Explanation Of Common Computer File Systems

There are many different File Systems which are used on today’s modern computers, but which one should you use? Here at Affordable Computer Repairs and Service, we will be looking at some old and more mostly new File Systems and explaining which and why.

A File System holds all your files on a computer’s Hard Disk Drive (mechanical) or its SSD (Solid State Drive) or Flash Drive (Thumb/USB/Stick) or SD card. Not only your files are held on there but the Operating System’s files as well. These are the different “storage” options on computers, tablets, iPads, iPhones and Android phones. So really we are talking about “storage” and how that is “formatted” on different device’s.

File Systems & Storage Space

When a storage device is “formatted” it divides up the area (usually in Gigabytes today) into virtual compartments known as “clusters” with an index where different files or parts thereof are located. Also, any available free space is also listed in this index (think filing cabinet with a card index stating which “file” is where). So when a new file is ready to be written to disk (or saved) the File System knows where to put it without deleting something else. The same applies when a file is deleted, it’s “space” then becomes “freely” available for another file to be written to it. What actually happens is the file is left where it is “for now” but the index of the storage is updated therefor making that “space” now available to be written to. This is how your “lost or deleted data” can be retrieved, but that’s for another article.

Allocation Unit Size or Block Size

Now I used “cluster” above but it is known as “allocation unit size” in the Windows Operating System or “block size” in UNIX (Linux, macOS/OSX). These are the smallest size that can normally be accessed by the Operating System to store data. So for Windows computers since Windows NT the default maximum cluster size for NTFS (New Technology File System) is 4 kilobytes (KB) – 4096 bytes. However, on something like a large 16TB storage drive the cluster size changes to 8 KB for more efficiency.

Types of File Systems

Pre-2015 Apple computers will generally have a block size of 512 bytes (OSX Operating System) and after 2017 Apple computers (macOS Operating System) have a block size of 4096 bytes. The former is known as HFS+ = Hierarchical File System Plus and the latter as APFS = Apple File System.

1. FAT32 is an old format for a File System introduced in 1996 with Windows 95 and it comes from the days of MSDOS whereby FAT is File Allocation Table and 32 is for 32GB of drive size or storage space. Now it started life as just FAT then FAT12 onto FAT16 then FAT32 as the disk drives became larger and larger over time. The maximum file size for FAT32 is 4GB, which means there is a limitation of a file that can be copied to a FAT32 storage device of 4GB. Usually, at the moment we see small Flash Drives under 32GB with FAT32 format. FAT32 is supported by almost all file systems – Windows, Apple and Linux’s main distributions known as distros. So it is a very “universal” format and is handy to use between various computers new and old mostly using Flash Drives and memory cards e.g. SD cards.
2. NTFS as described above is the norm for all Windows Operating Systems and was introduced in July 1993 and has a file size limitation of 16 exabytes (EB) which is 1 million TB (Terabytes). In addition to the file size NTFS also supports Journaling to avoid corruption, supports file permissions and encryption and any modern Windows OS needs to be installed on an NTFS drive. Apple computers can read NTFS drives but cannot write to them and the same is true for older Linux computers.
3. exFAT is a newer format which is extensible File Allocation Table and introduced by Microsoft in 2006 for use with large capacity USB Flash Drives and memory cards (anything over 32GB basically). In a Windows environment, the maximum file size is 16EB and has been adopted by SD Card Association (SDXC) as their default format. Apple computers and newer Android devices can read and write to exFAT. Linux computers may need extra drivers installed to access exFAT devices.
4. Ext4 and associated previous versions (ext, ext2 and ext3) are Linux based file systems and was first launched in 1992. In 2008 ext4 was released which as in the previous ext3 included journaling (see NTFS above) and is still the default Linux format for computer drives. File sizes of up to 16TB and volume size of 1EB are available. The ext4 is not supported by Windows computers nor by Apple computers natively.
5. HFS+ (OSX) and APFS (macOS) as mentioned above are the default for Apple computers. In 1998 HFS+ (or Extended) was released which included journaling with files and volumes up to 8EB from OSX 10.4 onwards. In 2017 Apple introduced APFS which is optimised for SSD drives. Both of these File Systems are not supported natively by Windows or Linux computers.
6. ZFS or Zed File System introduced in 2005 by Sun Microsystems and now developed by the OpenSolaris Project. This new File System integrates a volume manager to control storage hardware which provides increased data protection. Currently, OpenZFS is available for Linux, FreeBSD and other UNIX systems and maybe available in Windows and macOS in the future.

We trust that the above information regarding file systems has been of some assistance to you, remember if you live in Brisbane or surrounds and have a problem with your Mac, Desktop or Laptop we are open 6 days a week and always willing to help.

Author David
Technician
Affordable Computer Repairs and Service