1.2M HD / 300kbps / single-density

Christian Corti cc at corti-net.de
Mon Mar 19 05:05:18 CST 2007


On Sun, 18 Mar 2007, Dave Dunfield wrote:
> To verify that the drive was good, I hooked it up and tried
> to read/write some disks - to my surprise I could not do
> single density (at 300kbos). Tried a couple other HD drives
> with the same result. On a hunch, I modded it to 300rpm, and
> sure enough, I can read/write single-desnity fine at
> 300rpm / 250kbps.

That's a known problem with many FDCs, they can't handle FM at 150 kBit/s, 
only at 125 kBit/s. So either jumper your drive for dual speed (so it will 
spin at 300rpm for 125/250 kBit/s and at 360rpm for 250/500 kBit/s) or 
jumper it for single speed at 300rpm (therefore making a 5,25" drive look 
like a 3,5" drive to the BIOS).

Christian


More information about the cctalk mailing list