From: jmfbahciv on
In article <doc7235eie7g0pmhrvvq1eu4kqp8fa6qu1(a)>,
David Powell <ddotpowell(a)> wrote:
>In article <5jp6f4-d3b.ln1(a)>,
> Terje Mathisen <terje.mathisen(a)> in
>alt.folklore.computers wrote:
>>Eric Smith wrote:
>>> nmm1(a) (Nick Maclaren) writes:
>>>> I know quite a few people who used Z80s for that, and they
>>>> never really cut the mustard for mission-critical tasks
>>> I saw quite a few Z80s used for mission-critical critical tasks.
>>Back in 1981 we had 12 (or 16?) channel 'Acoustic Emission' gear using a
>>dedicated Z80 per channel, this was used for monitoring stuff like
>>building platforms, offshore oil rigs and other relatively
>>'mission-critical' applications.
>We had both, 11/23 with a few 4 channel async cards as data
>concentrators / protocol convertors to multiple Z80s as embedded
>real-time controllers. Not much difference in hardware reliability
>after infant mortality, provided appropriate PSUs and fans. Most of
>the early Z80 failures were PSU, charge-pumps from the +5 for the
>RS232 drivers that slowly declined from 10V ish to not much over a
>couple of years. Software reliability for the 11steadily improved
>over the years, easy to investigate post-mortem, and add robustness
>where necessary. The Z80s were just replaced, usually without
>>> More Z80s have been used for LIFE-critical tasks than the total
>>> number of PDP-11 computers manufactured.
>>Almost certainly true.
>Not surprising, after about 1979, every DEC sales office had painted
>on the wall. "Thirty-two bits good, sixteen bits bad."

And 36 was punishable by death.