RLL vs. MFM

To GET/USE the higher capacity per track, one must, indeed use the different controller. But the ONLY difference between a 25M MFM drive, and a 38M RLL drive is whether the DRIVE can reliably handle a higher flux density recording. They are quite literally the same drive, but the MFM drive is not certified/rated for the higher density recording. Many people would try to go the other way, and use MFM drives with RLLcontrollers. They would proudly declare that "IT WORKS PERFECTLY". And later complain about "those crummy Seagate drives" when they found out the hard way that drives that weren't RATED for RLL recording were often NOT capable of doing it RELIABLY. Think in terms of "could you use a diskette that is rated for double density, if you are going to record single density?" -- Grumpy Ol' Fred cisin(a)xenosoft.com