Coda File System

Re: Few Basic Coda questions...

From: Marc Schnieder <>
Date: Thu, 27 May 1999 21:47:36 +0000
SOM Bandyopadhyay wrote:

> 4. How is CODA client's performance when using Windows explorer and browsing the network? Does Venus tries to bring the entire file when explorer does a FIND_FIRST/FIND_NEXT operation? If so, isn't there a heavy degradation of performance?
> 5. What is the Win32 function call on which Venus starts caching the entire file? Is it Win32 Open? Find_FIRST/FIND_NEXT? or something else?

Venus caches entire files when they are opened by an application. In
windows this is done by the CreateFile Win32 API function. The
FindFirst/Next functions search for files and are called by the Windows
explorer to browse directories. Calling these functions does not cause
Venus to fetch the files from the servers. Directories however are
fetched and cached since they need to be opened to be read.

Overall it depends on the user level application (in this case Windows
Explorer) if the files are cached (opened) during browsing directories.
Binaries (i.e. .exe files) will be opened by the explorer to extract the
icon. This will cause Venus to fetch the file.

If there are many large binary files in a directory that is listed by
the explorer you will see performance degradation. In fact, the system
might be unusable when working on a weak network. But if the files are
hoarded/cached and the kernel cache has been warmed up, Coda is faster
than Samba and in certain scenarios even than the local disk.

Received on 1999-05-27 17:48:34