Subject: Re: Status Vax 4000/60, 400/90, 4000/vlc
To: None <>
From: Michael Kukat <>
List: port-vax
Date: 02/23/2000 23:44:19
Hi !

On Wed, 23 Feb 2000 wrote:
> I'll look up the KA660 stuff when I get the chance but I won't be near any docs
> until monday at the earliest. Typically the console will test out the hardware
> and I would expect it to test the cache. However, I would expect the cahce to
> be turned off so the OS can decide what to do with it.

If you see something about BCACHE, this would be interesting. I just found
some lines about it in the TM, but nothing really usable. No IPR numbers, just
the register names, very vage information.

> BTW: you don't need to write the data lines at all - although it probably does
> not hurt - and if all banks are turned on at once then writing a tag writes it
> to all banks in parallel. No need to do it one bank at a time. In fact the
> manual suggests that you don't do it one bank at a time.

This was for diagnostic purposes, but i think, it's not that bad to check the
8 (TM sais 6, but experiments gave 8) cache blocks.

> One thing that might matter is that you are not actually testing the banks -
> whereas the console does. The manual implies that banks which fail
> manufacturing tests are burnt so that they cannot be turned on. But banks that
> go bad during the life of the chip can still (presumably) be turned on. So
> since the console tests the banks you should not enable any extra banks in your
> code. Leave BEHR alone and just write the tags. 

I do some simple pattern test. Not really secure, but maybe better than just
leaving it alone. Maybe i kick it out somewhen, if i don't find some cool words
to say why i could need this :-)

> >If my VLC wouldn't run that fine under VMS, i would suspect a broken cache in
> >my box. If someone wants to check it out, i could put a kernel with my cache
> >routine somewhere, but i don't expect other results than i have on my box.
> I'll have a closer read of the manuals on Monday and see if there is something
> obvious I've missed.

VLC is really interesting. The differences in PCACHE init from 660 to 48 are


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