SET CLOCK FAST & 785/4.3 tod clock

SET CLOCK FAST & 785/4.3 tod clock

Post by Bart Mass » Thu, 02 Aug 1990 17:48:00



We tried using SET CLOCK FAST to bump the cpu clock speed on our
VAX 11/785 running 4.3BSD/NFS from Mt. Xinu.  Everything seems
to work great -- no crashes, and the system is much faster, *except*...

The time-of-day clock gains about 1.5min/hr .  My browse through our
kernel sources didn't suggest any obvious reasons for this, and I can't
think of any offhand -- isn't the tod clock supposed to be generated by
a hardware interrupt independent of the CPU?    What am I missing?  What
can we do to fix this?

                                        Bart Massey
                                        ..tektronix!reed!bart

 
 
 

SET CLOCK FAST & 785/4.3 tod clock

Post by ch.. » Thu, 02 Aug 1990 03:48:00


SET CLOCK FAST is intended to run the machine `on the edge', to shake
out hardware bugs faster.  You are not supposed to do normal operations
this way.  If you really insist, though, you can have timed keep
adjusting the clock back, if you have another machine with a more
reliable clock.
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)


 
 
 

SET CLOCK FAST & 785/4.3 tod clock

Post by maxw.. » Thu, 02 Aug 1990 09:32:00



> We tried using SET CLOCK FAST to bump the cpu clock speed on our
> VAX 11/785 running 4.3BSD/NFS from Mt. Xinu.  Everything seems
> to work great -- no crashes, and the system is much faster, *except*...

When I took the VAX-780 hardware courses, the SET CLOCK FAST and SET
CLOCK SLOW options were used for hardware test purposes only. The options
were to be used during diagnostics to help determine if problems were due
to timing problems in the hardware devices. If I remember correctly, the
T-O-D clock is dependent on the same oscillator as the CPU, and the
SET CLOCK options change the frequency on that oscillator.
Don't flame me if I am wrong in this case, I have never worked on the
785, and it has been 5 years since my 780 training took place and 3 years
since I worked on the hardware.

Bob Maxwell             ablnc!maxwell
AT&T DP&CT
Maitland, FL

 
 
 

SET CLOCK FAST & 785/4.3 tod clock

Post by r.. » Thu, 02 Aug 1990 12:27:00


Most UNIX's (VAX implementations included) don't consult the time of day
(time of year) clock other than to set the internal clock.  The time in
UNIX is incremented when a certain number of clock interrupts have gone
off.

-Ron

 
 
 

1. Setting my hardware clock to atomic clock?



by the way, in man hwclock it says

       To see if it is on or off, use the command adjtimex --print and
       look at the value of "status".  If the "64" bit of this number
       (expressed in binary) equal to 0, 11 minute mode is on.
       Otherwise, it is off.

and I do
$ /sbin/adjtimex -p
[...]     status: 64
which makes me wonder what the English of the man page is trying to
say.  Does "status:64" mean the 11 minute thing is on or off?

by the way, the The Clock Mini-HOWTO looked promising, but
seemed not to tell us dummies exactly what to do simplewise.

I installed the ntp rpm from the 2nd mandrake 7.2 CD
and notices that it doesn't put its man pages on the system, but one can dig
them
out of its 'doc' directory... as seen in rpm -ql ntp
--
www.geocities.com/jidanni E-mail: restore ".com."  ?n|
Tel:+886-4-5854780; starting in year 2001: +886-4-25854780

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