UPDATE: Ed, I just read the earlier messages and saw that the windows getvolumeinformation api is returning the same serial number for different logical drives on the same hard disk. I never noticed this before in my Delphi code--I'll have to test that tonight! :0(
Tracy

SNIP
>You could do it with a bit more trouble in Delphi or VB6 or later, but they have real strong datatyping and structures and pointers and unions, oh my!

Actually, I wouldn't do it that way at all in Delphi. Delphi has a function: GetMediaID that will examine a disk's serial number. GetMediaID is a wrapper around the Windows GetVolumeInformation API call.

Wouldn't something like the below Delphi code be useful in VFP?

var
  ID : MediaIDType;
begin
  GetMediaID2('C', ID);
  ListBox1.Items.Add('Volume Label = ' + 
    StrPas(ID.VolumeLabel));
  ListBox1.Items.Add('File System = ' + 
    StrPas(ID.FileSystemID));
  ListBox1.Items.Add('Serial Number = ' +
    IntToStr(ID.SerialNumber));

Actually, shouldn't the Windows Getvolumeinformation return the same information?

Tracy