If you really want both types of floppy drive, the Teac FD-505 is a combination 3.5"/5.25" floppy drive that fits in a single 5.25" half-height drive bay.



(Tip: When you go to connect your floppy drive ribbon cable to it, if you want the 3.5" to be drive A:, use the connector after the twist. If you want A: to be the 5.25", use the one before the twist).

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Here's a link to some 8088/V20 chip pics:

http://www.shvets.com/genna/CPUs/8088/index.html