hadji@dasys1.UUCP (Toby A David) (10/07/89)
Hello World
I would very much appreciate opinions/reports on 20 or 25 mhz 386
motherboards. Micronics in particular.
The box I'm putting together will be mostly used for SCO Xenix286 and
eventually Unix 386. I intend to add 4 meg of ram.
The following questions come up..
1. Advantages to the 25mhz with cache memory board?
2. 100ns ram, or do you prefer the 80ns ?
3. Any problems with the memory interleave?
4. Optimum bus speed & wait states for the above operating systems?
5. Any problems with any particular MFM or ESDI controllers/drives ?
to the 25mhz (cache memory)
Any Email/Post opinions would be welcome. Thanks in advance.
--
Toby A David
Big Electric Cat Public UNIX
..!cmcl2!{ccnysci,cucard,hombre}!dasys1!hadjicaf@omen.UUCP (Chuck Forsberg) (10/09/89)
I picked up a 33 mHz Micronics motherboard and 8 MB worth of RAM chips not long ago (price ~ $3000). News stories of difficulties with the 486 provided impetus for this decision. The Micronics 33 mHz is rather fast. How fast depends on what you do. I made a modified siev.c with 200000 byte array, compiled huge model. This program runs in 24 seconds on the Micronics, 66 seconds on an early 18 mHz Intel motherboard. The large array was used to prevent the cache from attaining a 100 per cent hit rate which is not typical of normal Unix operations. I've run SCO Unix 3.2 on the Micronics for a short time. It really bangs the disks! Unfortunately, the Micronics has a choice of 11 and 8 mHz I/O bus speeds, and not all cards can keep up with that. I've now replaced the AST serial card on the SCO system, and will put that back on the Micronics as soon as I get the right size tower box to hold all the junk I use on that system. In the meantime the Micronics is fat and happy running ISC 2.01. The difference in speed on ISC is not as visceral. But then the WrenII that runs ISC doesn't make any noise when seeking... I would mention some disadvantages to the Micronics that may or may not affect you. It is too fast for some cards. Some other motherboards are more forgiving. Micronics does not have resident serial or parallel ports, which may cost you a board slot or two. The memory board takes up a board slot; with the piggyback (for 16 MB) it *might* take up two. Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ Omen Technology Inc "The High Reliability Software" 17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406 TeleGodzilla:621-3746 FAX:621-3735 CIS:70007,2304 Genie:CAF