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

JohnBHanson · 19th Jun 2019, 8:33 pm

for 5 inch disks HD is 500kbps @ 360rpm and DD is 250kbps @ 300rpm.
for 8 inch disks always 500kbps at 360 rpm
for 3.5 inch disk always 300rpm at either 500kbps (HD) or 250kbps (DD).

Looks like there maybe something strange in the ccp command buffer that is causing the lock up - first guess would be the conin routine. However I have tried hdform with the gemini configuration which is the same as yours and it works fine.

I am surprised that the tracks are taking so long though - it should be a few tracks per second. Remember it takes one revolution of the disk to do one side, and then another revolution to do the other side and then you will hear the step motor step inwards.

19th Jun 2019, 8:33 pm	#115
JohnBHanson Heptode Join Date: Aug 2009 Location: Worthing, Sussex, UK. Posts: 661	Re: Gemini 80-Bus System for 5 inch disks HD is 500kbps @ 360rpm and DD is 250kbps @ 300rpm. for 8 inch disks always 500kbps at 360 rpm for 3.5 inch disk always 300rpm at either 500kbps (HD) or 250kbps (DD). Looks like there maybe something strange in the ccp command buffer that is causing the lock up - first guess would be the conin routine. However I have tried hdform with the gemini configuration which is the same as yours and it works fine. I am surprised that the tracks are taking so long though - it should be a few tracks per second. Remember it takes one revolution of the disk to do one side, and then another revolution to do the other side and then you will hear the step motor step inwards.