svpillay@phoenix.Princeton.EDU (Kanthan Pillay) (08/19/89)
Can anyone out there tell me a quick and dirty way of checking whether a diskette is MFS or HFS? Ideally, I would like to know how big the diskette is, but knowing whether it is MFS will do for now. Pascal or C? Yes. Kanthan.
blob@apple.com (Brian Bechtel) (08/21/89)
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"
keith@Apple.COM (Keith Rollin) (08/22/89)
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). ------------------------------------------------------------------------------ Keith Rollin --- Apple Computer, Inc. --- Developer Technical Support INTERNET: keith@apple.com UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith "Argue for your Apple, and sure enough, it's yours" - Keith Rollin, Contusions