ard at p850ug1.demon.co.uk
Tue Nov 16 15:33:37 CST 2010
> Tony writes:
> > Tim writes:
> >> Having worked with 1103's I would argue that by modern standards
> >> Even the "cream of the crop" were little above floor sweepings.
> > Was it that a lot of new 1103s were DOA, oe what there a problem with=20
> > them fialing in use, or what?
> > The reason I ask is that I have several old HP calculators full of 1103s,=
> > and AFAIK all are original (and gettign on for 40 years old). So far,=20
> > otuch wood, I've not had any problems with the RAM in these machines.
> How many hundreds of 1103's are in each HP calculator? :-)
It depends on the model. I think my 9830 has 0.96 hundreds of 1103s, for
example. And that';s not fully populated.
> In the early minicomputer 1103-based memories (say 16Kbytes, so
> 128 1103 chips) it was, um, optimistic to expect a lot of stability.
that is the sort of size of the HP9830 memory. Problems in this area are
not at all common.
> I'd expect that smaller systems probably didn't have ECC or scrubbing
> but also didn't have high expected uptime. Were 1103's in the HP 9830?
> I had a couple but they usually worked fine enough that I never had
> to go rummaging through the insides.
Yes, the HP9800 series (9810, 9820, 9830) are the machines I am thinking
of. I beleive the 9810 was one of the first commerical applications of
the 1103. Interestingly, the memory unit in the 9210 and 9820 is its own
module, a metal box cotnaining the RAM boards (nothing but 1103s) the ROM
board(s) (HP custom 512 byte ROMs) and the memory control boards. One
rumour was this was done so that a different memory technology could be
easily fitted if the 1103s had proved unreliable.
The 9830 hasa more conventional layout with all the boards going into one
main backplane at the bottom
The 9810 is probably the only machine where memory expansion involves
multiples of 3 1103s. User programs are stored as sequences of 6 bit
keycodes and there si hardware in the memory controller to store a word
in 2 consequtive memory locations (thus the ssytem 16-bit RAM is 8 chips,
user progam RAM is 3 chips). The 9820 and 9830 spoil the fun hby having
conventioanl 16 vti wide memory in 16 1103s.
> My feeling is that in the 1103 era (which preceded my direct
> involvement but I inherited several 1103-based systems), DRAM chips
> were not quite ready for prime time. By the time the 4116 came
> along things had settled down and a lot had been learned from
> the 1103 and DRAM really was ready for prime time.
Possibly. The 1103 was the first 1K bit DRAM IIRC after all. However, I
wonder how much was due to problems with the DRAMs themselves and how
much was down to problems with supplies (They are unconventional for the
PMOS 1103s, it's really a main -16V supply and a +3V bias supply, often
states as 16V and 19V), decoupling (they are touchy about this!), signal
timing and the like.
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