MJB@cup.portal.com (Martin J Brown-Jr) (01/17/89)
I recently acquired a 20mhz/386, with 2megs memory and 43meg Priam. I believe
UNIX/XENIX/VPix or something will be needed in the near future. I will want to
use X-windows and eventually add 1 or 2 terminals.
I have a few questions about such a setup, and I realize that they've been
asked before, but I could not find an archived collection geared specifically
to them.
1) How much memory is needed for a unix-pc system in a minimal unix
configuration? an adequate configuration? good configuration?
2) Same thing for a harddisk?
3) When the 386 acts as system unit/console to 1 or 2 terminals, can
it still be used to do non-administrative tasks (do word processing
etc.)? is there significant system degradation in speed (more than
say an additional terminal would decay system speed)?
I've been using an Amiga with 2.5megs for years, and I've been disappointe
by the speed of Windows/386 v2.1 by comparison. Since I haven't spent alot of
resources (time and money) at this point on MS-DOS/386 yet, i thought now
would be a good time to look at the alternatives.
Any comments, advice, or opinions would be appreciated? Thanx for your hel
- MJB -jcm@mtunb.ATT.COM (was-John McMillan) (01/18/89)
In article <13630@cup.portal.com> MJB@cup.portal.com (Martin J Brown-Jr) writes: >I recently acquired a 20mhz/386, with 2megs memory and 43meg Priam. I believe >UNIX/XENIX/VPix or something will be needed in the near future. I will want to >use X-windows and eventually add 1 or 2 terminals. ** To the best of my troubled knowledge, YOU HAVE MIS-POSTED your ** question: this group is for the UNIX[rg]-pc aka 3B1 aka 7300 aka S4. ** However, in the spirit of "I'm replying to you anyway" and "Gee it's ** fun to invite endless opinions from everyone with an opinion:" ************************************************************************* ***** NOTE: THE FOLLOWING RELATES to 386 machines running UNIX SVR3 ***** ************************************************************************* > 1) How much memory is needed for a unix-pc system in a minimal unix > configuration? an adequate configuration? good configuration? You haven't permuted your conflicting interests into this: N-users, M-memory intensive applications simultaneously, u.s.w. Loose answer: 2 MB, 4-6 MB, 4-8 MB. Kernels consume ~.5 MB TEXT + .5->1.5 MB DATA depending on TUNABLE parameters. (You in the background -- SHUTUP! I have perhaps MORE drivers/TEXT than many systems -- less than some.) 2 MB: A small-tuned kernel chews up about 1 MB for the kernel and 1 MB of user-RAM leaves a single user doing a modest amount of paging for a small collection of modest programs. 4 MB: Larger programs push up the PAGING (yetch) and a single user running COMPILES and other piggies should have MORE BUFFERS (a larger kernel). To support the kernel and to reduce paging, 4 MB is needed. For any serious use with several users or large programs, 4 MB is the starting point. 6+ MB: Multiple heavy users may require 6 MB... but my benchmarking suggests it's NOT worth EXCEEDING 6 MB until the need is demonstrated. In fact, I'd start with 4 MB and measure paging before moving to 6 MB. > 2) Same thing for a harddisk? 40 MB -- 40 MB drives barely hold the system software for standard systems. Add windowing pigs and your outta the game. Add development sources and your outta space again. And many ~40 MB drives are SLOW -- which particularly hurts PAGING throughput. ~65 MB -- Barely better than 40 MB -- you'll FILL it faster than you'd think! ~135 MB ESDI drives -- These more often have the SPEED to support better paging and random accesses. Look for < 20 ms access times. And you've bought some SPACE for a change. >I< consider these a STARTING POINT for a professional system. > 3) When the 386 acts as system unit/console to 1 or 2 terminals, can > it still be used to do non-administrative tasks (do word processing > etc.)? is there significant system degradation in speed (more than > say an additional terminal would decay system speed)? There is NO appreciable amount of KERNEL-DRIVEN messaging to the console: only messages of the "MY GOD I'M CRASHING" type go directly to the console in a system-locking mode. On 386 systems, most character-to-console (non- X-windows) ASCII-to-bitmap translation is done on the interface board [any corrections out there from longer-term 386 users?] In THIS mode, there is negligible CPU impact, [unlike on the UNIX-pc]. The only peculiarities of the console occur when you drive it in a bit-graphics mode and the load here is no different from driving any other terminal through an identical interface. ERGO: X-windows may eat up your CPU unless you are running the window on some graphics-engine that off-loads the system-CPU whether-or-not the console's the target. > I've been using an Amiga with 2.5megs for years, and I've been disappointed >by the speed of Windows/386 v2.1 by comparison. Since I haven't spent alot of >resources (time and money) at this point on MS-DOS/386 yet, i thought now >would be a good time to look at the alternatives. UNIX is a "general purpose OS". It CANNOT be as fast as a special-purpose system with limited multi-tasking/multi-user support. Windowing is a case where the generality of the interface EATS your CPU alive. Things are improving, in some degree, as experience is gained. But more generalizing is also being added at the same time: if SPEED is of the essence, single user systems SHOULD always be far ahead, and often specialized terminals are the next best step, as they may be able to unload the system CPU -- for a PRICE! O boy... what a drawn out and flame-provoking reply for a mis-posted question. Think I'll sleep in the NOMEX tonight. And in my prayers, I'll ask that folks E-mail their opinions to the original poster, /dev/null, or [sigh] me... jc mcmillan -- att!mtunb!jcm -- sorry, just mumbling. [Spkng for SELF only]