PCjs Machines

Home of the original IBM PC emulator for browsers.

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IBM PC 20Mb Hard Drives

PCjs includes 20Mb drives in selected IBM PC AT and COMPAQ DeskPro machines, because both those machines support a 20Mb Drive Type with the following drive parameters:

615 cylinders
4 heads
17 sectors/track

yielding a capacity of 21,411,840 bytes (615 * 4 * 17 * 512), or 20.42Mb (since PCjs considers 1 megabyte to be 1,048,576 bytes).