Customers who buy Windows 95 PCs this fall will be able to maximize their hard disk space with a new FAT system, but the improved file handling may mean that existing utilities won't work until third-party vendors catch up.
Microsoft has updated the Windows 95 File Allocation Table (FAT) to 32 bits. The change will mean that less disk space will be wasted for PCs with 2GB-plus hard drives and that users will get more storage space for the same price, said Alec Suanders, a product manager at Microsoft.
FAT is the system used by DOS, Windows 3.1, and Windows 95 to manage the disk space used to store files. It organizes data into units on the disk called "clusters," and each cluster can store no more than one file. If a file doesn't fill a whole cluster, the rest of that space is wasted. For example, the existing FAT system can waste as much as 156MB on a 2GB drive, according to a white paper from hard disk utility vendor PowerQuest.
The current FAT version organizes files in 32K clusters, while FAT32 will use a minimum cluster size of 4K. This means that a 3K file wastes only 1K of disk space, instead of 29K.
But for the time being, Microsoft's improved FAT32 systems means that disk compression and defragmentation programs such as Symantec's Norton Utilities won't be able to read new file entries because they rely on the current 16-bit FAT systems.
Microsoft maintains that relatively few users will be affected by the change because it intends to ship FAT32 only to OEM hardware manufacturers and will not sell the system as a retail software product. Only purchasers of new computers will get the new system.
"The vast majority of customers will not be affected by this because [Windows 95 with FAT32] is only going out in an OEM release," Saunders said. "You'll have to buy a new PC to get this. It solves a problem for very large hard disks. It won't have a dramatic affect with disks smaller than 2 gigs."
Although users of the FAT32 systems still have to worry about conflicts with their existing utilities programs, most utility vendors will probably upgrade their software to support the new file system. Symantec representatives, for example, confirmed that the company will offer a new FAT32-compatible version of Norton Utilities but did not indicate whether users will be able to upgrade for free.
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