[vcf-midatlantic] Seattle Gazelle question

Richard Cini rich.cini at gmail.com
Sat Mar 18 16:50:21 EDT 2017

All –


                Back in 2014, I posted a message to the group about the Seattle Gazelle. I don’t have one, but I was basically trying to re-create it using the boards I had in-stock. Jim Scheef sent me a reply back then, but I wanted to follow-up with the whole group on this since I only just located the needed support board (300F model).


                I think I have all the pieces now: SCP 8086 board, SCP 300F support board, CompuPro RAM22 (128k), and the Cromemco 16FDC controller. I’m using the 16FDC because the source code for the v1.5 SCP BIOS has a compilation switch for it (the other options are Tarbell, SCP and Northstar) and I didn’t have the others. All of the board jumpers are “default” per the manual, other than disabling the RDOS on the 16FDC.


                This week, I put everything together and the boards work individually but not together (the 16FDC tests OK with the built-in RDOS and a Z80 board). I’ve confirmed basic things like port locations and the like match the v1.5 ROM. I’ve also done some manual testing – I can turn the drive motor on and off by outputting port I/O commands from the monitor, for example, so I know that intra-board communications work.


For drives, I have available to me TM100-2A (5.25” DSDD) and Qume QT242 (8” DSDD). The drives test good with a PC using the default jumpers (I use a floppy adapter board from DBIT for the 8”; I now have MSDOS 6.22 on an 8” disk ☺). Straight floppy cables; DS0 strapping. The TM100 (SSSD version) is mentioned specifically in the Cromemco manual, but the Qume is not.


When issuing the “B” (boot) command in the SCP ROM, there is no drive activity at all. Controller-specific code is in two places – the monitor ROM (for the bootstrap) and in the DOSIO module. The ROM version I have is for the Cromemco board, so it should work. I also have disk images so eventually I can make a bootable 8” disk if I can fix the rest of it. So, maybe a few basic questions:


·         Have I missed anything in the above?

·         What drives were used in the Gazelle and did SCP really use a controller other than the SCP one?

·         In the system VCFMA has, what drives and controller are used?


Thanks again for any help.





Rich Cini





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