UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Gemini 80-Bus System

JohnBHanson · 20th Jan 2020, 10:23 am

I think you want interleaved. It actually does not matter what CP/M believes it is actually what is recorded in the file that is important and that is defined by the geometry statement in the .cfg file for the emulator.

QDDS format is 80 tracks, 2 sides and 10 sectors per track. However CP/M does not understand sides and hence the bios re-maps the side count by doubling either the number of sectors of the number of tracks. When the bios drives the hardware it actually drives it as 80 cylinders 2 sides and 10 sectors per track and that is what you need for your floppy setup.

The next issue is the file format should be consistent for the gotek and the xbeaver emulator. This is controlled by the geometry parameter depending on the letter 'S' being present. In raw format without the S option the order of tracks in the file is cyl0side0 cyl0side1, cyl1side0, cyl1side1. Each track consisting of sectors 0..9 in order.

see routine flp_linear_block in floppy.c for details.

So I think you need interleaved set for your file layout - which appears to be also the default.

I hope that helps.

20th Jan 2020, 10:23 am	#346
JohnBHanson Heptode Join Date: Aug 2009 Location: Worthing, Sussex, UK. Posts: 661	Re: Gemini 80-Bus System I think you want interleaved. It actually does not matter what CP/M believes it is actually what is recorded in the file that is important and that is defined by the geometry statement in the .cfg file for the emulator. QDDS format is 80 tracks, 2 sides and 10 sectors per track. However CP/M does not understand sides and hence the bios re-maps the side count by doubling either the number of sectors of the number of tracks. When the bios drives the hardware it actually drives it as 80 cylinders 2 sides and 10 sectors per track and that is what you need for your floppy setup. The next issue is the file format should be consistent for the gotek and the xbeaver emulator. This is controlled by the geometry parameter depending on the letter 'S' being present. In raw format without the S option the order of tracks in the file is cyl0side0 cyl0side1, cyl1side0, cyl1side1. Each track consisting of sectors 0..9 in order. see routine flp_linear_block in floppy.c for details. So I think you need interleaved set for your file layout - which appears to be also the default. I hope that helps.