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-c, display a grand total of the disk usage found by the other arguments-d #, the depth at which summing should occur. -d 0 sums at the current level, -d 1 sums at the subdirectory, -d 2 at sub-subdirectories, etc.-H, calculate disk usage for link references specified on the command line-k, show sizes as multiples of 1024 bytes, not 512-byte
In computer file systems, a cluster (sometimes also called allocation unit or block) is a unit of disk space allocation for files and directories.To reduce the overhead of managing on-disk data structures, the filesystem does not allocate individual disk sectors by default, but contiguous groups of sectors, called clusters.
In computer file systems, a block allocation map is a data structure used to track disk blocks that are considered "in use". Blocks may also be referred to as allocation units or clusters. [1] CP/M used a block allocation map in its directory. Each directory entry could list 8 or 16 blocks (depending on disk format) that were allocated to a file.
The direct benefit is in storing each range compactly as two numbers, instead of canonically storing every block number in the range. [1] Also, extent allocation results in less file fragmentation. Extent-based file systems can also eliminate most of the metadata overhead of large files that would traditionally be taken up by the block ...
In contrast, the Commodore 1581 disk drive used 5 bytes for the bitmap because the disk format had 40 blocks per track (note 5 bytes can hold 40 bits). [8] In the bitmap of any format, a 1 bit indicated the block was available (free), while a 0 bit indicated the block was not available (used), and the bitmap data was stored low-byte first.
Starting with DOS 5.0, the system ensures that drive C: is always a hard disk, even if the system has more than two physical floppy drives. While without deliberate remapping, the drive letter assignments are typically fixed until the next reboot, however, Zenith MS-DOS 3.21 will update the drive letter assignments when resetting a drive.
Block suballocation addresses this problem by dividing up a tail block in some way to allow it to store fragments from other files. Some block suballocation schemes can perform allocation at the byte level; most, however, simply divide up the block into smaller ones (the divisor usually being some power of 2). For example, if a 38 KiB file is to be stored in a file system using 32
A block, a contiguous number of bytes, is the minimum unit of storage that is read from and written to a disk by a disk driver.The earliest disk drives had fixed block sizes (e.g. the IBM 350 disk storage unit (of the late 1950s) block size was 100 six-bit characters) but starting with the 1301 [8] IBM marketed subsystems that featured variable block sizes: a particular track could have blocks ...