Hard Drive Formats – Part Two – Evolution of File Formats

File Systems, beginning with the File Allocation Table (FAT), have evolved and have been joined by Microsoft’s NTFS (New Technology File System), ext2, and other methods to manage the map of your hard drive data.  In Part One, we took a very basic look at why a file system is needed on your drives.

Your hard drives – especially the newest ones – have trillions of areas onto which data can be recorded. FAT and NTFS are two of the most common file systems in use for defining and managing the location of every bit of data on your drives.  Both FAT and NTFS have evolved, with newer versions providing the ability to handle larger drives and, in the case of NTFS, also adding features.  The original FAT specification was limited to drives with a maximum capacity of 32 MB (that’s MEGABYTE, not Gigabyte).  The next iteration, FAT 16, had a 2 GB maximum limit.    These limits truly ARE limits because the number of bits in the FAT corresponds to the number of powers of 2 that can be used to describe the head and disk positioning.  For FAT 16, for example, there are only 2 to the 16th power available numbers to assign to the task.

Additionally, the file naming conventions grew along with the capabilities of these file systems.   Many of us still remember the old restrictions that DOS and early versions of Windows imposed on us, allowing us a total file name size of 8 characters, plus a three character extension.  For example, the name Aleratec.exe would have been okay, but Aleratec makes good products.exe wouldn’t.   Directory names with spaces weren’t allowed and the entire issue of file and directory (or folder) names was severely limited.  With the advent of FAT 32 and NTFS, such limitations were finally removed or minimized.

FAT 32 supports a maximum drive size limit of 8 TB.  At the rate that drive sizes continue to increase, and assuming that drive manufacturers overcome the significant issues involved in packing data into nearly sub-atomic sized spots on the platters, some believe that it should only be two or three years before the 8 TB limit is reached.

NTFS, supported primarily by Microsoft’s Windows and Windows Server Operating Systems, provides a variety of benefits over FAT 32.  These benefits include encryption, automatic compression, support for dynamic disks (which enables the system to use more than one disk on a machine as if it was one single, larger disk), and other features.  The size limit for drives with NTFS formatting has many years of headroom – a total of 16 exabytes.  (An Exabyte is 2 to the 60th power, or 10 to the 18th).   Compared to a Terabyte, which is 2 to the 40th power, it’s a HUGE number that will probably remain larger than hard drive makers would be able to manufacture – and that few organizations may soon need).

Other file systems have been developed for Linux.  These include ext2 and ext3 with a limit of 32 TB, ext4 with a 1 exabyte limit, Reiser FS with a 16 TB limit, and a number of other file systems.

The major issue with these file systems is their incompatibility with the other systems.  Although Microsoft provided a utility in some versions of Windows that enabled conversion of a FAT 32 drive to an NTFS format, while saving all the data and remapping the storage locations, there was no method to undo this once the change was made.

Mark Brownstein is a technology journalist and technology consultant who specializes in explaining and interpreting new technologies, and clarifying how to integrate these new products into current systems. He has been Editor-In-Chief at computer technology and networking publications, has held significant editorial positions at major technology magazines, and is a frequent contributor to various technology magazines. He has written seven books. He is Microsoft Certified, and spends much of his time testing hardware and software products, running his own networks, and learning the best ways to get computer systems running and to keep them running.

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