont know what the td0 files are, ill look at in the daylight...But the things im looking for are not files, in the CPM context; CCP and BDOS=existed only as binary data stored in disk sectors outside of the filesystem.
(DIR) Post #Ar8JLrlTMkIPSZ6xQ8 by hairyvisionary@fosstodon.org
2025-02-15T05:38:37Z
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@tomjennings td0 is a Teledisk disk-image file, which is somewhat version-dependent and not what I think of as well-documented (though this could have improved in the last 20-30 years). That's why I looked at the zip archive.It has been a while since I thought about how to sysgen a CP/M system. My thinking is that the blob of code that gets loaded from a boot loader must have previously been loaded from stuff in a file or files. Like, um, CPM.SYS.
(DIR) Post #Ar8KptfOxTqS069g9I by tomjennings@tldr.nettime.org
2025-02-15T05:55:16Z
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@hairyvisionary The CP/M system software itself, the BDOS (disk system), outside of the utilities, resides in reserved tracks, binary only. It is/was popagated by the sysgen tools only as copied disk sectors. A new bootable system is made by cloning an existing physical disk, then changing the BIOS sectors to "your" code.Userlandf and system are linked by jump tables of fixed addresses at known locations in memory. Its utterly unlike anything modern.Hmm it needs a modern description! Today I was reading the Alteration Guide, and it took modest effort to re-understand this primitive stuff!It was smart and clever and very reliable though!
(DIR) Post #Ar8QD8MJ01yTzx7fLk by hairyvisionary@fosstodon.org
2025-02-15T06:55:27Z
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@tomjennings I actually did live through the late CP/M era, running it on a Z80 card in an Apple ][ so I got a pre-configured diskette in the box with the card and made a copy of that as my everyday booter. It wasn't 'til later that I got to read a CP/M 2.2 Alteration Guide but even that was probably 30 years ago.I am remembering reading about MOVCPM and thinking it must know where all the absolute references (e.g. JMPs and CALLs) are so it can modify them for the desired system address.
(DIR) Post #Ar8TWPRK179EL2LscS by tomjennings@tldr.nettime.org
2025-02-15T07:32:36Z
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@hairyvisionary Yeah it's been a while huh! Lol. The tools were so primitive... I will look at the CPM.SYS file more closely tomorrow. And there's got to be a DiskImage file of one somewhere...
(DIR) Post #Ar8oMHesBvd4LWhfqy by rlauzon@mastodon.social
2025-02-15T11:26:03Z
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@tomjennings My understanding is that CP/M was tailored to the hardware it was supposed to run on.That would imply that there is no generic "DR Boot Disk" but rather a "Kaypro Boot Disk", "Osborne Boot Disk", "Eagle Boot Disk", etc.
(DIR) Post #Ar9cNRDx6gkk0mr5w8 by tomjennings@tldr.nettime.org
2025-02-15T20:46:32Z
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@hairyvisionary Did you ever figure out how movcpm works? I too meant to look and never did.
(DIR) Post #Ar9cZcZgjPkOgppc8W by tomjennings@tldr.nettime.org
2025-02-15T20:48:44Z
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@rlauzon Yes you got it. The hardware specific parts are on the BIOS, custom for each machine. The other parts are the same however, BDOS and CCP (command processor).
(DIR) Post #Ar9ldjGYh5IeBluwLo by hairyvisionary@fosstodon.org
2025-02-15T22:30:18Z
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@tomjennings I did not but I think if you look at http://www.cpm.z80.de/source.html you will find a link "CP/M 2.2 ORIGINAL SOURCE" to a cpm2-plm.zip file which includes CPMOVE.ASM which looks like 8080 ASM source for something that might be itIt is AMAZING what has been allowed to escape
(DIR) Post #Ar9vMj4r8q2uDpyUaW by tomjennings@tldr.nettime.org
2025-02-16T00:19:18Z
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@hairyvisionary GOT IT!! thanks. I had another file of the same name, I worked out it's for a 60k system. But I went and got that one, after an hour of pharting around got it to boot. I don't recall any such file, CPM. SYS, do you? I assume it's a later thing, or maybe a retro culture thing to capture system tracks. I'm any case I'm up and running and I'll put all of this stuff online with explanations. Thanks so much for that!!
(DIR) Post #ArA2cvHMF8rsNSUbEO by hairyvisionary@fosstodon.org
2025-02-16T01:40:38Z
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@tomjennings I hope I helped you get there faster!I don't recall a CPM.SYS file. I remember there being a CP/M in system tracks that was the CCP and BDOS and a BIOS, and being kinda mystified about how one would change the BIOS but not really needing to change the BIOS because the hardware vendor had already done that (which is what CP/M was like in its decline, there for you to use).
(DIR) Post #ArAO21mpHdNMpy1Xbk by tomjennings@tldr.nettime.org
2025-02-16T05:40:30Z
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@hairyvisionary Interesting, thanks! I have a slight interest in pl/m, though I've only glanced and a little source code. I should probably spend a bit of time with it.
(DIR) Post #ArCejjAjq6OlQjzJom by tomjennings@tldr.nettime.org
2025-02-17T07:57:06Z
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@hairyvisionary It's so barbaric! Lol. Calculator and paper stuff, code sizes rounded up to 128 multiples. Loading Intel hex to ram and writing sectors at the hardware level. But it all works so nicely. Back on the 70s, 80s, when I knew everything already (...) I don't think I spent much time on the basic documents, beyond alteration guide and the tools; today I looked at the general docs and while it's deeply nerdly (editing binaries with ddt) theres abundant and thorough documentation. 320 pages of hand written notes and how tos. It's quite amazing. I didn't really appreciate how good they were, really. There's so much functionality in PIP.COM I had no idea. And it runs on 20k of ram....
(DIR) Post #ArFkhSdPXLlClBa7BA by hairyvisionary@fosstodon.org
2025-02-18T19:48:02Z
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@tomjennings Not only can it run in 20KB of RAM, it can run on a processor with a clock frequency of maybe as much as 2MHz (being lazy and not looking at what could actually be in an MDS800, just remembering what was in an HP2645 terminal ~1976).If your CP/M came with hardware in the 1980s you might not have got the DRI manuals. It was toward the end of the 1980s when I saw them (with a Morrow Decision I which had its own sort of interesting manuals, for the Z80 card with the MMU).
(DIR) Post #ArIbPNo8Qdu4SnmZI8 by tomjennings@tldr.nettime.org
2025-02-20T04:48:05Z
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@hairyvisionary I was an OEM then, installing cp/m on various hardware and writing utilities, starting with 1.4, then 2.2 (I'm old! Lol) I even drove to the house in Pacific Grove to pick up our OEM distribution diskette and got a quick tour of the place, and saw a demo of a chess program for the 8080 (boring now, exciting then, lol). didn't meet kildall, alas. I'm in the throes of movcpm/sysgen. Their description of the offsets and such is boggling, for something so basically simple, and I'm finding everything off by 600h, 1.5 kb, which makes no actual sense. It may look different in the morning... As things often do. It's so barbaric, but they carved such a functional system out of so little. It's kinda awesome.