Disk First Aid
Encyclopedia
Disk First Aid is a free software utility made by Apple Inc. that is bundled with all computers running Mac OS
either as a standalone application (in the case of Mac OS 9
and below) or as part of the Disk Utility
(in the case of Mac OS X
). This tool verifies and repairs a limited number of directory structure
problems on any HFS
or HFS Plus
hard disk
or volume.
Disk First Aid is a very simple tool, with it only being able to detect and repair directory damage and many books are critical of its sometimes inaccurate reporting of errors, and often suggest to run the tool more than once to ensure you are receiving a consistent result. Disk First Aid is located in
as well is for general maintenance every 6 months.
After analyzing the disk directory, Disk First Aid determines whether it is able to repair any damage that was detected. The utility can commonly only fix problems associated with the catalog/extents files and the volume bitmap. Commonly, the program reports that these is an error, but cannot fix it.
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
either as a standalone application (in the case of Mac OS 9
Mac OS 9
Mac OS 9 is the final major release of Apple's Mac OS before the launch of Mac OS X. Introduced on October 23, 1999, Apple positioned it as "The Best Internet Operating System Ever," highlighting Sherlock 2's Internet search capabilities, integration with Apple's free online services known as...
and below) or as part of the Disk Utility
Disk Utility
Disk Utility is the name of a utility created by Apple for performing disk-related tasks in Mac OS X. These tasks include:*the creation, conversion, compression and encryption of disk images from a wide range of formats read by Disk Utility to .dmg or—for CD/DVD images—.cdr, which is identical to...
(in the case of Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
). This tool verifies and repairs a limited number of directory structure
Directory (file systems)
In computing, a folder, directory, catalog, or drawer, is a virtual container originally derived from an earlier Object-oriented programming concept by the same name within a digital file system, in which groups of computer files and other folders can be kept and organized.A typical file system may...
problems on any HFS
Hierarchical File System
Hierarchical File System is a file system developed by Apple Inc. for use in computer systems running Mac OS. Originally designed for use on floppy and hard disks, it can also be found on read-only media such as CD-ROMs...
or HFS Plus
HFS Plus
HFS Plus or HFS+ is a file system developed by Apple Inc. to replace their Hierarchical File System as the primary file system used in Macintosh computers . It is also one of the formats used by the iPod digital music player...
hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
or volume.
Disk First Aid is a very simple tool, with it only being able to detect and repair directory damage and many books are critical of its sometimes inaccurate reporting of errors, and often suggest to run the tool more than once to ensure you are receiving a consistent result. Disk First Aid is located in
Applications:Utilities:Disk First Aid prior to Mac OS X and at /Applications/Utilities/Disk Utility.app (as part of Disk Utility) in Mac OS X. In Mac OS 9 and below, the system provides an option to run Disk First Aid on startup, although it has been reported that it provides little gain and sometimes can amplify a problem.Situations to use the tool
One source suggests that disk utility should be used when there are:- Frequent system crashesCrash (computing)A crash in computing is a condition where a computer or a program, either an application or part of the operating system, ceases to function properly, often exiting after encountering errors. Often the offending program may appear to freeze or hang until a crash reporting service documents...
- Disappearing files
- Files changing size
- Problems copying files from one place to another.
- Problems saving files.
- Cryptic error messages.
as well is for general maintenance every 6 months.
Analysis
Disk First Aid has built-in capabilities to check for damage to:- Partition MapApple Partition MapApple Partition Map is a partition scheme used to define the low-level organization of data on disks formatted for use with 68K and PowerPC Macintosh computers that was introduced with the Macintosh SE ....
, - Device DriverDevice driverIn computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
, - Boot BlocksBoot sectorA boot sector or boot block is a region of a hard disk, floppy disk, optical disc, or other data storage device that contains machine code to be loaded into random-access memory by a computer system's built-in firmware...
, - Master Directory Block ,
- Volume Bitmap,
- Catalog File,
- Extents File,
- Finder Attributes,
- Disk volume,
- Extent B-tree,
- Catalog B-tree,
- Catalog Hierarchy,
- Volume Info,
- and to search for locked volume name.
After analyzing the disk directory, Disk First Aid determines whether it is able to repair any damage that was detected. The utility can commonly only fix problems associated with the catalog/extents files and the volume bitmap. Commonly, the program reports that these is an error, but cannot fix it.