[Coco] How to get time in DW4

Gene Heskett gheskett at wdtv.com
Tue Oct 9 10:37:17 EDT 2012


On Tuesday 09 October 2012 10:07:13 Bob Devries did opine:

> ok, I've done some research, but I can't find out how to get the time
> from the DW4 server and put it inot the OS-9 clock. Sure, I can see how
> it could be written, but is there an existing utility to do that?
> 
> I'm using nos9l2v030209coco3_dw.dsk to boot from in my Coco3, and also
> as drive 0 in the DW4 server.
> 
> If I use setime, I get a message "Clock initialization errors". The
> clock is set by default to the time date/time when the distro was
> created; in this case 16 August 2012.
> 
> Regards, Bob Devries
> Dalby, QLD, Australia

I noted that the dw related .dsk's have a clock2_dw3, which I assume sets 
the clock, and maybe even resets it occasionally, from the server running 
on the pc.  But I've not tested it Bob, so I have no clue how it works, or 
even if it works.  Since my TC^3 has a clock chip that seems to keep pretty 
good time, I've not been nagged by the setime call in the startup in close 
to 20 years since the first HD setup I had was a B&B XT-RTC, on a coco2 all 
those years ago.

However, since the clock here is maintained by NTP to within a couple 
milliseconds of NBS time, it might be cute to have a coco clock that 
accurate too.  I'll give it a shot when the current project is finished.

Bear in mind that in some clock2 modules, the access to the RTC clock 
itself is very time critical so the IRQ's are locked out while it goes thru 
the procedure to access the RTC.  The original B&B clock did this, and 
locked out the IRQ's for over 100 milliseconds at the top of the minute.  
This was a death sentence to any attempts to establish a error free comm 
channel for the coco, even thru a 300 baud modem because the data didn't 
stop, so the error recovery had to be done.  The original rz/sz we had, had 
a 1 minute delay to 'let the pipeline drain" before it attempted to restart 
the data flow.  It took me a while to find that, and by the time I was 
done, the B&B clock only did its update from the chip at boot, and once 
daily at midnight.

So people working on clock modules that do assess an rtc chip, need to 
avoid those chips which require a 'password', such as the chip in the B&B-
XTC did.  However, free access can also be a problem, and I'll offer the 
clock in the Disto 4n1 as a prime example as it was very susceptible to 
powerup & powerdown noises screwing up its time.  The clock in the TC^3 has 
been the first rtc I've had that seems 100% immune to these sorts of 
problems.

Cheers, Gene
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