<I am really glad to find I can use the ST-251 in my DEC <Pro 380 instead of the Quantum Q540, since the later drive <is rarer, older, and perhaps (in my experience) not too <reliable. And has a smaller capacity, of course, and is <a full-height drive. The ST251 is well known for it's bad bearings and spindle problems. The Q540 is known for running forever. The later know as a RD52 is very common and very hard to kill. I have about 8 of them (all good). Generally I will not use a st251 again... I spent to much time helping PC support at DEC with disk failures in VAXmates (st251s aka RD32) where the older st225 was rock solid. <Is there a better drive (MFM) with equivalent geometry? <(820 cyls, 6 hds, 17 sec) or maybe with 6+ heads and 820+ <cylinders (that might work, too?). Half-height would be <nice, like the 251, because if I ever get another HD <controller card, I can put two drives in my Pro 380 (only <one drive per controller card, and supposedly only one <per Pro chassis, but the 251 probably uses a lot less <power than the Q540, so two drives should be OK). the q540 is 8x512 (31mb)... and the 251 is 6x820 (40mb). Also the 540 is several times faster (voice coil VS Stepper). Allison