Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wasatch!cs.utexas.edu!usc!apple!apple.com!blob
From: blob@apple.com (Brian Bechtel)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MFS vs. HFS -- Help wanted
Message-ID: <3716@internal.Apple.COM>
Date: 21 Aug 89 14:27:08 GMT
References: <10002@phoenix.Princeton.EDU>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 20

In article <10002@phoenix.Princeton.EDU> svpillay@phoenix.Princeton.EDU 
(Kanthan Pillay) writes:
> Can anyone out there tell me a quick and dirty way of checking
> whether a diskette is MFS or HFS?

To check if a volume is HFS or MFS, call PBHGetVInfo.  In the field 
ioVSigWord, the two values you're looking for are $42$44 (HFS) or $D2$D7 
(MFS).


>         Ideally, I would like to know how big the diskette is, but
> knowing whether it is MFS will do for now.

To find the size of a volume, call PBHGetVInfo.  The size is the product 
of the number of allocation blocks and the allocation block size. 
(ioVNmAlBlks * ioVAlBlkSiz)

See page IV-130 and IV-123-124 of Inside Macintosh for more details.

--Brian Bechtel     blob@apple.com     "My opinion, not Apple's"