[TUHS] Codata progress update

Hi, it's time for an update on our progress with the Codata machine. The serial interface problem was not caused by a defective transceiver chip (which I found out after buying a couple…), but by an extreme amount of noise on the (quite long and old) serial cable we used to connect the machine to the PC acting as a terminal. Using a USB to serial adapter and a short 9-to-25-pin adapter cable solved this problem. Well, try the obvious things first (using a scope helped). The second CPU board also works, so we could build a complete second machine with our spare boards if we have another multibus backplane... We could get the machine up and booting from the first 8" hard disk last Friday. Luckily, an old version of Kermit was installed and we were able to transmit a large part of the root file system from single user more - especially the Unix kernels, driver sources, the build directories for the kernel, include files and the build directory for the standalone boot floppies. All with a speed of 500 bytes/s (9600 bps serial line minus kermit overhead). cksum was used to confirm that the files were transferred correctly (this was the only checksumming tool that was available on the Codata, I didn't want to mount the fs read-write and compile software before completing the backup). I had to shut the machine down on Friday evening (security policy that kicks you out of the building here), since I didn't want to leave it running unattended over the weekend. Unfortunately, the disk seems to have developed a bad sector in the autoconfiguration region (the system seems to be quite modern in this respect). The kernel can be booted successfully, but it refuses to mount the root fs, complaining about a timeout. There seems to be a complete root file system on the second disk (the firmware is able to read files from the disk, but it doesn't offer a feature to list directories…), but the kernel on the second disk also is hardwired to mount its root fs from the first disk. Trying to connect disk 2 as disk 1 resulted in a non-booting system... The good news is that both root file systems seem to be reasonably intact so far, I can read text files from the boot monitor. So our next step to backup the rest of the system is to build an emergency boot floppy. At the moment, however, the Codata refuses to talk to its floppy drive. The machine has a Multibus FD controller with its own 8085 CPU and a uPD765, connected to a Toshiba 5.25" DD floppy drive (720 kB, 80 tracks, 9 sectors of 512 bytes), the model identifier is DDF5-30C-34I (printed on the motor assembly). I couldn't find any information on that drive online, so I hesitate to simply connect a more modern drive due to possible pinout differences. I also found out a bit more on the SMD disk controller. It seems to be an OEM variant of the Micro Computer Technology MCT-4300 controller. The only place I could find this mentioned was in a catalog of Multibus boards on archive.org. It has its own driver (cd.c), there is a separate one for the Interphase 2180 and an additional one for the Codata MFM controller. So, if you happen to have any information on the Codata floppy controller, the Toshiba floppy or the MCT-4300 SMD disk controller, I would be happy to hear from you... -- Michael