> But the sector format is a different matter. If it's designed for > PDP-11 and friends, presumably it has a 512 byte sector size.
> For PDP-10 or -20 use you'd presumably want a sector size consisting > of some round number of 36 bit words. 576 byte sectors (128 words), IIRC. The unit of allocation on TOPS-20 was a page (512 words). I forget what it was on TOPS-10: 256 word blocks? My notes (from sources unknown) say (of the ML11A): solid-state (ram) disk; 2MB/s xfer 1-31 arrays of 512 or 2048 blocks ea using 11/70 MK11 (MOS) memory looked like RS03/RS04 to s/w http://gunkies.org/wiki/RS03/04_disk_drive says about *REAL* RS03/04 drives: "basic format was 18-bit words (for use in PDP-10 and PDP-15 machines)" But I doubt that anyone would care to replicate THAT feature (throwing away two bits of each word) on a PDP-11 option!