Help on tape drive interoperability/reliability

[Carlos G. Mendioroz]

chip at chinacat.Unicom.COM (Chip Rosenthal) writes:

>In article <1990Nov20.000121.23207 at ico.isc.com>
>	rcd at ico.isc.com (Dick Dunn) writes:
>>rajs at hpindda.cup.hp.com (Rajeev Seth) writes:
>>> Everex tech support told me that it is not good enough that two different
>>> tape drives/machines read/write QIC-24 because the controller card for the
>>> drive has some security PAL chip [...]
>>Not only do we not find it to be true with other brand drives; I barely
>>find it believable.

>Of course not.  If they did that, it wouldn't be QIC-24 anymore!

>I think the confusion might be that Bell Tech used to OEM somebody's tape
>controller card (Everex?) and there was a PAL which prevented the adapters
>and drives from being interchanged.

And if they did that, it would't be QIC-02 anymore...

I think that the PAL's referred are those locating the control regs
of the controller. That way a driver for one card can't be used with
another card. E.G. wangtek PC-36 controllers have two control regs
one at adddress X (selectable) and the other at X+1.
Some dealers change PAL's to bring that to X+2...