Tony Duell's maxed out 5160 and PDP

On Sun, 7 Aug 2011, Jeff Jonas wrote: WHICH INCLUDED THE STOCK IBM 5150 FDC. NO. You are thinking of the AT (5170) The 5150 AND the 5160 used a controller card that directly supported 4 floppy drives. (and NO hard disks. THAT was on another card). 2 of the floppies connected to a 34 pin card edge on the FDC board. The other 2 connected to a DC37 connector hanging out the back of the case. With the 5160, there was the addition of a hard^H^H^H^H FIXED disk controller. IBM would not call it a hard disk, because that had negative connotations, particularly with "ease of use". They thought that "FIXED" didn't have negative connotations (except in a veterinary context?) They also called the main circuit board "system" board, rather than "motherboard", s'posedly due to the use of "mother" as a prefix in widely publicized speeches by Black Panthers at Merritt College. The 5160 HD controller (made by Xebec) handled 2 st412 style MFM drives. It was set for 10M drives. That could be changed to 5, 16? and 24? through soldering jumpers in a block in the middle of the board. Further changes could easily be accomplished through editing the ROM, or tellinf the OS to ignore the ROM values in software. What YOU were thinking of was the 5170 controller (WD?) that handled 2 ST412 style MFM drives (one 34pin (2x17) berg and one 20?) and 2 SA450 style floppies (one 34 pin berg). ANYTHING that you write. (debugging mode in XenoCopy often made use of alternate display, and some outputs to a P.O.S.T. card, but MOST of that code was compiled out on release versions. We once tried a release where the HELP screens were ALWAYS activated on alternate display, but the users that NEEDED help wanted handholding instead.) Early Windoze development software supported two videos. I think that some early (pre-megapixel) CAD used both IBM displays.