function TWMIPhysicalDriveListGetter.IsDriveSetValidType: Boolean;
begin
  result := (not VarIsNull(CurrentDrive.MediaType));
end;

function TWMIPhysicalDriveListGetter.IsDriveLoaded: Boolean;
begin
  result := (CurrentDrive.MediaLoaded);
end;

function TWMIPhysicalDriveListGetter.IsDriveSetValidID: Boolean;
begin
  result := (not VarIsNull(CurrentDrive.DeviceID));
end;

function TWMIPhysicalDriveListGetter.IsCurrentDriveAvailable: Boolean;
begin
  result :=
    IsDriveSetValidID and
    IsDriveLoaded and
    IsDriveSetValidType;
end;