IBM 5150 PC disk drive questions

Not from IBM. After the PC was released, IBM couldn't see any reason why anyone would want more than two drives. So, they "fixed" that on the AT, by only providing for two drives, at the same time that they began supporting two different kinds of drives. Soon 3. Soon 4. So, the PC, with only one kind of drive available, had hardware support for 4 drives. Soon thereafter, with need for three different kinds of drives, IBM had hardware support for only two drives. (It is not necessary to have both 720K AND 1.4M on the same machine (other than for copying), but 1.2M could NOT completely subsume the need for 360K (if you interchanged with others)). Aftermarket disk controller cards remained available that would support 4 drives. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com 2210 Sixth St. (510) 644-9366 Berkeley, CA 94710-2219