Lanman's use of the cache manager

NTFSD
1

I have been looking at filtering Lanman read/writes on NT4. It seems
that it always uses the normal cache manager for reads (except of course
for paging and IRP_NO_CACHE), but for writes it some times does and
sometimes doesn’t. For instance writing a file using edit does not seem
to use the cache, while writing with notepad does.

I know it doesn’t have to use the cache manager if it doesn’t want to,
but does anyone have an idea how it chooses what to do?

Thanks
Shaun

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2

I shall answer my own question 8*>

If the file is opened for write only, Lanman doesn’t use the cache
manager. If it is opened for write AND read (or just read), then it
does.

Shaun

Shaun wrote:
>I have been looking at filtering Lanman read/writes on NT4. It seems
>that it always uses the normal cache manager for reads (except of course
>for paging and IRP_NO_CACHE), but for writes it some times does and
>sometimes doesn’t. For instance writing a file using edit does not seem
>to use the cache, while writing with notepad does.
>
>I know it doesn’t have to use the cache manager if it doesn’t want to,
>but does anyone have an idea how it chooses what to do?
>
>Thanks
>Shaun
>
>
>
>
>
>—
>You are currently subscribed to ntfsd as: xxxxx@sdlabs.demon.co.uk
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3

But you should be careful - this default caching heurustics can be changed
via registry settings.
See the MS KB article “How to Disable Network Redirector File Caching”.

BTW, it would be nice to have this article updated for Win2K, if there is
anything to update.
Default behaviour seems to be the same.

Certainly there is a disassembly option, but something published may be
treated as “set in stone” -:)).

Vladimir

----- Original Message -----
From: “Shaun”
To: “File Systems Developers”
Sent: 21 ÆÅ×ÒÁÌÑ 2001 Ç. 20:57
Subject: [ntfsd] Re: Lanman’s use of the cache manager

> I shall answer my own question 8*>
>
> If the file is opened for write only, Lanman doesn’t use the cache
> manager. If it is opened for write AND read (or just read), then it
> does.
>
> Shaun
>
> Shaun wrote:
> >I have been looking at filtering Lanman read/writes on NT4. It seems
> >that it always uses the normal cache manager for reads (except of course
> >for paging and IRP_NO_CACHE), but for writes it some times does and
> >sometimes doesn’t. For instance writing a file using edit does not seem
> >to use the cache, while writing with notepad does.
> >
> >I know it doesn’t have to use the cache manager if it doesn’t want to,
> >but does anyone have an idea how it chooses what to do?
> >
> >Thanks
> >Shaun
> >
> >
> >
> >
> >
> >—
> >You are currently subscribed to ntfsd as: xxxxx@sdlabs.demon.co.uk
> >To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
>
>
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@aha.ru
> To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com

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