File Systems Supplemental

 

Operating SystemFile System(s)Description
WindowsFAT (12, 16 or 32)

This system uses what is known as a File Allocation Table to index the files on the disk. It divides hard disks into one or more partitions (parts) that become letters, like C:, D:, etc.

Simple to implement and use, but can be somewhat slow.

NTFS (New Technology File System)Uses B-trees for indexing, allowing for very fast access times.

Builds on the features of FAT, adds new features, and changes a few others.Recoverable file system that keeps track of actions in the file system.

exFAT (Extensible FAT)

A lightweight file system used primarily in flash storage applications and SD cards.Supports large file size and partition size limits, allowing storage of files over 4GB on compatible devices.

Mac OSHFS+ (deprecated)
APFS (current)

Historically used HFS+ (HFS Plus) file system, replaced by APFS (Apple File System) starting with macOS High Sierra and iOS 10.3+.

Linuxext2, ext3, ext4, XFS, JFS, etc.Linux systems support various file systems including ext2, ext3, ext4.XFS, JFS, and others are also used depending on the Linux distribution and requirements. ext3 is a journaling extension to ext2, and ext4 is its successor.

File Tree Definitions

Node TypeDescription
Root node
  • Only one per tree
  • Has no parent
  • Always also a parent
Parent nodes
  • Always is also a child
    • (except for root)
Child nodes
  • Can be also a parent
  • Can be also a leaf
Leaf nodes
  • Has no children
  • Always is also a child

Each node is TWO of the above

‌Absolute Pathnames

  • Exact location of a file, basically an address

  • ALWAYS starts at the root

Absolute vs Relative pathnames

  • A relative pathname uses us a file/directory path relative to where we are in the file system. If you asked where I live, and you go to NC State and know I live on campus, I might tell you:


    Sullivan Hall Room 101


    This is like an relative pathname because I am giving you the path to my address relative to YOU. You also go to NC State, so I am including the information you need relative to where you are. Note that this address still represents the ”absolute pathname” of my address.


    ‌Pathnames to Memorize


  • The E 115 Course Locker: /mnt/coe/workspace/csc/admin/e115


  • The Your Home Directory : /mnt/ncsudrive/*/unityid
    • Where * is your first letter of your unityID and unityid is your unityIDYour Home Directory: ~/known as tilde slash or squiggle slash

File Names and Extensions

  • Must include extension name
  • Manually changing extension doesn’t change the file type
  • _ (underscores) are OK, spaces are not. No use of / or other symbols.
  • Security concerns: a .exe file might look like a .jpg file.

Simplified NFS Chart