[HECnet] This is probably been asked already but....

[Johnny Billquist]

On 2012-07-02 16:21, Bob Armstrong wrote:
One of the goals of 11M was to get something that could run on a really
small PDP-11 without an MMU, which 11M can.

    M can run without an MMU??   RSX-11S can, but I don't think 11M can.

It can. It's called an "unmapped" system. That's when you really need to start playing with all those values after partition names... Both at the MCR level, and the TKB level.

    OK, 11S is just a stripped down 11M, but it was still a separate product.
Can you actually gen an unmapped system with a 11M distribution?

Yes.
And -11S is stripped down rather seriously. There are no file systems in -11S. -11S is basically a memory only thing. (Perfect for net bootable systems, btw...)

    Also, 11S could run without any kind of disk or mass storage (e.g. a
complete 11S image could be downloaded via MOP) but I don't think 11M ever
could.

Correct. In fact, -11S never have any file system. You can always have the disk devices, but they are without structure.
-11M is disk based, always. Mapped or unmapped.

    RSX-11S was the "embedded system OS" of the PDP-11 world (at least as far
as DEC's offerings went).

Yep.

    In an unrelated question - was RSX-20F (the CFE for the KL10) based on
11S?   In ran on an unmapped 11/40, so I assume it must have been.

It's actually more or less an unmapped -11M. Same reason. No disks in -11S. RSX-20F is using the shared RP06 as storage.

	Johnny