Mac-PC file transfer
Mac files normally have a Mac-binary, or double-fork structure that the PC cannot handle directly. Therefore, it is convenient to convert any Mac file prior to transferring it to a PC or a PC-based network (or to another Mac via a PC or an on-line service) so that its structure will resemble the binary structure of the conventional PC file. The Mac software to accomplish this is called MacBinary (formerly BinHex), and it is available as freeware from CompuServe (GO MACFF, filename BINHEX.HEX). It is also one of the utilities of Stuffit by Aladdin Systems, v. 3.07 or higher, and comes bundled with some communication programs. MacBinary adds a header consisting of a few (usually 128) bytes to the file. This header contains the file type and creator information and a filename that can be different from the original Mac filename. It acts as a “wrapper,” hiding the double-fork Mac structure for transfer to and storage in a PC system.
When the file is transferred via modem, the MacBinary file transfer protocol (ZModem MacBinary, YModem MacBinary, etc.) automatically creates the binary PC header for the transfer. However, when the transfer is done via diskette or a typical network (or when a Binary, rather than a MacBinary, modem transfer protocol is used), the conversion from MacBinary to Binary format must be done prior to the transfer in a separate step.
If a Mac file is converted to a PC format, e.g. WordPerfect DOS or Microsoft Word Windows, on the Mac and subsequently transferred to a PC, no MacBinary conversion is needed, since the converted file no longer has the double-fork structure of the Mac. Also text-only files (which have no resource fork) need no MacBinary conversion prior to their transfer to the PC, unless they contain non-ASCII characters (accented and other non-English characters, special symbols, etc.).
If a Mac file (MacBinaried as described above) is transferred back from a PC to a Mac, the reverse Binary-MacBinary conversion is needed to strip away the binary “wrapper” and expose the original double-fork Mac structure. This conversion is automatic when using modem transfer with a MacBinary protocol on the Mac side, or manual when transferring via diskette or network.
Note about Text Files: Plain 7-bit ASCII texts without special (non-English or graphic) characters use the same character set on the Mac and the PC, except for the carriage return character, which is one character on the Mac (ASCII # 13), but two characters on the PC (# 13 and Line Feed ASCII # 10). Therefore a text originally created on a PC may show an extra character after each forced line break on the Mac, while a Mac text may not wrap around properly in some PC editors. The extra character can be added or removed on the Mac by searching (in Microsoft Word) for ^13 and replacing it with ^13 ^10 or vice-versa. 8-bit text files (such as texts with accented or other special characters) use different characters for the Mac, DOS, and Windows above ASCII # 128, and a conversion utility is needed for the proper characters to show in each system.
Hope that helps
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