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From: thad@cup.portal.com (Thad P Floryan)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: 3B1 hardware questions
Message-ID: <37394@cup.portal.com>
Date: 30 Dec 90 14:55:59 GMT
References: <4646@amc-gw.amc.com>
Organization: The Portal System (TM)
Lines: 60

jwbirdsa@amc-gw.amc.com (James Birdsall) in <4646@amc-gw.amc.com> writes:

	1) I recently went to add a power switch to my 3B1 monitor. However,
	[...]

I should have some more info re: the "stock" monitor and possible replacements
during the upcoming week.

	2) I have a combo board without RAM. Judging by the number and layout
	of the sockets, it takes 256Kx1 DIP DRAMs, 8 + 1 parity. What speed
	should these chips be? Or am I on the wrong track?

150nS chips work just fine.  In this area (Silicon Valley) at places like
Fry's electronics, "today's" price (in the San Jose Mercury News) for 256Kx1
new chips are:

	100nS	@ $1.29
	 80nS	@ $1.39
	 70nS	@ $1.49
	 60nS	@ $1.95

	If you want to call them (they DO take phone orders w/ VISA and MC),
	their numbers are:

		Fremont CA;   440 Mission Ct,; 415/770-FRYS
		Palo Alto CA; 340 Portage Dr.; 415/496-6000
		Sunnyvale CA; 1177 Kern Ave.;  408/733-1770

	Their prices on 3M DC600A tapes is $21.99 (for 3B2 and 3B1 tape drives)

Cannot even FIND the 150nS any more, but who cares with the prices like those
above! :-)  I've been using the Samsung 80nS in my 3B1 systems.

	3) One of the things I keep hearing from the 3B1 hackers on this group
	is that the machine is fast. I have not meddled with the ktune
	parameters and, in the default state, my old PC/XT is at least as fast
	and faster in some cases. Is something grossly misadjusted or am I
	expecting too much?

Depends on how much RAM and what hard disk(s) you have in your system, and
what you're doing.  A 512K RAM with 10MB 65mS HD system is pitiful, yet that
was the stock configuration when the UNIXPC was first released.  If you have
a system with 2-4MB and < 26mS large-capacity HDs, then the system screams;
my own tests show it outperforming Mac II/AUX 2.0 systems (and the reason is
simple: the UNIXPC has a proper bus structure and has DMA and chips to support
expansion goodies whereas the Macs do not (it wasn't until the Max IIfx that
Apple finally added one DMA chip for the SCSI bus (using a 6502))).

Even then, you have to realize that a dedicated one-task system such as an XT
"may" seem faster in certain circumstances (until you run the UNIXPC in a
stand-alone mode, that is! :-) Do a "ps -ef" on your UNIXPC and see how many
things ARE "running" simultaneously, and consider that you can be doing file
transfers, compiles, edits, games, etc. ALL at the "same" time on the UNIXPC
whereas you'd never be able to do that on an XT.  I often have compiles in the
background during uucp transfers while playing klondike, mahjongg or rocks
"online."

Note also I haven't altered the ktune params from their defaults.

Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]