RetroChallenge 2024

[granz]

Well, it's October again, and that means RetroChallenge! Hurray! 

Last year's challenge found me playing around with MS-DOS every day (https://zappbots.altervista.org/forum/viewtopic.php?f=32&t=452.) So I decided to continue with the Operating System theme, and will be working on MS-DOS' predecessor CP/M-86 (https://en.wikipedia.org/wiki/CP%2FM-86.) While I have played around with CP/M previously, it was for the 8-bit systems rather than the 16-bit(ish) PC.

So, here we gooooo...

[granz]

Day 1:

I actually should have posted this earlier (but life gets complicated) but I was working on this back around July.

Here are the notes that I wrote about my RC-2024 project:

Run CP/M-86

Prep:
- Obtain CP/M-86 on 720K floppies
- Back up SupersPort (Zip drive)
- Copy Zip S/W to floppies
- Format HD
- Get Arduino PDP-8 working with RS-232
- Setup BBS (on Pi Zero?)

Operation
- Boot to CP/M
- Use HD from CP/M
- Boot to CP/M from HD

Usability
- Install editor/word processor (WS?)
- Install Pirx Commander
- Install other S/W
- Port FreeDOS Edit to CP/M-86

Development
- Install BASIC (w/ peek, poke, inp & out)
- Write non-trivial program (CardIAC emulator?)
- Install C (to port FreeDOS Edit)
- Develop w/ PicoMite
- Develop w/ ATtiny

Communication/Networking
- Talk to Arduino PDP-8 or PC
- Talk to BBS (via wifi)
- Get (write?) browser
- Transfer files to/from network server

Well, we shall see how far we can get on this over the next 31 days. 

[granz]

Post #2

So, the first thing to do is to get a copy of CP/M-86. Since my computer only has a single 720K 3.5" (although also with a 20MB hard drive,) I needed the 720K version of CP/M-86 For The IBM PC.  The Digital Research Binary Files page at http://www.cpm.z80.de/binary.html has a copy, so let's see how that works.

First, we download the .ZIP file and extract it. CP/M does not use the FAT disk file format that MS-DOS (nor Linux floppy format) does, so we need to copy those files over to my SupersPort. In addition, since I do not know if my SupersPort has the driver files for my Zip drive, I will copy those files onto another disk. Then I will just run the extraction program to create a CP/M-86 boot disk on that floppy disk. Thankfully, Linux does not have any trouble with reading, or writing, 720K floppy disks on my external USB floppy drive. Actually, in playing with my Tandy 600, I found out that Linux plays well with 360K 3.5" disks as well.

So, while copying the files over to the SupersPort, I decided that I would need a bootable floppy, so that I can restore the SupersPort back to the way it was. When I tried to format a boot disk, it started formatting at 360K! Bummer! I had forgotten that I had removed a DRIVPARM command from CONFIG.SYS – this is necessary for some PCs to enable 720K formatting on the older 3.5" drives. I had hunted this down earlier, and had found it at: https://forum.vcfed.org/index.php?threads/headstart-lx-40-anyone-know-of-it.23880/. The entire thread covers this config, but my confirmation came in reply #6 (about the SupersPort.) So, now I just edit my CONFIG.SYS, reboot and I'll be able to create that MS-DOS 6.22 bootable floppy disk. After that, I'll copy the CP/M-86 install, and create the CP/M-86 boot disk.

Till' Monday...