Running X windows on a 16MHz 386sx

[Tin Le]

> In article <1990Oct16.201137.18397 at nstar.uucp> larry at nstar.uucp (Larry Snyder) writes:
>kaleb at thyme.jpl.nasa.gov (Kaleb Keithley	) writes:
>
>>real bottleneck tho' is the VGA display on the 8mhz AT bus.  After a year of 
>>living with the SX, I just upgraded to a 486 and, while all around faster,
>>the display is still the weak link (it is a 16bit VGA.)  What intrigues me 
>>the most is that the display performance for OS/2 is orders of magnitude
>>better; the X server writers need to get a lot smarter about handling the
>>VGA, especially bit blitting.
>
>I've also heard that X11R4 is faster writing than X11R3 with regular
>16 bit VGA boards as well..

   Yes.  X11R4 is faster in many aspects.  The server has been optimized
in a number of areas.  It is well worth upgrading to it if you are running
R3 now.  On an SX, the minimum requirements are (in order):  >=8MB RAM, high
speed graphics card (VGA 800x600 or better), X11R4.

   I use a 386/20 and X11R4 performance is adequate for my need.  I only need
to keep an eye on szebra (a Pub *NIX node with full news feed).  Several
x clients, a TB+ line, news feed, a couple windows all works just fine.  I
do have the system params tuned so that there is no paging/swapping.  No,
I only have 8MB (nothing fancy).  Folks, it is possible to have a usable
X system without spending a lot of money.

    Yes, you are right.  I wouldn't want to also develop software on it.
If I were to do that, then I'd get more memory (at least 16MB total) and
a faster hard disk.  The key point here is not the speed of the processor,
but rather the I/O subsystem throughput.  A 386sx is perfectly adequate to
run X11R4.  The bottleneck that people are complaining about here is the
graphics (EGA/VGA isn't exactly a speed demon, even a 16bit card), paging
and swapping problems (more memory and faster hard disk/controller helps),
and probably also bad serial I/O throughput (the default 8250 or even
14450 UART is a piece of garbage folks, upgrade to 16550 immediately!).

   With the proper system tuning and I/O subsystems, I can make a lowly
386 seems as fast as a SPARC (NOTE: I said "seems") in terms of responsive
user interface.

   I am sure everyone would love to own a 486/33 with 16MB RAM or more.
Yeah, me too :)....  But I sure as hell can't justify spending so much
money when it's not really needed.

In Summary:  Here is my opinion, it's free so take it with a grain of salt.

	A 386sx is fine to run *nix and X Windows

	BUT, it must be at least of the following configuration:

		- 8MB RAM (or more)

		- 16bit VGA (get a fast one) must support at least
		800x600 16 colors (SVGA of 1024x768 is great)

			Or (if you can afford it)

			- 8514/A with a graphic co-proc (TI 32XXX)

		- 14" monitor (16" would be much better); color would
		be nice but monochrome is fine

		- high speed HD system (ESDI or SCSI) it's your personal
		bias here (I prefer SCSI, but 15Mb ESDI is fine).

		- fast HD (of course, fast ctrlr with slow HD is useless)

	Cost:

		386sx/16 Motherboard (0K)		$300
		8MB RAM (100ns or 120ns)		$400-$450
		16bit VGA (256KB VRAM or more)		$180-$280
		14" monochrome (NEC)			$200+
		Adaptec 1542B SCSI			$300+
		80MB SCSI (16ms)			$400+
		case/power/floppy/keybrd		$300
						       --------
						     $2080-$2380

		Unix S5 R3.2 Full package (ESIX?)	$800+
		Thomas Roelle X11R4 Xvga		Free
		Gnu gcc/g++/bash/files/etc		Free

-- Tin Le

-- 
+-----------------------------------------------------------------
|Tin Le           | tin at smsc.sony.com or tin at szebra.uucp
|Station Zebra    |....!{claris,zorch}!szebra!tin
|Sunnyvale, CA    | (408) 739-1520  24hrs Telebit+ 300-19200bps