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[Dave J. Andruczyk]

> I am trying to get two WFW PC's talking to via Linux/Samba (RedHat 5.2) server
> Interface. One PC continuously streams binary datafile onto its directory on
> the server while the other continuously reads it. Information on the size of
> this file (which can continuously increase up to 3MB) is continuously updated
> and is stored using a fixed width pointer in the file header. 
> It appears that the second PC can't read this pointer and uses its old value.
> Therefore it can not read the file beyond its old time mark. 
> 
> Everything works OK when PC's talk directly to each other (peer-to-peer) 
> without the server. I've tried all the usual fixes with oplocks, permissons,
> etc. in smb.conf but without much success. 
> 
> Is there possibly a way to force an update of the first chunk of data in the
> cache? 

you might wanna fiddle with "read raw, and write raw", along with turning
oplocks on (real oplocks, not the fake ones).

the main problem i can imagine is filesystem caching, where the writes
from the "feeder" computer aren't completed right away, while the other
trys to read..

the solution is to turn on "strict sync"  but that is likely to give you a
severe performance hit.    
see the smb.conf man page for details..

dave