2 Feb
2017
2 Feb
'17
10 p.m.
On Feb 2, 2017, at 10:06 PM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
,,,,,,
The advent of the /23 (with no CSW, and no KW11-L/P), made things more
complicated. (The clock is pretty key - Unix needs one - several things,
e.g. parts of the teletype drivers, require real-time delays provided by the
clock. I've never tried to run Unix without a working clock, I'm not sure if
it would run without slowly grinding to a halt as stuff waited for clocks
delays that never happened.(
Of course many preemptive OS?es use clock or other interrupts to drive their task
schedulers.
I recall a situation in which the LTC was buggy or someone just switched it off.
The OS didn?t crash, but its responsiveness was rather odd. Disk and perhaps some
terminal IO kept the scheduler going. With many users we barely noticed a difference,
but when there were only 1 or 2 users, it just kind of crept slowly along. Someone
finally
noticed the timestamps on files never changed.
Jerry
jsw at ieee.org