Module 13 Vocab Flashcards
Disk Block
basic logic unit of storage on disk of a contiguous set of bytes
Superblock
contains basic information about the file system, including the file system size, list of free blocks, list of allocated blocks, and time of the last modification to the partition; the superblock can be read into memory at boot time
Disk Partitions
logical split of the actual disk drive. The operating system views each partition as a distinct disk, and different operating systems may be run in each split; each partition has at least one directory, in which all the partition’s files are listed.
Boot Blockk
contains information on the disk layout and code for loading the operating system into the kernel space
Free Space Data Structure
tracks the free blocks in the disk
I-Nodes List
stores information about the individual files stored on disk, and allocatable blocks for directories and file systems
Master Boot Record
stores information about the entire drive
Parition Table
specifies the beginning of each partition
Contiguous Allocation
each file occupies a contiguous region of blocks
Disk Space Allocation
managing data in the disk with the aims to ensure fast sequential access, fast random access, the ability to grow a file system quickly, and to minimize fragmentation
File Allocation Table
stores a condensed version of the linked list to be stored at the beginning of the file system; the file is stored in allocated clusters
linked List Allocation
hold a linked list of blocks for each file such that each block contains a pointer to the next block
Linked List with Indexing or i-nodes
supports direct access to the file’s blocks by storing files in the i-node data structure
Link-counter
counts the number of ways that an i-node can be retrieved along different paths
i-node (index node)
a kernel structure storing information about each file in the file system; contains a pointer to the disk blocks containing the file’s data, and information such as the file permissions, ownership, modification time, and file type
Directory
a file that holds the list of filenames and their inodes; provides information needed to find the disk data blocks of a file
Hard Links
to represent two different paths for a file, create a single i-node and have two directory entries that point to the same i-node; relies on the link-counter
Symbolic/soft link
the original file has its own i-node and for each reference or path to the file, there is a separate i-node, of type LINK, for a file that just contains the path name to the original file
Free Space Management
tracking unallocated blocks in a portion of the disk partition
Bitmap
maintains for the entire disk partition with one encoding the fact that the block of a particular number is free and zero otherwise
Linked List
List storing the free blocks
In-memory cache
uses a scheme to store blocks that are likely to be requested from disk, to shortcut the need for a disk search and propagate the data to the requesting process
LRU Scheme
given the limited in-memory cache size, evicts the least recently used block from the cache when new blocks are being added in
Incremental Backups
every time you synchronize with your server, it will only backup files that have been changed since the last time
Logical Backup
Copies files from one disk to another
Physical Backup
Physical copy block by block from one disk to another
