From:	Martin Str|mberg <ams AT ludd DOT luth DOT se>
Message-Id:	<199807271748.TAA29763@father.ludd.luth.se>
Subject:	Re: A call to `sync' inside `spawn'
To:	eliz AT is DOT elta DOT co DOT il (Eli Zaretskii)
Date:	Mon, 27 Jul 1998 19:48:11 +0200 (MET DST)
Cc:	djgpp-workers AT delorie DOT com (DJGPP-WORKERS)
In-Reply-To:	<Pine.SUN.3.91.980727131758.29918E-100000@is> from Eli Zaretskii at "Jul 27, 98 01:18:16 pm"
MIME-Version:	1.0

According to Eli Zaretskii:
> 
> On Sun, 26 Jul 1998, Martin Str|mberg wrote:
> 
> > I suppose that there is no way to flush the _write_ cache and not the
> > read cache?

[Klippa, klapp, kluppit DOZE mess.]

> In any case, the call to `sync' before running a child program doesn't
> even need to flush the write cache.  It just needs to make sure output
> to the same file/device doesn't appear out-of-order, for which the DOS
> CommitFile function is enough.  IMHO, this is simply a DOS bug (it
> should have done that in our stead, inside its Exec function) which we
> are working around.  I can hardly believe any Unix box calls `sync',
> since the `sync' system call is typically prohibitively expensive on
> Unix (it takes several seconds even on fast machines).

No, I was thinking the sync call. It's such a waste to forget the read
cache, when it's not necessary. 

And sync on my machine (Linux) doesn't take several seconds. Less than
one, actually, and it's not idle.

> Anyway, I'm not sure you can distinguish between ``read'' and
> ``write'' cache, since the cacje itself usually doesn't.  But if you

Eh! Of course you can distinguish between read and write cache. It's
rather necessary to do so: you have to flush the write buffers if
you're rebooting. Perhaps I didn't understand what you meant?

> know how to flush the cache without invalidating it, please tell.  In

How about "smartdrv/s"? But perhaps this also invalidates the read
cache and perhaps there's other caching utilities on (WIN)DOZE that I
don't know about? You seem to say so. 


Silence,

							MartinS

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