Generic hierarchical file system software

#Generic hierarchical file system software mac os x
#Generic hierarchical file system software plus

Allocation File вЂ“ This file stores the information about used blocks. Records up to eight file extents per file.Д¤. Each record can be between 4 KB and 8 KB (HFS records were 512 bytes). Catalog File вЂ“ a B-Tree file that contains folder and file records. The volume Header contains volume information as well as the location of the Catalog File and Extent Overflow File.ДЈ. The Volume Header is similar to the Master Directory Block (MDB) of HFS. Volume Header - Block 2 holds the Volume Header. Boot Blocks - Blocks 0 and 1 contain the Boot Blocks to load the Operating SystemДў. Files can now be secured from being accessed even when a hard disk is removed and attempted to be accessed in another system.Д®ach HFS+ volume is made up of nine sections as follows:ДЎ.

#Generic hierarchical file system software mac os x

The addition of compression added the ability for more drive space by compressing files.ДЇor security, Mac OS X 10.7 added the ability of encryption.

With the release of Mac OS X 10.6, HFS+ was updated by adding support for compression. When one file is modified, it is written to another spot on the disk and the pointer is changed for the modified file. Until one file is modified, this remains true. Two files on the HFS+ volume really only occupy the space of one file. In the B-Tree containing the file allocations, the physical address for File1 and File2 are the same. For example, we create File1 in DirectoryA and then copy it to DirectoryB. When a copy is made of the file and the file is renamed, then two files point to the same address. The pointers are associated with a file name for example, and points to the address of the physical file. Hard linking is the ability of a directory and file structure to use pointers. In Mac OS X 10.5, hard linking was added. ACLs allow permissions of not only who can access a file, but what they can do to the files such as read, write, modify, delete, etc. Mac OS X 10.4 included HFS+ support to include Access Control List (ACL) permissions. HFSX did not need the ROM support to boot. The wrapper is when the ROM contains support to allow an HFS+ volume to boot. Also, the HFSX is identical to HFS+, but it does not need the HFS Wrapper. This system allowed for optional case sensitivity with directory and file names. Journaling is a method to allow data/metadata to be recovered in case of an improper shutdown.ДЄnother option which came with OS X 10.3 was HFSX. HFS+ with journaling is sometimes referred to as HFSJ. With OS X 10.3, Journaling was enabled by default on HFS+ volumes. With Mac OS X 10.2.2, Apple updated HFS+ to include Journaling.

HFS+ uses a 32-bit integer for addressing, making the maximum number of files 4,294,967,295 on a volume. HFS uses 16-bit integers for addressing limiting the maximum number of files. HFS+ was introduced to replace the standard Hierarchical File System (HFS). Stored dates can be in the range of Januto Februjust like with HFS. The file allocation is stored in a bitmap file, while bad blocks are tracked by a B-Tree file. The directories and their contents are managed by a B-Tree file. The maximum file name length is 255 characters using UTF-16 characters. The maximum volume size supported by HFS+ is 8 Exabytes with a maximum file size of 8 Exabytes.

#Generic hierarchical file system software plus

The Hierarchical File System Plus (HFS+) was introduced in Januby Apple Computers as an enhancement of their HFS file system.