Apple File Exchange: A Description (Discontinued)

Overview
--------


Apple File Exchange (AFE) is an application that lets users:

- copy files and directories from one file system to another
- convert files from one file format to another
- transliterate the characters in a file from one character set to another

AFE copies files among three file systems: Macintosh, ProDOS, and MS-DOS.

System Requirements
-------------------
Apple File Exchange runs on any Macintosh that supports double-sided disks. If you want to use Apple File Exchange to read and write MS-DOS disks, your Macintosh must have a SuperDrive installed.

Apple File Exchange is not compatible with any operating system beyond System 7.1. You should use PC Exchange to get the same file translation capabilities in operating systems after System 7.1.

Advantages of Apple File Exchange
---------------------------------
For developers writing translation routines, AFE has important advantages
over other file conversion utilities:

- It performs batch translation of dissimilar files. Files of different
types can be translated in a single operation

- It can move files between Macintosh disks, 800K ProDOS disks, and
5.25-inch MS-DOS disks.

- It is generally available.

- It provides a consistent, easy-to-use human interface for all translations.

- It provides a framework that allows quick development of new translation
routines. Apple File Exchange handles the user interface and provides
file system calls that are the same for all file systems. This frees
developers to concentrate on actual file conversion.

Translators
-----------
A translator is a routine invoked by AFE when it copies a file. These
routines are used to convert a file from one format to another. As part of
translation, translators may also transliterate a file -- that is,
convert the printable characters in the file to the equivalent characters
in another character set.

Although AFE includes several built-in translators, most translators are
produced by independent software publishers. The built-in translators
perform a number of fundamental translations, such as converting text
files from one file system to equivalent text files on another. All other
translations are performed by translators that are separate from AFE.

All translators, with the exception of the fundamental translators built
into AFE, are kept in translator files in the Apple File Exchange folder.

Translator Menus
----------------
Translations are performed using selection menus, or translator menus.

Translator menus are the AFE menus that display currently available
translators. Depending on the disks currently selected, AFE displays either
one or two translator menus:

- If the file systems of both the source and destination disks are the
same, there is only one translator menu. The Mac-to-Mac menu is an
example.

- If the file systems of the source and destination disks are different,
there are two translator menus. One menu contains translators that handle
translations from the first file system to the second (for example, Mac to
ProDOS), while the other menu contains translators that handle translations
in the opposite direction (for example, ProDOS to Mac).

Active and Inactive Translators
-------------------------------
The translators shown in translator menus are either active or inactive.

- Active translators are those that Apple File Exchange will attempt to use
when translating a file.

- Inactive translators are those that Apple File Exchange will not attempt
to use when translating a file.

Users activate and deactivate translators by selecting their names in the
menu. Selecting an active translator makes it inactive, while selecting an
inactive translator makes it active. An active translator is shown with a
check mark to the left of its name in the menu.

General-purpose and Special-purpose Translators
-----------------------------------------------
Each translator menu is divided into parts:

- At the top of the menu are special-purpose translators. These translators
are used in cases where either the source file format or the destination
file format is used by a limited range of applications. Except in very
rare cases, translators written by suppliers other than Apple will be
special purpose translators (for example, MultiMate to MacWrite).

- If translators have been imported to this menu from another menu, they
appear in the middle of the menu.

- At the bottom of the menu are general-purpose translators. These convert
file formats used by a wide variety of applications to other widely-used
formats. One example is a translator that converts text files from one
file system to equivalent text files on another file system. Another
possible example would be a translator for encrypting files. Except in
very rare cases, the only general-purpose translators will be those that
are built into Apple File Exchange.

The parts of the translator menu are separated by dotted lines.
Special-purpose translators are shown in alphabetical order, while
general-purpose translators are arranged by their resource ID numbers.

General-purpose translators have two important limitations that distinguish
them from special-purpose translators:

- They can't be imported into other menus.

- In the dialog box that allows the user to select a translator when more
than one translator can translate a file, general-purpose translators
are not shown. It is assumed that one or more of the general-purpose
translators can translate any file.


Article Change History:
24 Jul 1995 - Reviewed for technical accuracy.

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