From: radar@grumpy (Reidar J. Husmo) Subject: Re: Cacheing IDE controllers Date: 2 Apr 1993 14:05:52 GMT
-Kevin Smolkowski- (kevins@aragorn.ori.org) wrote:
> I have a Promise DriveCache cacheing disk controller with
> 4 megs of ram on it. It does make a difference in the
> speed of my system. Right now when doing a shutdown
> I sync a couple times and then wait about 15 seconds for
> the controller to flush the cache. Haven't had a problem
> yet.
Hey, I've got one, too. Isn't it nice reading about these people running
into a (virtual) brick wall once a minute/30s when the system syncs?
> 1. Am I just lucky? Should I worry about it?
I wouldn't worry. As soon as you stop writing/reading to the cache, it will
start updating the harddisk. After all, why should it wait 15 secs to do it,
when chances are that you'll write something else then?
Personally, I just 'shutdown -h now', and wait for 'System is halted' before
turning the system off. No problem so far.
> 2. Anyone patch sync or write some sort of flush utility
> to force the card to write all data to disk? The
> controller comes with a msdos utility that does this.
> I suspect that this would be very controller dependent,
> but not that hard to do.
Well, if you're feeling particularly masochistic (and only a sadist
wouldn't provide the following advice to a masochist), do a
'yes>/tmp/foo' before halting the system... This ought to force a
cache flush...
> 4. I didn't post this elsewhere as I suspect that I may be
> in for a bit of linux kernal patching.
If anybody else has got one of these cards and would like to do a bit of
hacking, could you please give me a clue as to how I can turn the thing off?
I'd like to do a performance test under Linux... (I tried it under DOG, and
indeed the system was faster with smartdrv+hardcache than just hard-cache.
Unfortunately it was even _faster_ with no cache whatsoever! (Don't ask me!
I don't know why that should be!)
Anyway, as there are enough articles/text here already, I'll stop now.
Reidar