reasons to keep a Turbo XT clone.

On Wed, 13 Feb 2013, Chris Tofu wrote: SS/DS makes no difference. The 5150/5160 controller and ALL other PCs ALL support side select. SD(FM)/DD(MFM) DOES make a difference. The stock 5150/5160 controller is hardwired DD(MFM). It takes a little work to modify the board to un-hardwire to make that switchable. OTOH, some later controller chips, such as the 37C65 variant of the 765 do that SD(FM)/DD(MFM switch in software! Those are worth seeking out. The stock 5150/5160 can handle the data transfer rate (250K) for 8" SD, but not the data transfer rate (500K) needed for 8"DD. Consider a 5170 style controller (and therefore 5170 machine), OR MAYNARD for 5150/5160, OR JDRIVE, OR VISTA, or other afternarket controller for your 8" needs! BUT, 8"SSSD CAN be done with a slightly modified 5150/5160 controller. The early 8" controllers from Flagstaff Engineering were 5150/5160 stock controllers that they did some cutting and jumpering to. Doctor Marty (Martin Goodman, MD of Coc fame) reverse engineered the Flagstaff mods! Before one of the rushed moves, I had a boxfull of them. I think that that might have been in the stuff that Sellam picked up from my office. To reiterate, if you want to do lots of 8" OR HD 3.5", you are better off with 5170. But the 5150/5160 is pleasant and easier to work with for anything DD, including what you call "quad". -- Grumpy Ol' Fred cisin at xenosoft.com