UDF is known as a file system for DVDs. But very few people know that hard disk drives can also be formatted as UDF. A UDF- formatted HDD can be read by Windows 98 and Windows XP without any special drivers, Windows Explorer seems to work fine with it.

A special file system driver by SAI allows to read and write UDF-formatted HDDs under Win98 and WinXP.

The UDF file system allows theoretically very large file sizes, and it is not Microsoft, but open. A UDF-formatted HDD can be set from read-write to read-only by turning off the special file system driver.

I have attached 3 screenshots of the properties sheet of a UDF-formatted 80 GB HDD, under Win98 and WinXP. Under Win98 the UDF-formatted HDD has 2 drive letter (one is not accessible) when the special file system driver is active, but only 1 drive letter when the MS read-only driver is active. Under WinXP a UDF-formatted HDD has always a single drive letter, regardless of the driver.

SAI refers in their documentation to CDs and DVDs, not to HDDs. UDF-formatted HDDs seem to be uncharted territory under Win98. There are very few software tools for UDF-formatted HDDs. Acronis Disk Director Suite 10.0, for example, displays "File system error: Invalid format", Norton Disk Doctor displays "Unable to read from drive J:" and ScanDisk "cannot check this drive because there is no disk in it, it is not formatted or a disk utility has locked it".

Are there tools to handle UDF-formatted HDDs? Are there any horror stories about them? Does anybody have any experience with them? What are the benefits or disadvantages of a UDF-formatted HDD vs NTFS or FAT32? Could there be any special uses? Win98 Explorer has a major problem with file deletes when IE6 is installed - but maybe there is no such problem on a UDF-formatted HDD? Maybe some bugs of Win98 occur only on FAT/FAT32 partitions, but not on a UDF-formatted HDD? I seem to come across multiple-drive-letter problems quite regularly, do they occur also with a UDF-formatted HDD, which can have only one partition? Can USB sticks and SDHC card be formatted as UDF and be read and written to under Win98? Any ideas and suggestions about UDF-formatted HDDs are welcome.Click to view attachment

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http://en.wikipedia.org/wiki/Universal_Disk_Format

Advantages over NTFS:
- No journaling - better performance
- no trouble with permissions
- Acessible with multiple operating systems

Advantages over FAT32:
- Can handle bigger files

Windows 98 can work with version 1.02.

Since its behaviour is something that has not been tested yet with harddisks it might be interesting. I use UDF for DVDs and videocapturing. It is just a question how can other applications handle different filesystem. Generally there should be no trouble.

Is there any disk tool available, such as scandisk or chkdsk to scan the drive for errors?
And what exact method you have used for formatting?

http://homepage.mac.com/wenguangwang/myhome/udf.html