🚀 go-pugleaf

In article <270480f6@ralf>, Ralf....@B.GP.CS.CMU.EDU writes:
> In article <1990Sep2...@ap.co.umist.ac.uk>, r...@ap.co.umist.ac.uk (bob nutter) wrote:
> }Yeah, apart from the power supply storing charge, those dynamic RAM chips can
> }hold data for a long while too, often a couple of minutes, which is enough to
> 
> A couple of seconds I can believe, but no way minutes....

  In the days of S-100 systems, a company called TDL made 16Kb memory cards
which they named the Z16. These boards used "pseudo-static" (their term, not
mine) RAM chips called SEMI 4200's. These chips were *huge* (physically),
even for their day.

  I had two IMSAI systems, one with disk and one without. Since it was a real
pain to load software from paper tape, I developed the habit of plopping a Z16
into the disk system, loading the program, powering off the system, and moving
the board to the diskless machine. Once installed there, I'd power it on, load
the starting address and hit run. Worked like a champ - and you had up to about
15 minutes to get the board moved over before bit rot set in.

  My theory is that the RAM chips were dynamic, but had built-in refresh cir-
cuitry, and that (being dynamic) they pulled very little power, so the bypass
caps on the board would keep them running for a long time after power was re-
moved.

	Terry Kennedy		Operations Manager, Academic Computing
	terry@spcvxa.bitnet	St. Peter's College, US
	te...@spcvxa.spc.edu	(201) 915-9381