2.4Mb 5 1/4" floppy drive?

On Fri, 20 Sep 2002, Joe wrote: Interesting that those guys refer to them as "high density", but refer to the 1.2M as "double density" I'm not familiar with them, at all. I don't think that IBM ever released a machine with them, like their 3.9" drive. It does not appear to be supported in any version of PC-DOS. But a simple block mode device driver is all that would be needed. There have been a few different higher density 5.25" systems, such as the one that Kodak bought out. But I don't think that this is the same one. There are two obvious ways to get that capacity. One would be to halve the track spacing to 192 TPI. That would give you 160 tracks per side, with 15 sectors per track with 512 bytes per sector, and would permit using "regular" 600 Oerstedt ("1.2M") diskettes, but possibly with some problems with diskettes that aren't quite up to it. (like the problems that Tony has with using "360K" diskettes for 720K 5.25.) It would require a smaller step track to track, and a narrower head (about 1/2 mm wide track v the 1/6mm wide track of the 1.2M) The other way to do it would be to use a barium ferrite diskette (5.25 version of the 2.8M 3.5"). That would require a special head for "vertical recording", and would require a 1000K bits per second data transfer rate (same as for the 2.8M 3.5"). Then it would still only be 80 tracks per side, but instead of 15 512 byte sectors, it would be able to fit 30 (or maybe even 32) 512 byte sectors on each track. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com PO Box 1236 (510) 558-9366 Berkeley, CA 94701-1236