[Leica] Re: M9 (Osborne sub-thread)

[abridge at gmail.com (Adam Bridge)]

I wasn't aware that there was any code-base similarities between
CP/M-80 (86??) and MS-DOS.

By "monitor" do you mean operating system? RT-11, the DEC OS most
closely approximated by CP/M, was/is a full operating system that at
that time ran on the full range of PDP-11 machines, from the random
logic original PDP-11 to the PDP-11/60 with it's programmable
instruction set. True, you could elect to completely blow RT-11 out of
RAM is you wanted (many of us considered this a feature for certain
applications), but it also ran in a VERY small memory footprint - I
remember about 4K for the base version. You could also elect to
customize RT-11 and completely reconfigure it's capabilities and
memory footprint. A VERY slick piece of software. It was a fabulous
real-time operating system in every meaning of the word. That a
variant of RT-11 wasn't used in DEC's foray into personal computing,
using, instead the resource hog that was RSX-11/M+, is another piece
of idiocy to lay at the door of Ken Olsen who could conceive of the
minicomputer but who couldn't image how the personal computer would be
used even when he saw it.  He decision is worthy of being in the same
class as Bush's Iraq invasion - but worse.

Adam

On 9/1/07, Jeff Moore <jbm@jbm.org> wrote:

>
> Uh, no.  CP/M, an OS for 8-bit microprocessors with strong interface
> similarities to some of the simpler DEC monitors for the PDP-11
> minicomputers, dates back at least as far as 1974, and was being
> commercialized by 1977.  MS-DOS is derived from CP/M-80.
>