norm@fluke.UUCP (Norm Seethoff) (03/17/84)
We have 3 TU77 tape drives and one TU78, each on a different system. Since December, we have been plagued by tape damage inflicted by the tape drives. It first showed up on the TU78, and later showed up on the three TU77s. Symptoms vary from neat folds across the width of the tape beyond the load point, to scratches on both sides of the load point, to folded leaders inflicted by the autoload mechanism. The nature of this problem is serious, since from direct experience I have seen the results of the TU78 mangling a level 0 dump tape that we were using to rebuild a reformatted disk. Think about this for a moment. We can not tell for certain if the damage beyond the load point is inflicted on the rewind/unload sequence after the tape has been written, or on the load/forwardspace/rewind sequence when a tape is loaded for reading. We have absolutely NO confidence in the integrity of the tapes written on these four systems. Worse yet, we don't feel secure in running a read/verify pass on the tapes for fear that the drive will mangle the tape then. All four drives have been on maintenance by DEC since the day they were installed. The problems were first noticed in December. The oldest of the drives has been in use for two years. The frequency of known tape mangling is in the range of 2 to 5%. DEC Field Service now seems like a fixture around our tape drives trying to fix the problem. Has anyone else seen this type of problem? Better yet, has anyone found a way to solve it? Any pointers towards a solution would be greatly appreciated by everyone in our Department. Norm Seethoff Technical Computing John Fluke Mfg. Co., Inc. (206) 356-5054 decvax!microsof!fluke!norm lbl-csam!fluke!norm uw-beaver!fluke!norm