[time-nuts] 60Hz mains clocking in computers

[David I. Emery]

On Sun, Dec 13, 2009 at 07:39:05AM +0000, Poul-Henning Kamp wrote:
> In message <2157.12.6.201.67.1260689371.squirrel at popaccts.quik.com>, "J. Forste
> r" writes:
> 
> >I'm not so sure about the Nova 1200. I think all the Novas had the RTC was
> >on a standard I/O board, [...]
> 
> No, it was an option, but almost everybody bought it, because it was
> necessary to run any kind of timesharing kernel (RTOS, DOMUS, etc)

	Technically one could order basic IO boards without some of the
functionality - they simply didn't stuff in some of the chips (and more
than one customer just added the requisite chips themselves).   I do
remember that there were some functions on that card that were rarely
stuffed...

	I seem to remember that RDOS (the NOVA disk operating system)
DID require the RTC and I certainly don't remember any hacks in the
system code to get around the need for timer interrupts to keep time and
handle delays and timed waits.  It was a real time multitasking kernel,
though only one "process" (mostly) due to the lack of memory management 
Long time ago though...

-- 
  Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."