[comp.sys.dec] VAX 9000 - clock speed.

estey@soleil.sps.mot.com (Bob Estey) (04/13/91)

SUBJECT: VAX 9000 - clock speed.

I was in a meeting and the subject of increasing the clock speed of a VAX 9000
was brought up.  

The person said there was an undocumented feature that would enable me to
log on the console and increase or decrease the clock.  DEC however doesn't 
want anyone to raise it due to system sometimes crashing because the 
appropriate components are not on the system.

Is there anyone out there that can give me anymore information on this.

don@zl2tnm.gp.co.nz (Don Stokes) (04/13/91)

estey@soleil.sps.mot.com (Bob Estey) writes:

> SUBJECT: VAX 9000 - clock speed.
> 
> I was in a meeting and the subject of increasing the clock speed of a VAX 900
> was brought up.  
> 
> The person said there was an undocumented feature that would enable me to
> log on the console and increase or decrease the clock.  DEC however doesn't 
> want anyone to raise it due to system sometimes crashing because the 
> appropriate components are not on the system.

I don't drive a 9000 <envy>, but...

One of the tests on the larger 8000-series VAXes is to wind the clock
rate up to detect marginal components; I assume the 9000 has a similar
feature (along with the ability to screw around with the power
supplies).

The guts is that while the clock rate can be altered from software, the
machine is intended to run at a fixed rate -- winding it up is taking
the brute's components out of their rated specification, with all the
risks that entails.  Unless you are sure of whether it can handle the
higher clock rate, I'd say leave it alone.

Don Stokes, ZL2TNM  /  /                             don@zl2tnm.gp.co.nz (home)
Systems Programmer /GP/ GP PRINT LIMITED  Wellington,       don@gp.co.nz (work)
__________________/  / ----------------   New_Zealand__________________________