Type 270 disk file on PDP-6

From: Eric Smith Sent: Saturday, March 12, 2016 8:52 PM Probably. Kind of. More or less. The disk file is called a 5022. The 270 is the disk file *control*, and yes, it has device code 270, but it attaches to the data control type 136 (device code 200). Other things connecting to the 136 are the microtape control type 551 (device codes 210 and 214) and the magnetic tape control type 516 (device codes 220, 224, and 230). Device codes were assigned sequentially, and the disk file control was not originally part[1] of the PDP-6 system, so it probably just got the next number available. That some wag decided to use that as the type number was more or less likely when it came down the pike. Rich [1] Based on the fact that it was built using Flip Chips, initially invented for the PDP-7, rather than System Modules (either the kind used in the PDP-1, PDP-3,[2] PDP-4, and PDP-5, or the extended kind invented for the PDP-6). [2] Remember that while DEC did not build a PDP-3, a customer rumored to have been a front for the NSA did. DEC sold designs as well as actual hardware in the early days. Rich Alderson Vintage Computing Sr. Systems Engineer Living Computer Museum 2245 1st Avenue S Seattle, WA 98134 mailto:RichA at LivingComputerMuseum.org http://www.LivingComputerMuseum.org/