allocation block 窶 Each volume is segmented into a series of blocks called allocation blocks. These allocation blocks store data for the drive. All the allocation blocks on a given drive are the same size. This size is directly related to the size of the volume. This size is a multiple of 512 bytes. Thus, the smallest possible size of a file that has data is the size of this allocation block. This is why, if you create a 1-byte file on a large HFS drive, the size of that file could be 65 kilobytes in size.
application 窶 A program used to do work on your Macintosh, such as a word processor, spreadsheet, or graphics program.
bad sector - A sector on the media that did not store the data correctly, making the sector unreadable and unuseable.
Boot Blocks - The first two blocks of every Mac disk which tells your Mac that the disk can be used as a startup disk or not. If it is a bootable disk, these blocks will also tell it how to boot this volume.
bundle bit - A flag maintained by every file which informs the system that the file uses a custom icon or set of icons. If the bundle bit flag is incorrectly set, the file's icon may display improperly.
Catalog Tree - This is a dynamic structure that keeps a list of all the files and folders on the drive.
cdev (see control panel)
Chooser 窶 A program which lets you select which devices, such as printers and network file servers, to use with your Macintosh.
clump size 窶 This is a size used by the system to allocate a "chunk" of space for additional data. For example, if a file is appended to, the file system attempts to add this amount to the end of the file. This size is a "chunk", or clump, of allocation blocks.
configuration 窶 The combination of hardware, installed system software, system settings, and peripheral devices that make up a Macintosh system.
conflict 窶 When two or more software or hardware items installed on a single Macintosh system do not function properly when used together. The result of most conflicts is system crashing and loss of data.
control panel 窶 A program that lets you customize specific features and settings for your Macintosh system. They are accessible from the Control Panel desk accessory under System 6, or in the Control Panels folder under System 7.
crash 窶 Abrupt termination of a program resulting from a problem occurring in the software. A system crash or 窶彷reeze窶 is where the system software ceases to function and the whole machine 窶徑ocks up.窶
creator code - The identification code of the application and the files it creates.
deleted file - A file that has been dragged to the Trash. This file is deleted only after the trash has been emptied. Until new data is written to the sectors freed up by the deleted file, it is generally recoverable.
desk accessory 窶 Very small application programs usually installed under the Apple menu.
driver 窶 A program that allows your Macintosh communicates with a specific device such as a printer or scanner.
Extents Tree - This is a dynamic structure that keeps a list of all the fragmented structures on the disk. Normally this refers to fragmented files, but it can also refer to internal structures, such as a Bad Block file, Catalog Tree fragments, or additional Extents Tree fragments.
extension (see system extension)
Extended HFS (see HFS Plus)
head crash - A disk malfunction where the read/write heads have physically scored the disk media. If the disk is left running, the disk will eventually destroy itself.
HFS - Hierarchial File System. Macintoshes older than the Mac 512 used MFS, not HFS file system. HFS is a system used to organize the data on your disk.
HFS Plus - A variation of the classic HFS system. HFS+ modifies how allocation blocks are used, thus reducing waste per file on the drive. It also embraces Unicode, although, to this writing, the Finder does not. This new HFS was introduced with System 8.1.
INIT (see system extension)
knowledgebase 窶 A database of rules and information used by MacMedic邃｢ to find conflicts, incompatibilities, and other problems.
mount - The process of making a disk (or partition on a disk) available for use. When a disk or partition is mounted, it is available on the desktop and ready for use.
RAM 窶 Random Access Memory. This is the part of the computer窶冱 memory where system software and applications are executed, and data from documents are manipulated.
report 窶 The resulting output generated by MacMedic邃｢ System Configuration after inferencing collected system information against information in the knowledgebase.
resource fork - the portion of a file that stores the file's resources (i.e. its dialog screens, pictures, menus, code, etc.). If the resource fork of a file is damaged, it will most likely be unusable.
system extension 窶 A program used to add features to the system software. Extension files are located in the Extensions folder, located in the System Folder.
System Folder 窶 The folder on your startup volume where all of the Macintosh operating system software and its related software and documents are installed. Under System 7, this folder contains folders which help keep your Apple menu items, control panels, extensions, fonts, and startup items organized.
system software 窶 The software which handles all of the basic operations of a computer which make it usable, upon which other software is built and executes. Occasionally the system software must be reinstalled or upgraded to resolve conflicts or incompatibilities.
verify a disk - The process of reading sectors on a disk and checking for errors.
volume 窶 A storage medium which has been installed and formatted to use with your Macintosh for storing and retrieving software and information.
Volume BitMap - This is a file on the drive that keeps track of what alloation blocks are in use and those that are free.
Volume Information Block - The primary directory file of a volume. The Volume Information Block (VIB) contains the type of HFS used, the location of the Catalog and Extents Trees, and the quantity of files and folders in the volume.
