Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn From: gwyn@brl-smoke.ARPA (Doug Gwyn ) Newsgroups: comp.unix.questions Subject: Re: layers vs SunView (Really: BRL environments) Message-ID: <7251@brl-smoke.ARPA> Date: 12 Feb 88 06:18:28 GMT References: <14140@pyramid.pyramid.com> <5400018@snail> <7223@brl-smoke.ARPA> <17930@topaz.rutgers.edu> <7239@brl-smoke.ARPA> <393@fig.bbn.com> Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) ) Organization: Ballistic Research Lab (BRL), APG, MD. Lines: 40 In article <393@fig.bbn.com> rsalz@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).