This section explains more about what Bat Filer is doing to your files. If you're already familiar with file TYPEs, CREATORs, and disk VOLUMES (MOUNTed & UNMOUNTed), you can skip to the next section.
TYPEs & CREATORs
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All Macintosh files have two attributes, TYPE and CREATOR. Each of these is a 4-character "code" that identifies the file to the system and to applications programs. The code MUST be 4 characters. A file of type BFT, for example, must be entered as B-F-T-(space character).
A file's creator attribute is exactly that: it identifies the program that created it. This is how the Finder knows what program to start when you double-click a document icon.
A file's type attribute identifies the file's kind or variety. Files which are all ASCII characters have the type TEXT, files which are MacWrite documents have the type WORD, MacPaint documents have the type PNTG. It is only rarely useful to change a file's type attribute; DO NOT change file types unless you know exactly why you are doing it.
Let's look at what happens when you open or print a document file from the Finder to see why these two attributes are important.
• The Finder examines the file's CREATOR, then searches for a file of type APPL (application) with the same creator.
• When it finds it, it "Launches" that program.
• When the program starts, it receives a "message" from the Finder with the name and TYPE of the document that was opened.
• If the program recognizes files of that type, it checks the message it received, to see it the user called for "Open" or "Print". If Print, the program prints the file; if Open, it opens the file - just as if that file were selected using the program's "Open" command.
A common reason for using Bat Filer will be to change documents' creator attributes. For example, if you obtain some clip art paint files, chances are their creator will be set to MacPaint. But, if you are a FullPaint user, Bat Filer can change the creator of the clip art files so that double-clicking them will start FullPaint.
VOLUMES
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A VOLUME is a unit of data storage - floppy disk, hard disk, tape, CD-ROM, etc. - formatted to store files. A Macintosh 3.5 inch disk is a volume. In some cases, a single large device - such as a hard disk - can be divided into several volumes.
Volumes have names. These are the names you see beneath the disk icons in the Finder. These names are useful for identification, but you do not need to use volume names to use Bat Filer.
Volumes contain two kinds of information: FILES and DIRECTORIES. A file is a document, usually seen in the Finder with its own icon. A directory is a catalog of files; directories are represented in the Finder by folders. Directories can contain still other directories; these are sometimes called sub-directories. The top-most or disk level directory is called the ROOT directory.
A file on any particular disk can be specified by:
• The file's name.
• The name or ID of the directory that contains it.
• The name or ID of the volume that contains it.
Files are sometimes identified by PATHNAME. This begins with a volume name, then the names of all directories and sub-directories (each preceded by a colon) that lead to the file, then finally, the file name itself. An example of a pathname:
My Disk:Documents:Letters:Personal:Mom 5/8/88
^ ^ ^ ^ ^
Volume Directory SubDir SubDir File
Volumes can be MOUNTED or UN-MOUNTED, ON-LINE or OFF-LINE. When you insert a 3.5 inch disk into a Macintosh drive, the Macintosh operating system MOUNTs the volume represented by that disk. You can think of this as a disk being "recognized". Once a volume has been mounted, the files and directories on it are available for use.
A mounted volume can either be ON-LINE or OFF-LINE. (In Bat Filer, and most Macintosh programs, this applies to 3.5 inch disks only; hard disks are never placed offline.) ON-LINE means the volume is in a drive ready to be accessed; OFF-LINE means that the volume is "known" by the system, but not presently in any drive. In the Finder, highlighting a disk icon and selecting "Eject" ([Command]-E) will eject that disk, but the disk icon does not disappear; instead it become gray. This indicates that the volume represented by that disk is mounted, but not currently online. If you try to access files on an offline volume, you will see the "Please insert the disk..." alert box.
UNMOUNTing a volume reverses the mounting process. When a volume is unmounted, the operating system no longer "knows" about it. This is equivalent to dragging a disk icon into the Trash in the Finder. If you try to access files that are on an unmounted volume, you will see a "volume not found" error message.
Some Bat Filer operations (such as "Find Files") apply to all mounted volumes. You can use the "Mounted Volumes" command to see what volumes are currently mounted.
FILES & FORKS
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A Macintosh file consists of two "forks", the data fork and the resource fork. The data fork is what on other microcomputer systems is usually the entire file: information written as a stream from the file's beginning to end. The resource fork is information specially organized so as to be accessible to the Macintosh Toolbox Resource Manager. The Bat Filer file list shows for each file the length of both forks.
Files which are documents usually contain most of their information in the data fork; files which are applications contain most of their information in the resource fork. In using Bat Filer, all you need to know is that the size of the two forks combined gives the total size of a file.
