AIT is a helical scan medium, as are DAT, VXA and Exabyte. As with other helical scan formats the most common problems involve failures within the drive mechanism when the tape is loaded resulting in creasing, stretching or snapping of the media, or mis-recording the data on the tape.
Logical problems relating to overwriting, data corruption and externally caused damage from fire, smoke or water have also been successfully dealt with.
Common Problems
- The AIT loads noisily, all the drive lights flash and no data can be read.
- The restore process fails with an AIT tape media flaw.
- Data transfer is seen to stop and you can hear fast tape motion.
- The AIT tape drive lights constantly but the tape will not eject.
- The AIT is reported as being blank.
- Beneath the tape shutter, no tape is visible or the tape is badly creased.
This is not an exhaustive list but covers the broad range of situations where Altirium have been able to provide successful data recovery services.
Unable to read data. All three lights on the front of the drive flash simultaneously.
The AIT drive has failed to read data from the tape's system area, and the tape's partition information. This could be a problem with the drive, with the media or with the recorded information. The most important thing immediately is that if you decide to test the drive with other tapes to see if it is working properly, don't use a valuable system backup as you could wind up needing a data recovery from two tapes.
If the drive is working then the fault is tape related. The most likely cause is physical damage caused by a problem with the drive that made the recording, or a cartridge mechanism problem during the unloading of the AIT cartridge. This is why you need to be very careful about checking the drive operation, we have seen cases where several vital tapes have been damaged by people testing the drive before deciding it is definitely at fault and then realising that they need a data recovery or seven.
Check the media by (very carefully, and do not touch the tape) lifting the shutter and having a look. If there are no signs of damage then it could be worth trying the tape in a different drive. If there is any sign of damage then the only option is to go down the tape data recovery route.
The restore process fails with an AIT tape media flaw.
This could be the drive or the tape at fault. Presuming that the drive is fine (see the previous paragraph about checking this very carefully), and you have run a cleaning tape through the drive then it is worth retrying the operation. You need to be confident that there is no physical damage within the cartridge as repeated attempts to read data from the AIT could then result in the damage being made worse, even with the tape snapping and becoming mangled within the drive mechanism.
It is possible that a selective restore of the most vital data might avoid the area of the problem and could be worth a try, otherwise it’s data recovery time.
Data transfer is seen to stop and you can hear fast tape motion.
The AIT drive has failed to read data from the tape, is presuming that oxide from the tape has caused "head-clog", and is attempting to clear the heads by running tape, and then it will re-position to re-try reading. We have seen tapes where this happens repeatedly during reading, but the process is successful (though taking several times longer than usual). There is a strong possibility that the restore process will fail with a medium error.
The problem sometimes relates to tracking, either drive reading the tape or the one that made the recording could have a mis-aligned tape guidance mechanism causing the tape to incorrectly position relative to the heads. If this is the problem, rather than damage, then re-attempting the read might work on short selective restores.
The three lights on the front of the AIT keep flashing but the tape will not eject.
The drive is trying to load the AIT cartridge, but failing to access data. Worse still it appears to be locked in a loop and will not respond to attempts to eject the tape. Our experience has been that the drive will stay in this state for a long time (we've seen many instance where the AIT drive never recovers from this condition).
There are ways to force eject an AIT but this requires that the drive be dismantled and manually ejected using a small screwdriver to rotate one of the screws in the load assembly. An added complication is that the tape is loaded and held within the tape guidance mechanism, and the manual unload process might well not clear the tape and so it will be snagged during ejection and be damaged.
If you get the tape to unload and it transpires that the problem is with the drive then a new drive should get you back running again. Otherwise there is a problem with the tape and a tape recovery is the only option.
The AIT is reported as being blank or containing no data sets.
If you are sure that you have the right tape, and that a successful backup had been made to it then the media has either been erased or re-initialised.
Erasure in a modern helical scan drive is not a magnetic wiping process but an over-recording of data with an internal pattern. Usually people do not want to wait the 3 hours it takes for a full erase, and opt for a quick erase which affects only the start of the tape. The majority of the data will still be present on the tape, though inaccessible. Gaining access to the data will require a tape data recovery service but at least not all is lost.
If the tape has been re-initialised, or re-labelled, then the situation is the same as for a quick erase and only a small amount of data will have been lost.
You have lifted the shutter and can see damage to the tape, or there is no tape visible.
If there is damage then the tape should not be put in a drive as there is a risk of it becoming stuck in the drive, or damaged further, and no chance of reading data. One minor crease close to the start probably won’t case a problem itself, but if there is visible damage when you look under the shutter it is almost certain that there is damage further along the tape where there is data stored.
If no tape is visible then the tape has snapped or become de-spooled. It takes a lot of force to de-spool an AIT as the media is fixed to each reel, the most likely cause is the tape being snagged by the drive mechanism during an unload, so you need to check your drive.
