Hi, folks! Perhaps what I'm going to say is known by most of us, but I think that it isn't bad to remember it, and that it's a good idea to look at it as a whole ;-) .
When transferring files between the PC and the Mac, you have to take into account two differences between them. The first is the filesystem: PC's diskettes use FAT12, where Macintosh diskettes use HFS. That's the obvoius one. Second difference is that PC's files have only a stream of bytes, but Macintosh files have *two* parallel byte streams, called "forks": the "data fork" and the "resource fork". The data fork is used to keep binary data (i.e., documents, pictures, etc.). The resource fork is used to keep executable code and "resources" - pieces of data used by the executable code. The problem is that when we transfer a file from the Macintosh to a PC, a Unix box or other kind of computer that doesn't support forks, if we do nothing speciall we will only transfer the data fork. With documents that's not a big problem, because most Macintosh applications' document format use only the data fork. But applications themselves, system extensions (INITS/CDEVs/drivers/whatever), icon files and other kinds of files do have both forks - and store the most important content on the resource fork. This problem also happens when we download a file from the Internet directly with our Macintosh. Internet protocols (like HTTP and FTP) don't know anything about forks. To solve this, two formats have been created that "pack" both the data and the resource forks in a single data stream that can be uploaded securely to other kinds of computers. These formats also store Macintosh-specific file information, like the creator and the type of the file. The formats are BinHex and MacBinary, and the standard file extensions associated with them are .hqx and .bin, respectively. Thus, when you get with a PC a Macintosh file from the Internet, you need to know what kind of file it is before transferring it to a Macintosh diskette using TransMac, HFV Explorer or any simmilar software. As a sule of thumb, you can look at the file's extension. If it is .hqx, it's encoded with BinHex. If it is .bin, it's encoded with MacBinary. And if it's other extension, it probably is a raw data file, equivalent to a data-fork-only in the Macintosh. You need to set up properly TransMac for that file before attempting to copy it. And I don't think the Auto-detect option is a good one: that one fails sometimes... The forks are also the guilty of us not being able to copy a downloaded file to our Macintosh using a PC-formatted diskette and PC Exchange: even if Apple has defined extensions to the FAT12 filesystem to support Macintosh extended features (like the resource fork, creation date/time, type/creator info, etc.), the PC doesn't know about that extensions, and creates plain files that are seen by MacOS as data-fork-only files... Of course, you can allways copy a BinHex or MacBinary file to a PC diskette, use PC Exchange to open the diskette and copy the file to the Mac's hard disk, and then unencode with the corresponding Macintosh application - I'm sorry I don't know which one should be used for BinHex or MacBinary. Anyone can help me here? About the disk images: disks can be seen also as a series of sectors (chunks of data of fixed size), and thus, as a stream of bytes. A disk image is a file that contains a byte-by-byte copy of an actual diskette. This includes also some "hidden" parts of a diskette, like the boot sector, the root directory and the directory structures. In other words, when you make a disk image of a disk containing several folders and files with data and resource forks, you obtain a single byte stream that contains all the files, folders and attributes of the original disk. And, because it is a single byte stream, it can be transferred as a standard file to PCs and Unix boxes, and is really a data-fork-only file on the Macintosh. Standard disk images are one of the most compatible formats I know, and can be read/written from/to diskettes without problems on any platform/OS. That means that you can not only create Linux boot diskettes from DOS/Windows, but also use the same tools to create Apple ][ or Macintosh diskettes or disk images. There are ven some utilities in both the PC, the Mac and Unix that let you access a disk image like a file archive or even the same way as if it were a real device. I must add that PC hardware isn't able to read/write Macintosh 800 Kb disks, and that early Macintoshes (non-Superdrive) aren't able to read/write PC 720 Kb disks. But provided the image is 1.440 Kb in size and the Macintosh has a SuperDrive (or two :-) ), you can use a PC to create the diskette from the disk image. However, if the image file we have downloaded from the Internet is compressed, we will need to uncompress it before writting it to a diskette. If it's compressed using ZIP, the more common format on the PC, there isn't any problem, but it is not ussual. Most times we will have a Macintosh compression format, and will end up having to carry the file to the Macintosh, uncompressing there, and using Apple's Disk Copy in order to create the diskette - an uncompressed disk image doesn't fit in a diskette, because it contains more data than just the files, so you can't carry it back to the PC. Greetings, Antonio Rodr�guez (Grijan) <ftp://grijan.cjb.net:21000/> -- Compact Macs is sponsored by <http://lowendmac.com/>. 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