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From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MFS vs. HFS -- Help wanted
Message-ID: <34183@apple.Apple.COM>
Date: 21 Aug 89 19:50:53 GMT
References: <10002@phoenix.Princeton.EDU> <3716@internal.Apple.COM>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 28

In article <3716@internal.Apple.COM> blob@apple.com (Brian Bechtel) writes:
>In article <10002@phoenix.Princeton.EDU> svpillay@phoenix.Princeton.EDU 
>(Kanthan Pillay) writes:
>
>>         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.

Thanks for the tip on this Brian. I just wanted to add on thing. We get a lot
of developers who try to use this equation, and get upset when it doesn't work
in all cases. It is important to remember - especially in Pascal - that
ioVNmAlBlks is an UNSIGNED quantity. If you don't take that into account, you
often get negative results.

This is shown in DTS Sample Code #018: StdFile (plug, plug).


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"Argue for your Apple, and sure enough, it's yours" - Keith Rollin, Contusions