Windows 9X fdisk and format Commands Report the Size of Hard Disk Drives Greater Than 64 GBytes Incorrectly
Last updated: 6/1/04

Q.  Why do Windows 9x fdisk and format commands executed at the DOS prompt report hard disk drives  that are larger than 64 GBytes as much small drives?

A.  "quig" reports that fdisk sees an IBM  82 GByte drive as just under 13 GBytes.  I have been having the same problem with 80 gig WD drives...  According to MSKB Q263044, the reason is that fdisk for:

Microsoft Windows 98 Second Edition
Microsoft Windows 98
Microsoft Windows 95

... uses some 16-bit values internally to calculate the size of the drive and some of the variables overflow when the drive size is equal to or larger than 64 GBytes.  According to MS fdisk reports the full size of drive that is greater than 64 GBytes as the actual size minus 64 GBytes.

Which in "quig's" case would be 18 GBytes and in mine 16 GBytes?  As I recall I was getting a little over 10 GBytes.  This download fixed the problem.

It will not work with 48-bit logical block addressing (LBA) hard disks, and it is not supported on hard disks larger than 137 GB.

Free FDSK works with larger drives and may be an easier solution.

My version (3.0) of Partition Magic reports it correctly.

Also, the same person probably wrote the fdisk and format programs because both programs have the same problem.  As reported in MSKB Q263045, the problem with format "is a display (or cosmetic) issue only; the drive is formatted to its full size."  There is no fix.  Also, the problem does not occur if the drive is formatted with the Windows Explorer.

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