File System Implementation Flashcards
(33 cards)
⭐️ Give the definition:
How files and directories are represented
On-disk structures
What structure is the common file system structure?
Data block
Inode table
Directories
Data bitmap
Inode bitmap
Superblock
(DIDDIS)
What in the file system is divided into blocks?
The disk
⭐️ What do we call the simple layout of a file system?
Very Simple File System (VSFS)
⭐️ What blocks reserve a fixed portion of disk?
Data blocks
⭐️ What sort of table is this:
Stores inodes, where each inode is 256 bytes & a block of 4KB can store 16 inodes
Inode table
What does an inode table use its pointers to to indicate?
Block numbers
What does this formula find?
(inode_number + sizeof(inode_table)) / block_size)
The block an inode is in
Give the definition:
Index node
Inode
What sort of pointers used by an inode table refer to a data block?
Direct pointers
What sort of pointers used by an inode table have an issue with limited size?
Direct pointers
What sort of pointers used by an inode table refer to a block containing more pointers?
Indirect pointers
What sort of pointers used by an inode table have an issue with overhead & 2 disk reads for each access?
Indirect pointers
What sort of pointers used by an inode table have some direct & some indirect pointers?
Hybrid pointers
Are hybrid pointers better for small or big files?
Small
If the file that a hybrid pointer is going to point to is large what sort of index do we use?
Multi-level index
What are the two approaches for pointers with an inode table that don’t use pointers?
Extent-based & linked lists
⭐️ Give the definition:
A special type of file
Directories
What on-disk structure is this design common for?
Storing directory entries in files
Directory
Give the definition:
Total bytes for a file name & any left over space in a directory
reclen
Give the definition:
The actual length of a file name in a directory
strlen
What are bitmaps used for?
Allocation
What are the two on-disk structures that can be used by a file system to find free data blocks/inodes?
Free list & bitmap
Give the definition:
An on-disk structure that points to the first free block
Free list
