hxn8477%njitx.decnet@njitc.njit.edu (NJITX::HXN8477) (11/25/88)
I know this is a stupid question, but I'll ask it any way because I am
VERY new to unix. As far as I know, there are 3 flavors of unix: BSD
which is public domain, System V which is moderately priced and Xenix
which is astronomically expensive. Just what is the difference between
the 3 flavors. And if all of them can run any unix program, what makes
one buy Xenix, when they can get BSD?
+---------------------------+------------------------------------------------+
|Hamed Nassar |Internet : hxn8477%njitx.decnet@njitc.njit.edu |
|EE Department |UUCP : bellcore!argus!mars!nancy |
|NJ Institute of Technology |CompuServe: 74000,130 |
+---------------------------+------------------------------------------------+
------guy@auspex.UUCP (Guy Harris) (11/26/88)
>As far as I know, there are 3 flavors of unix: BSD which is public >domain, System V which is moderately priced and Xenix which is >astronomically expensive. Incorrect. There are several flavors, almost *all* of which are derived from AT&T code and thus not public domain. The three flavors you list are all derived from AT&T code, and thus none are public domain. >Just what is the difference between the 3 flavors. There are several differences. BSD is derived from an earlier VAX version called 32V, which is pretty much a PDP-11 version called V7 ported to the VAX. It has picked up some features from later UNIX versions. 4BSD supports demand paging on machines that have it; it prefers a "large" machine (with 32-bit "int"s, for example, and with support for demand paging), although it has allegedly been ported, or is in the process of being ported, to some set of 80286-based machines. In 4.2BSD and later releases, it comes standard with support for TCP/IP networking. System V is derived indirectly from V7 as well. It is also derived from an earlier PDP-11 version called PWB/UNIX. It has picked up some features from 4BSD. Later versions support demand paging, but those later versions prefer a "large" machine as well. As distributed by AT&T, it does not come standard with TCP/IP support; the latest versions have a framework called STREAMS into which said support can be dropped, and various people have basically ported various 4.xBSD versions of TCP/IP into that framework. Xenix is, I think, derived from V7 in its earlier incarnations, from V7 and System III (which is basically a S5 predecessor) in later incarnations, and, I think, V7 and S5 in its most recent incarnations. I don't think TCP/IP comes standard with Xenix from Microsoft; I don't know which Xenix versions support it. >And if all of them can run any unix program, what makes one buy Xenix, >when they can get BSD? 1) Not all of them can run any UNIX program. No feature set of those versions is entirely a subset of the feature set of some other version. 2) You can't get BSD for every machine in existence; the same applies to vanilla System V as distributed by AT&T and to Xenix.
gwyn@smoke.BRL.MIL (Doug Gwyn ) (11/26/88)
In article <17641@adm.BRL.MIL> hxn8477%njitx.decnet@njitc.njit.edu (NJITX::HXN8477) writes: >I know this is a stupid question, but I'll ask it any way because I am >VERY new to unix. As far as I know, there are 3 flavors of unix: BSD >which is public domain, System V which is moderately priced and Xenix >which is astronomically expensive. Just what is the difference between >the 3 flavors. And if all of them can run any unix program, what makes >one buy Xenix, when they can get BSD? UNIX is a trademark of AT&T. All three variants you mention, and several others available from a variety of vendors, are derived from AT&T-owned source code and are distributed under license from AT&T. Xenix is the trademark for MicroSoft's version, BSD stands for "Berkeley Software Distribution" and is available in source form to UNIX System source licensees only (version 32V or later) for a moderate fee from the University of California at Berkeley, and UNIX System V is AT&T's name for their commercial versions of the UNIX operating system. Currently source licensing seems to be available only for UNIX System V Release 3 and costs something like $65,000 (may be higher) for commercial use. Binary releases of UNIX are prepared by vendors working under explicit sublicensing agreements with AT&T. AT&T's binary sublicensing fees are sufficiently low that end-user prices for a binary UNIX can be on the order of a couple of hundred dollars or less. Binary distributions, until recently, need not conform to any particular standards and so many different variations are provided under the name "UNIX". UNIX is emphatically NOT in the public domain. It is AT&T property and is protected primarily by "trade secret" provisions. Enhancements made by third parties are generally their property. There are a few UNIX "work-alike" systems commercially available that are not derived from AT&T source code. Availability of these is of course controlled by their owners on their own terms. Generally, different versions of UNIX offer different features, or the same features provided in different (often incompatible) ways, so true binary program portability is not attained. Source code can be designed to successfully compile and link on a wide variety of UNIX variants, and recent efforts at standardization (notably IEEE Std 1003.1-1988 and the forthcoming ANSI C Std X3.159-1989) should help improve the situation. AT&T also as of UNIX System V Release 3.2 had merged Xenix and UNIX System V into a single version, to henceforth be marketed under the UNIX System V banner, and have a current effort to merge SunOS (which is based on 4.2BSD) and UNIX System V into UNIX System V Release 4.0, at which point the features of the major UNIX variants will all have been combined in a single AT&T UNIX System V product. AT&T has also been pushing for binary standards (on a per CPU family basis) to allow future successful marketing of "shrink-wrapped" software for UNIX-based systems (without the customer having to worry about variants of UNIX). However, IBM has been pushing their own variant, AIX, which was adopted by the so-called Open Software Foundation, and DEC's Ultrix seems to be continuing its own separate evolutionary path. Probably other vendors will maintain their own weird flavors of UNIX into the foreseeable future. This clearly cripples the whole UNIX binary software market, but what does one expect, given the short-sightedness of the MBAs typically in charge of marketing? The academic/research world also seems to be pursuing their own UNIX evolutionary directions via 4.4BSD, MACH, 9th Edition UNIX, etc. I have no complaint against this, after all it IS research; but some commercial vendors are likely to try to track the research directions in their commercial products, which would also increase fragmentation in the marketplace. If this sounds like a mess, it is.
ado@elsie.UUCP (Arthur David Olson) (11/26/88)
In article <8980@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn ) writes: > UNIX is a trademark of AT&T. UNIX is a registered trademark of AT&T. (And when is BRL going to get rid of the extra space in front of the right parenthesis, anyway? ) -- Arthur David Olson ado@ncifcrf.gov ADO is a trademark of Ampex.
gwyn@smoke.BRL.MIL (Doug Gwyn ) (11/27/88)
In article <8516@elsie.UUCP> ado@elsie.UUCP (Arthur David Olson) writes: >In article <8980@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn ) writes: >> UNIX is a trademark of AT&T. >UNIX is a registered trademark of AT&T. It's that, too. Is it also Marca Registrada? >(And when is BRL going to get rid of the extra space in front of the >right parenthesis, anyway? ) Probably whenever we install news software that does it right. I assure you we didn't write this software.