Date   : Sun, 12 Oct 1980100:22:00-MDT
From   : Frank J. Wancho <FJW@MIT-MC>
Subject: Sector Interleaving and other things

I visited a firm on Thursday that is heavily into using NorthStar
machines as a base for their product: a multi-user machine.  I
discovered that their OS lets you run whatever you want, such as CP/M,
but you must convert to their file format.  One of the changes
required in being able to run CP/M in that system is to change CP/M's
sector interleaving back to sequential!  Why, I asked.  Because it is
faster, I was told.  Apparently the newer disk controllers that have
come on the market since CP/M was first written take up the slack.
N*'s DOS in fact uses sequential sectors and so does the N* version of
UCSD's Pascal.

Has anyone played with CP/M BDOS from this angle and have any facts
and figures to back up either position?  I plan to try it out in a few
days myself and see what happens with my six minute assembly (which is
heavily I/O bound - it seems).

Meanwhile CP/M-86 is well on the way since it has been announced.
MP/M and CP/Net were somewhat premature in release (that's a rumor).
It still bothers me that software is released to let the users debug
it, but that must be a fact of life...

You CAN BUY the source for CP/M 1.4 from Digital Research at some
"reasonable" price.  You can also BUY the source for 2.2, but you must
be an OEM, and pay $5K for the priviledge ($10K for MP/M 1.1).

Indeed, parts of 1.4 was written in PL/M, but I am told that all of
2.0 and up is in assembler...

--Frank