DEC KM11 (Was: DEC KL11)

Phil Budne phil at
Thu Sep 23 21:22:48 CDT 2021

> 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
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!

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