This article was previously published under Q269600
This article has been archived. It is offered "as is" and will no longer be updated.
When you use some models of Hewlett-Packard SureStore 4-mm digital audio tape (DAT) drives on a Windows 2000-based computer, Removable Storage recognizes the drive, but does not recognize any media in the drive even after you perform a full inventory.
Because Removable Storage does not recognize the media, the "4MM DDS" media pools may not be created under the free, import, or unrecognized system pools.
This problem prevents you from preparing new media, reading a tape, or writing to an existing tape.
NOTE: Ntbackup reports the following error messages when attempting to backup for the first time:
There is no unused media available with the selected type.
Add unused media or click cancel to select another type.
This problem usually occurs on computers with large amounts of physical memory. Some Hewlett-Packard (HP) tape drive models can create a report when the drive is dirty and requires cleaning. The Windows 2000 4mmdat.sys driver erroneously senses a status code that the drive is dirty when it is not, and this prevents media from being read.
To help determine if this is the problem that you are experiencing, watch the tape activity light on the tape drive and monitor the Removable Storage work queue while you perform a full inventory against the drive. If the Removable Storage work queue shows that the Inventory and the Identify New Media procedures have finished quickly, and the light on the tape drive never flashes, use the steps in the "Resolution" section to correct the problem.
To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
You can incrementally reduce computer memory until the tape drive works bymodifying the Boot.ini entry that is used to boot the computer, and then adding a /maxmem switch, or you can use a different model tape drive.
The following example shows a modified Boot.ini file that is using 128 MB of random access memory (RAM):