Yes, that's certainly true, Richard. The 3090 memory was solid state of
some type. I mentioned it because it was the only reliable number for
cost that I could fine.
Have a good one.
DJ
Schuh, Richard wrote:
Yeah, but 3090 memory was not ferrite core, was it? IIRC, it was much
cheaper and more reliable. I wasn't privy to the bean-counting
specifics, but the rumored cost of the LCS storage on our 360 class
machines was in the neighborhood or $2.5-3M per 2MB unit. And they
were real core - you could look through the glass panels and see the
individual planes of wires and doughnuts. The stuff was not reliable,
so we had 3 boxes in order to always have 1 available for the
production ACP system. There was usually 1 in use, 1 being repaired,
and 1 just out of repair that was on standby. The care and feeding of
those animals was a career.
Regards, Richard Schuh
-----Original Message----- From: The IBM z/VM Operating System
[mailto:[EMAIL PROTECTED] Behalf Of Dave Jones Sent:
Sunday, October 08, 2006 7:33 AM To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: Real core
According to some Computer Science class notes from the mid 1990s
found here:
http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fww
w.cs.utexas.edu%2Fusers%2Fdahlin%2FClasses%2FGradArch%2Fnotes%2Flec3.ps&ei=GQcpRaqwKJTowQKozoGZCw&sig=__UYn2qNuRCi6tCHeKT4QmvAKPUsw=&sig2=BLEvr7YHUEbXBBf9FMw5Ug
a megabyte of 3090 memory cost $19,200. That works out to
$0.018311/byte (1 MB = 1024 * 1024 bytes).
DJ
Gabe Goldberg wrote:
Just because I felt like doing the calculations:
Mitre installed VM/370 on a 1/2 megabyte 370/145 (1973), upgraded
to a one megabyte 370/148 (1975 or so). I handled upgrading both
processors' memories: the 145 by 1/4 megabyte, the 148 by a full
(!) megabyte. I vaguely remember that both upgrades cost about
$30,000. It also took a while to evaluate competing vendors; in
both cases we installed non-IBM add-on memory, an interesting
engineering process in itself.
So non-core 145 memory cost $0.11444/byte and 148 memory cost
$0.02861/byte.
Phil Smith III said:
Ok, this is obscure to the max, but: ISTR real core costing
$1/byte. Someone else says: "$1 a byte was extrordinarily cheap for
1971. Ferrite core was going for up to $2 per BIT."
Of course, he then goes on to talk about PDPs, so maybe he's
talking about core made in Maynard instead of Mexico...
Anyway: do any of the other old-timers remember anything about
this?
