layers vs SunView (Really: BRL environments)

[Doug Gwyn]

In article <393 at fig.bbn.com> rsalz at bbn.com (Rich Salz) writes:
>This is really funny, no?  BRL wrote their own DMD package because it
>wouldn't run in the BSD world.  Now they're glad because there will be
>a BSD distirbution for the 630, but BRL will be writing their own because
>they prefer SystemV.

It would be nice if you would understand the situation before
making (inane) comments.

The DMD host software licensed by AT&T around 1984 required the
addition of an "xt" pseudo-device driver to one's UNIX kernel.
Unfortunately, as you should know, the internal details for how
this is done vary radically between UNIX System V (the system
AT&T provided a driver for) and 4BSD.  This necessitated the
development of an alternative approach to providing the host
process multiplexer/packet protocol manager.  The only portion
of the AT&T DMD software that was "written" as opposed to
"ported" was this multiplexer process.  The result is usable
from either the native BSD environment or the System V
(emulated) environment, but since I do all software development
in a System V environment (even on 4BSD kernels), the BRL DMD
programming support was set up for the System V environment.

In the case of the "Teletype 4.2BSD tape" that eventually
became available for the DMD, and for the similar 630 host
software package for 4.3BSD that is being made available,
they chose to tailor the programming support for use with
the native (4BSD) environment.  Since this does not meet our
local needs, it obviously will have to be redone.

In any case, unless vismon, sam, etc. come with the AT&T
630 tape for 4BSD, we would have to provide them anyway.

By the way, not all of BRL "prefers System V", just a subset
of us, and only in certain ways (for example, it provides a
much more useful C library).  Generally the local technical
"gurus" seem to prefer the 4BSD environment, and those
producing production applications tend toward the System V
one, but the choice is a complex matter (which may become
unnecessary if the Sun/AT&T deal works out well).