On Tue, 27 Dec 2022, Chris via cctalk wrote: Am I misunderstanding something? (or over-reacting to a typo?) 8 bit ISA cards, for 5150/5160 have 62 contacts. not 34 I thought that the Northstar Dimension had same/similar 16 bit ISA (5170) is 98 pins? (including the 62 pin bus) Apple 2 is 50 S100 is 100 SA400/450 (5.25") floppy interface is 34 contacts. SA800/850 (8") interface is 50 contacts

On 12/26/22 18:19, Chris via cctalk wrote: Huh?   Exactly what should it do for file I/O? --Chuck

I haven't followed the full thread here, but perhaps this might help: when I ported DestinyHunter (destinyhunter.org) from the 6502-based PET to the IBM PC, I gathered some notes on that process here https://destinyhunter.org/ibm-5150-development-notes/ Basically: programming on an actual vintage MS-DOS system is very painful these days. For starters, the 8.3 filenames and lack of COPY-PASTE. True, there are some vintage editors that will have a form of copy-paste. Another issue is some of those old editors are limited to 32KB or 64KB files (which with comments, sometimes you might get to pretty large files), and such old editors might not have multi-file support (like having .h and .c open at the same time). I programmed many years in the "old DOS days" with 8.3 filenames - reliving that wasn't for me. BUT, it is do-able. I did try Turbo C 2.0 to make a real-mode .com (the notes in the page setup a 486-emulation in 86BOX with a DOS 6.0 configuration). Since I had a project that already used long filenames, that was another reason I wanted to cross-compile from a modern system instead. If all the existing code was already in 8.3 filenames, maybe it would have been less of an issue. But in any case, the modern system is faster, so you can experiment and compile things in a few seconds -- but then you have to transfer the resulting binary to your vintage system (I was able to use FTP, but I can understand that' not being easy for everyone). As another option: I came across the WATCOM C/C++ compiler, but (AFAIK) it's no longer maintained and getting a "reliable" download of it was a challenge. All I recall was I ended up using version 1.9 instead of 2.0. It is an IDE of sorts, though I mostly still used an external editor (notepad++). I can't recall why I didn't use Lattice - maybe it/was Commercial? Another compiler is the Intel iC-86, but you end up having to use the Borland TLINK anyway with that. NOTE: I think both Turbo C and WATCOM C have code generation options for 80186 - although offhand I can't think of any specific code that would need/use 80186 features. And each of these compilers does have a slightly different variation of C (with some settings dials inside on how compliant to be). Another note: despite using _TINY_, Borland C is still going to make an EXE - you have to use Microsoft DOS 2.10 - 3.21 to run EXE2BIN to convert it to a .com. The next mess is "standard libraries." Borland was great, but they royally confused a whole generation of developers on what the "standard C library" actually meant. Like, conio.h is not standard. But regardless - when implementing the "C standard library" for disk I/O, no one would be re-implementing FAT -- that'd miss the whole point of having a "DOS". They'd implement it in terms of software interrupts - that hopefully were compatible between PC/DR/MS-DOS. "Self Booters" (like early versions of Zork, Microsoft Flight Simulator, early versions of King's Quest) had to implement their own file systems (and it's why they aren't easy to copy, since they use a non-MS-DOS format). Thinking about it now, I think making a self-booter disk of DestinyHunter might be an interesting challenge. For reference, some notes are as follows: https://www.cs.uaf.edu/2011/fall/cs301/lecture/11_18_bootblock.html http://philipstorr.id.au/pcbook/book1/post.htm That is, the IBM PC BIOS is pre-programmed to examine the first sector for code, and do the work of copying 512 bytes to RAM and running it. What you choose to do in that boot loader is then up to you (or the OS) -- which can't be any MS-DOS interrupt calls. I'm not sure what existing code could be borrowed to read additional bytes from the disk (an annotated disaassembly of the BIOS, or examining the MS-DOS code in github maybe as a starting point). Nothing in the "standard" library of Borland Turbo C or WATCOM C, etc. really helps here (none of the fopen, fscanf, stuff). So it's not that the compiler you're seeking doesn't exist -- but some "off the shelf" utility functions doesn't readily exist. You'd have to borrow or re-implement much of what MS-DOS is already doing (if the 180KB format was ok). Again, the early MS-DOS source code is out on github as a starting reference... As far as writing it specifically to the first sector of a 5.25" disk -- I never found a "USB adapter" for a 5.25" disk drive; plenty for the 3.5" drives, but maybe the 525" drw too much power for USB?). Good Luck! On Mon, Dec 26, 2022 at 8:20 PM Chris via cctalk <cctalk(a)classiccmp.org> wrote: