topic DDS Tape problem in Operating System - HP-UX

DDS Tape problem

Kenny Chau — Fri, 07 Sep 2001 01:21:51 GMT

I had got a DDS tape and I am sure that the tape is NOT write-protected. However, when I type command "mt -f /dev/rmt/0m status", it shows that the tape is write-protected. Does anyone know how to unprotect the tape??

Thanks.

Re: DDS Tape problem

Sridhar Bhaskarla — Fri, 07 Sep 2001 02:59:18 GMT

Kenny there is a slit at the bottom of the tape. It should be covered to write to the tape. Make sure the tab is not in lock position.If this doesn't work, try with another tape to isolate the problem.

-Sri

Re: DDS Tape problem

Kenny Chau — Fri, 07 Sep 2001 03:02:30 GMT

Thanks Sri, I am sure that the tape is no problem with the slit. I had tried to use another tape but the new tape is problem free that it did not show write protected. Do you have any clue about this?

Thanks.

Re: DDS Tape problem

Michael Tully — Fri, 07 Sep 2001 03:09:49 GMT

Hi,

The tape iteself is either faulty or the slot where you write-protect is broken. Through the tape or away or make a copy before doing so.

HTH
-Michael

Re: DDS Tape problem

Sridhar Bhaskarla — Fri, 07 Sep 2001 05:21:02 GMT

Kenny,

Obviously it looks like a problem with the tape. I appreciate you trying to be cost effective to your company :-)

-Sri

Re: DDS Tape problem

Gregory Fruth — Fri, 07 Sep 2001 21:19:20 GMT

Perhaps the tape is in a DDS format that your drive
can read but not write; e.g. the tape is DDS-1
(90 meters) but your drive is DDS-4 (150 meters).

From:
http://www.products.storage.hp.com/eprise/main/storage/DisplayPages/faq.htm?DataPage=tapes-dds

Why is my backup application reporting this tape as "write
protected" when the write protect tab is in write-enabled mode?

Most DDS-1 and all DDS-2 and DDS-3 drives use a method
called the Media Recognition System (MRS) to detect when
qualified DDS media is being used. If you try to use a non-MRS
data cartridge, you will only be able to read from it, not write
to it.

Re: DDS Tape problem

Kenny Chau — Tue, 11 Sep 2001 02:48:41 GMT

Thanks Gregory, but how can I tell that the tape is in correct format? I can only see that the tape is a DDS tape but don't know that it is DDS-1 / DDS-2 / DDS-3 format.(the tape is old tape that without any label on it).

Thanks.

Re: DDS Tape problem

Patrick Wallek — Tue, 11 Sep 2001 03:03:35 GMT

The tape should have written on it somewhere either DDS, DDS2 or DDS3. If it does not have that then it should have something about the length somewhere. Something like 60, 90, 120 or 125. If it says 60 or 90 then it is DDS. 120 is DDS2 and 125 is DDS3.

Re: DDS Tape problem

Kenny Chau — Tue, 11 Sep 2001 03:09:55 GMT

It had a 60m word on the tape. So I think it is DDS-1 tape. However, I am using DDS-3 tape drive. So is it impossible to write data to this DDS-1 tape with my DDS-3 tape drive??
I had used other DDS-1 tape (2.6GB and 4GB) and it is successfully read and write. So is that the tape problem?

Thanks.

Re: DDS Tape problem

Patrick Wallek — Tue, 11 Sep 2001 03:19:49 GMT

60m is an original DDS tape.

You should be able to write to a 60m with a DDS3 drive.

Have you tried cleaning the drive? You might try running a cleaning cartridge through the drive 2 or 3 times.

It you still can't write to the tape, then it probably is a problem with the tape itself.

Re: DDS Tape problem

Animesh Chakraborty — Tue, 11 Sep 2001 04:29:21 GMT

hi ,
Try that faulty tape in another drive(if u got one),if it doesn't work then ask someone to throw it for you.

Thanks
Animesh

Re: DDS Tape problem

Gregory Fruth — Thu, 13 Sep 2001 17:16:49 GMT

I agree, it sounds like the tape itself is bad.

For DDS-4 owners, I have noticed that the
media compatibility appears to be different
depending on the manufacturer. HP's
SureStore 40 DDS-4 drive can read
and write DDS-2, -3 and -4 tapes and
can read DDS-1 90 m, but cannot read
or write DDS-1 (60 m).

On the other hand, Sony's web site states
that their DDS-4 drives can read and write
DDS-1 through 4 (though they doesn't say if
they mean DDS-1 60m or 90m).

Just FYI

Re: DDS Tape problem

Carlos Fernandez Riera — Fri, 14 Sep 2001 08:10:32 GMT

Perhaps that faulty 60m tape is a DAT tape and not DDS tape.

If the the tape is not MRS, maybe this is the problem.
Now, how to be sure if it is MRS?

take the tape on your hands and open the slide, pressing both small blockers and push the slide. Now open the cap and rewind tape manualy to begging of tape. At the begging may be some strips, this is MRS. If you cant see that stripes it is not MRS.

Re: DDS Tape problem

Kenny Chau — Fri, 14 Sep 2001 08:29:46 GMT

Thanks Carlos, you are right, there is no stripes at the beginning of the tape. So is it a MRS tape? That's mean I can not read the MRS tape from the DDS tape drive?? But the label shows that it is a DDS tape. Any clue about this??

Thanks.

Re: DDS Tape problem

Carlos Fernandez Riera — Fri, 14 Sep 2001 08:51:49 GMT

MRS is newer that DDS. DDS-1 could be MRS or not MRS; DDS2, DDS3 and DDS4 are all MRS.

No strips is not MRS, and these is the problem,

I gess you can read tape but not write on it.

If you cant read tape, i can tell you more intructions.

Maybe i not explain it good before.

Re: DDS Tape problem

Bill Hassell — Fri, 14 Sep 2001 11:22:33 GMT

For everyone:

60 meter tapes are DAT tapes (and not to be confused with DDS tapes) and while they use the same external case and tape size, the media was never designed to store computer data. The very first DDS drives would read and write to anything that would fit into the slot (60 or 90 meters). This was before the days of Media Recognition System where little holes were punched in the leader to identify the type of tape.

The reason for MRS is that DDS technology was emerging rapidly and as tapes got thinner and the stiffness and composition of the magnetic coating changed, it was highly likely that new, high density tapes would jam in the older drives. SO MRS would only allow tapes designed for the drive to be inserted. A DDS-3 tape is popped right back out from a DDS-2 drive as an example.

Since 60 meter tapes may have been used n the past (and DAT tapes have VERY HIGH error rates), firmware in DDS drives was changed to always treat 60 meter (non-MRS) tapes as always write protected. You don't want to EVER use DAT tapes for computer data.

True Digital Audio Tapes have extensive error correction to accomodate the error rate but also include a fill-in the gaps technique which works fine on music (a few milliseconds of lost data is replaced by the same information from a previous record), but is catastrophic for computer data.

So, read all your 60 meter tapes and capture the information onto DDS tapes, then discard them. It is also a good idea to use the term DDS rather than DAT since they are not the same.

Re: DDS Tape problem

Carlos Fernandez Riera — Fri, 14 Sep 2001 11:44:33 GMT

Bill:

To be true i have in my hand a 60m DDS-MRS tape from HP. This type of tapes are not very usual, but it is posible to buy ( or it was posible to buy).

Copy data on older tapes to new formats is a very good idea.

You can see more information on problems whit oldest tapes on:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x171172106351d5118fef0090279cd0f9,00.html

Regards.

Re: DDS Tape problem

Kenny Chau — Mon, 17 Sep 2001 02:49:25 GMT

Thank all of you very much. I think this is the problem why I hit write protect error even I am sure that the tape is write enabled.