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File Systems and Storage Management

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Key points

  • FAT32 limits a single file to 4 GB regardless of free space
  • NTFS is for Windows, ext4 for Linux, APFS for macOS, exFAT for cross-platform flash drives
  • Formatting erases the drive, so back up before reformatting
  • NVMe over PCIe is faster than SATA
  • NAS is shared network storage; SAN is a dedicated storage network
  • Minimum number of units is always rounded up
On this page
  1. What a file system does
  2. Interfaces
  3. Network storage

What a file system does

A file system is the method by which files are organised on a disk. It is chosen when the drive is formatted, and formatting erases everything already on the drive.

File systemMainly used withKey point
FAT32Older pen drives, cross-device useMaximum single file size is 4 GB
NTFSWindowsSupports permissions, encryption and large files
exFATFlash drives and SD cardsLarge files, works on Windows and macOS
ext4LinuxJournaling file system
APFSmacOS and iOSApple File System

Key point

The 32 in FAT32 refers to 32-bit table entries, not to any size in gigabytes. A 6 GB file cannot be copied to a FAT32 drive even when 20 GB of free space is available.

Example

A file too large message on a pen drive with plenty of free space points to FAT32. The fix is to back up the contents and reformat the drive as exFAT or NTFS, because formatting erases the data.

Interfaces

  • SATA: the common interface for hard disks and many SSDs.
  • NVMe: connects over PCIe and is much faster than SATA.
  • USB: for external drives.

Network storage

  • NAS, Network Attached Storage: a storage device shared over the office network.
  • SAN, Storage Area Network: a dedicated high-speed network for storage, used in data centres.

Formula

Minimum number of discs or drives = Total size divided by capacity per unit, always rounded UP to the next whole number.

Example

Archiving 3 GB on 700 MB CDs: 3 GB is 3072 MB, and 3072 divided by 700 is about 4.39. Four CDs hold only 2800 MB, so 5 CDs are needed.

Exam tip

In any minimum-number question, a part-filled unit still counts as one whole unit. Always round up, never down.

Practice questions

Answer all, then check. Explanations appear after checking.

1What is the maximum size of a single file that can be stored on a FAT32-formatted drive?
2Which file system is the default for Linux systems?
3An officer tries to copy a 6 GB video to a 32 GB pen drive that has 20 GB free, but the copy fails with a file too large message. The drive is formatted as FAT32. What is the most appropriate solution?
4A section has 3 GB of scanned files to be archived on CDs of 700 MB each. What is the minimum number of CDs required?
5Which interface connects over PCIe and is much faster than SATA?

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