> If I save an HFS+ formatted file to, say, a zip disk, can I read it on > another computer that is NOT HFS+ formatted.
There are two issues involved here with the way that files are stored on Macs. Issues relating to HFS vs HFS+ are mostly to do with how the Mac organises storage of files on the hard disc (in terms of sectors and so on), but this has no effect on the content of the files themselves. A file can be transferred between HFS and HFS+ and back, and will remain unchanged in the process. So yes, you can save a Mac file to a Mac Zip disc just the same as before. To all extents and purposes, HFS and HFS+ behave exactly the same, and you will not see any difference. > On any compatible OS, or just 8.1 and over? What about reading a > text file on a PC or Virtual PC? The issue that people refer to when mentioning Mac OS 8.1 is that discs formatted as HFS+ themselves cannot be read by Mac OS 8.0 and below, because the HFS+ format wasn't introduced until Mac OS 8.1. If your hard disc is formatted as HFS+, this means that if you boot the Mac from an CD-ROM with Mac OS on of a version less than 8.1, the hard disc's contents will not be accessible. The same will be true if you take the drive out and put it in another Mac running older Mac OS. If it is possible to format a Zip/Jaz/external hard disc to HFS+, then it too will not be accessible to machines using older Mac OS. However, for the moment, all that is being suggested is that you change the hard disc format, so as long as you have a bootable OS/recovery CD of 8.1 or later, you're OK. However, due to problems of Macs not being able to boot newer CDs, if your Mac can only boot from the original 7.6.1 CD then it would be strongly advisable to ensure that it can boot from a newer system CD before making the hard disc inaccessible to the original CD. Now, you're referring to transfer of data between non-Mac systems. HFS+ makes no difference to this, as it has no bearing on the content of the file itself, or the way that files are stored on discs of other operating systems. However - something that I did observe when sharing a DOS Zip disc between Mac OS 7.6.1 and 8.5.1 was clashes between the way that each OS version stores Mac data on the disc. Mac files are stored in up to three parts - the Finder information (Finder flags (locked, stationery, has custom icon, etc), modified date, etc), the data fork, and the resource fork. Storage of all that data on a PC disc such that the file remains unchanged and readable by the PC is impossible. If you transfer a Mac file over the Internet without encoding, all but the data fork is just discarded, often rendering the file useless; the file needs to be specially encoded and wrapped up for transport. However, with PC discs, the Finder information and resource fork are stored, hidden, in special places on the disc, and there are extra, special files to store data such as folder window width, height and so forth. The PC Exchange or File Exchange system (see Control Panels) deals with storage and retrieval of that information when writing to and reading from PC discs. What seemed to be happening was that the special data stored on the disc by the 7.6.1 and 8.5.1 versions of PC/File Exchange were incompatible and modifications to that hidden Mac data by one version was rendering it corrupted for the other version. The effects were spectacular - on opening of a folder on the Zip disc in 8.5.1, icons would transmute into others, or whole groups of icons would repeatedly disappear and re-appear. Thus, if you start having problems with PC Zip discs that were used in 7.6.1, and now 8.1 or higher, copy off all the files on whatever OS they still appear correctly on, and then clear off all the files under Windows, or re-initialise the disc on the Mac. If the files all have the correct extensions, and the extensions are set up in File Exchange OK, then you can delete only the hidden files (e.g. Finder.dat, resource.frk) in Windows (and this is necessary if some icons no longer show up on the Mac), but if extensions are not mapped to Mac files correctly, this can result in all data being unusable to less-knowledgableMac users. If you are only upgrading from 7.6.1 to 8.1 or higher (and the disc will no longer be accessed by 7.6.1), you may as well get all the data off the disc and reformat it before any damage can set it. Hope that didn't bore you to death or confuse the hell out of you :) To summarise: Yes, you can work with Mac discs just the same as ever Yes, you can work with PC discs and machines the same as ever, but beware of incompatibilities relating to sharing removable discs between older and newer versions of Mac OS. - Daniel. -- StarMax is sponsored by <http://lowendmac.com/> and... / Buy books, CDs, videos, and more from Amazon.com \ / <http://www.amazon.com/exec/obidos/redirect-home/lowendmac> \ Support Low End Mac <http://lowendmac.com/lists/support.html> StarMax list info: <http://lowendmac.com/lists/starmax.html> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/starmax%40mail.maclaunch.com/> Using a Macintosh? Get free email and more at Applelinks! <http://www.applelinks.com>
