Search results
Results from the WOW.Com Content Network
zram, formerly called compcache, is a Linux kernel module for creating a compressed block device in RAM, i.e. a RAM disk with on-the-fly disk compression. The block device created with zram can then be used for swap or as general-purpose RAM disk. The two most common uses for zram are for the storage of temporary files (/tmp) and as a swap ...
In 2009 Squashfs was merged into Linux mainline as part of Linux 2.6.29. [ 8 ] [ 9 ] In that process, the backward-compatibility code for older formats was removed. Since then the Squashfs kernel-space code has been maintained in the Linux mainline tree, while the user-space tools remain on the project's GitHub page.
Reiser4 uses B*-trees in conjunction with the dancing tree balancing approach, in which underpopulated nodes will not be merged until a flush to disk except under memory pressure or when a transaction completes. Such a system also allows Reiser4 to create files and directories without having to waste time and space through fixed blocks.
XFS is a 64-bit file system [24] and supports a maximum file system size of 8 exbibytes minus one byte (2 63 − 1 bytes), but limitations imposed by the host operating system can decrease this limit. 32-bit Linux systems limit the size of both the file and file system to 16 tebibytes.
In practice, however, an in-memory red–black tree of page-sized bitmaps is used to speed up allocations. These bitmaps are persisted to disk (starting in Linux 2.6.37, via the space_cache mount option [86]) as special extents that are exempt from checksumming and copy-on-write.
The idea behind tmpfs is similar in concept to a RAM disk, in that both provide a file system stored in volatile memory; however, the implementations are different. While tmpfs is implemented at the logical file system layer, a RAM disk is implemented at the physical file system layer. In other words, a RAM disk is a virtual block device with a ...
The table below shows the default file system, but many Linux distributions support some or all of ext2, ext3, ext4, Btrfs, ReiserFS, Reiser4, JFS, XFS, GFS2, OCFS2, and NILFS. It is possible to install Linux onto most of these file systems. The ext file systems, namely ext2, ext3, and ext4 are based on the original Linux file system.
An otherwise blank disk has five files, A through E, each using 10 blocks of space (for this section, a block is an allocation unit of the filesystem; the block size is set when the disk is formatted and can be any size supported by the filesystem). On a blank disk, all of these files would be allocated one after the other (see example 1 in the ...