Does anyone have a working Altos 8000 with 8500 board *and* a working hard drive?

[FozzTexx]

A couple of weeks ago I finally came back around to working on my Altos 8000, after seven years of sitting on a shelf unused. Mine uses an 8500 model board, and came with a single floppy and an SA1000 10MB hard drive and the hard drive controller. I've managed to get it booting into the ROM monitor (v6.05, md5sum 05caffade2b572fb50b4234b5faadd88), and from there I can boot a CP/M 2.24 floppy image I found on the archive sites. No other disk image I've found online seems to be able to boot. I also was able to get a copy of a 2.26F diagnostic disk and a 2.26K diagnostic disk. The 2.26F disk I found boots, but is missing all the tools other than HRDINIT8.DIA. The 2.26K disk has all the tools but doesn't boot. With a little bit of trickery with ImageDisk by writing the 2.26K out to an 8" floppy first, then telling ImageDisk to only write the first two tracks of the 2.26F image, I can get the 2.26K to boot. I was able to go through all the diagnostics on the disk (and found I had a single bad RAM chip), and most everything checks out.

However the next thing I'd like to do is to install MP/M II to a hard drive (if I ever find Altos MP/M II disks anyway). My plan is to use David Gesswein's pdp8online MFM emulator with the SA1000 adapter to act as the hard drive. I've tested out the MFM emulator on my Victor 9000, and it works fine. But the problem is that the SA1000 drive I have is dead (it spins up but never tries to move the head) so I can't make a copy of what's on it, and neither the HARDS8.DIA tool nor the HRDINIT8.DIA tool seem to work so that I can initialize a blank drive. Neither tool seems to ever actually select the drive. I put a logic analyzer on the drive and head select pins, and I can see activity from the ROM at boot, as well as see the "select" messages from the emulator, but the tools never do anything. It's like the tools are expecting a different controller than the one I have.

My controller is very similar to the "version 2" that is in the schematics I've found, but is a little bit different. On the schematics they constructed their own OR gate from a 74ls14 and 74ls00 (at 2B and 2C), while on my board it uses a single 74ls32 (at 2B). I'm wondering if maybe my controller is enough different that the tools don't work with it, or if maybe the diagnostic disk images are just no good.

But that leads to me my question, does anyone have a surviving system using the 8500 board and you're able to boot from a hard drive, emulated or otherwise? I'm hoping if someone does then maybe we can figure out a way to get a copy of the drive in a format that I can use with the MFM emulator.

 

[djg]

But the problem is that the SA1000 drive I have is dead (it spins up but never tries to move the head) so I can't make a copy of what's on it,

Drive may still be recoverable with more work. Is it a Shugart SA100# drive or a different make?

 

[FozzTexx]

Is it a Shugart SA100# drive or a different make?

It's a 10MB 1004.

Drive may still be recoverable with more work.

Possibly, but it will probably be a lot of work, and I'm not holding my breath that I'll ever get any data from it. I do intend to come back to it, but I could already see just going through the troubleshooting steps was going to be a very long project in itself, and sourcing components might be challenging.

 

[FozzTexx]

After spending a bunch of time disassembling the HARDS8 tool and messing around with setting breakpoints and trying to make sense of the convoluted logic of both the hard drive controller and the software, I decided to take another approach. I went through all the 74xx chips on the controller board, pulling them out one at a time, popping them into the BackBit Chip Tester, and seeing what it would report. It reported three chips as bad: one 74LS04 and both 74S51 chips. I was able to confirm the 74LS04 was bid using the MiniPro, and I suspected that it was wrong about the 74S51s. After swapping only the bad 74LS04, the HARDS8 tool saw the MFM emulator and happily formatted it!

I can now boot CP/M 2.24 from floppy and copy files to the hard rive. But I have no way to copy an operating system to it. Apparently the functionality to do that was removed from the v3.7 version of HARDS8 which is on the 2.26 diagnostic disk. Why would they do that? There's nothing on the 2.26 diagnostic disk that replaces the functionality that was removed. It's possible that the 2.26 CP/M boot disks have those features, but it seems that Altos 2.26 CP/M was never archived, so those tools are long gone.

What I really want to put on the hard drive is MP/M II, which also seems that those disks have been lost to time (based on the numerous requests here that people have had on these forums for the Altos MP/M II disks and never receiving a reply). If I'm going to have to do a lot of tinkering and programming in order to get CP/M on the hard drive, I'm not going to bother and I'll fight with trying to get MP/M II on it instead and figure out what I need to do to make an Altos compatible XIOS.

But I've made quite a bit of progress because now I've got my Altos seeing a working hard drive!