Re: Does the KA630 have a TB?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> I don't think it does, not on any specific size.  I think it, that
>> version, just depends on its size and replacement policy being such
>> that that stale entries get replaced before they cause trouble.
> [a 300-octet line - TLDR: "depends" may be too strong]

Possibly.  "Depends on" in the sense of "this is the reason it works at
all in view of the missing invalidations".  It _would_ also be accurate
to call it a masked bug; I wrote from the mindset of "why did this even
kinda-sorta-mostly work on a real KA630?".

Given how tiny the KA630's TB is, I suspect it would be quite hard to
find a realistic workload that failed for lack of invalidations,
probably somewhat difficult to construct a synthetic one either using
this kernel (it probably could be done without too much trouble if you
don't care about even attempting to be a UNIXy OS).

It does occur to me that I think I tried, years ago, to run NetBSD on a
more recent VAX - one of the desktop boxes, I think - and failed.  At
the time I probably wrote it off to hardware issues, but I don't
remember the symptom enough, so it could have been this.

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