bart@reed.UUCP (Bart Massey) (08/27/87)
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
chris@mimsy.UUCP (08/28/87)
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) Domain: chris@mimsy.umd.edu Path: seismo!mimsy!chris
maxwell@ablnc.UUCP (08/31/87)
In article <6989@reed.UUCP>, bart@reed.UUCP (Bart Massey) writes: > 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
ron@topaz.rutgers.edu.UUCP (08/31/87)
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