From: "Chris Jones" <cj7 AT ukc DOT ac DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: LFN and VFAT
Date: Sun, 30 Apr 2000 02:22:37 +0100
Organization: University of Kent at Canterbury
Lines: 11
Message-ID: <8eg1sj$4ak$1@spruce.ukc.ac.uk>
References: <Pine DOT LNX DOT 4 DOT 10 DOT 10004291844030 DOT 19653-100000 AT darkstar DOT grendel DOT net> <3 DOT 0 DOT 6 DOT 16 DOT 20000429225812 DOT 35ffbd86 AT mail DOT cybercable DOT fr> <390B83FA DOT B4A6881A AT mtu-net DOT ru>
NNTP-Posting-Host: stue20c.ukc.ac.uk
X-Trace: spruce.ukc.ac.uk 957057747 4436 129.12.226.12 (30 Apr 2000 01:22:27 GMT)
X-Complaints-To: news AT ukc DOT ac DOT uk
NNTP-Posting-Date: 30 Apr 2000 01:22:27 GMT
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 5.00.2919.6700
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

> Btw, could anyone tell me how CRC is computed for Long File Name
> directory entries? I've never seen any explanation of this LFN field, just
> how names stored and their structure. How to compute that CRC
> out of LFN?

It's computed from the short name, and is also done by LFNDOS - check the
source code for the function (I think it's called) calculatechecksum()  -
it's quite simple really. Ralf Brown's interrupt list also explains it.