Advice on change of tape drive please.
Bill Codding
peda at simplicity.Stanford.EDU
Wed Nov 28 17:39:44 AEST 1990
Judging by the amount of mail I got from my reference to my
post on 3M tapes and interchangeability, the original post
never got through. Here it is again. Please let me know if
this gets out.
---Copy of original post follows---
In article <OPERATOR.90Nov20104952 at expya.cs.exeter.ac.uk> operator at cs.exeter.ac.uk (Sue Charles) writes:
We at the moment have a QIC-11 tape drive on our sun and are backing up
onto 3M DC300A -300ft Tapes
DC300XL/P 450ft Tapes
DC600A 600ft Tapes using the maximum tape capacity.
In the new year we will be installing a QIC-150 drive.
Which (if any) of the above tapes would I still be able to use
If you want some really confusing, conflicting information on this
subject, call the 3M hotline. Want to be more confused? Call the
drive manufacturer.
We had similar questions. After what amounts to several
hours of experiments and being on the phone with the above goons,
the following information finally falls out.
1) Using our Archive 2150S QIC-150 drive (Stellar GS1000), we can
read AND write QIC-150, read ONLY QIC-24, and neither read NOR write
QIC-11.
2) Our Sun-3 was able to write both QIC-11 (nrst0) and QIC-24 (nrst8).
Only the higher density is readable in the QIC-150 drive. I believe
Sun-2's only wrote QIC-11.
3) 3M said you should not use more than one type of tape in a drive,
as the heads "wear in" to one type; using another can cause reliability
problems.
a) 3M explicitly said to not combine DC600A's and DC300XL/P's
on one drive. Upon pressing them for details, however, the two seem
to be the same form factor, same thickness vinyl, just a different
coating/oersted rating. I find it hard to believe you cant mix
different _coatings_ in your drive.... Archive says it is OK to
read the occasional DC300XL/P in your QIC-150 drive, though.
b) Archive says you can use either DC600A or DC6150 on their QIC-150.
They say the physical medium is the same, so no wear problems. However,
the 6150 has an additional capstan (roller) and a wider opening in the
plastic housing. The tape identification marks tell the tape drive
to write more tracks on the 6150, since the housing hole allows more head
clearance. Thus, 120MB on a 600A, and 150MB on a 6150.
c) The 6150 is actually Archive's recommended tape for the QIC-150; the
600A was originally designed for a lower capacity drive (hence the "60MB"
marking on the case) but will work writing fewer tracks.
d) Archive says you cannot interchange [DC6150/DC600A] and the DC6250.
The 6250 is thinner tape, and causes the head to wear more (or less??)
"convex-ly".
4) 3M sometimes gives different MB ratings to tapes which have the same form
factor, coating, thickness, etc; the only difference being that they
are marketed for use on drives which write different numbers of tracks!
Whatta waste of brain space. This isn't even my job.
I'm charging them $10,000,000 for my time.
------------------------------------------------------------------------
Bill Codding (415)493-3554 (w)
Research Engineer (415)751-5484 (h)
P.E.D.A. peda at simplicity.Stanford.EDU
------------------------------------------------------------------------
More information about the Comp.unix.admin
mailing list