Path: utzoo!attcan!uunet!convex!killer!osu-cis!tut.cis.ohio-state.edu!mailrus!ncar!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.periphs
Subject: Re: Megatape 8mm backup device
Message-ID: <14713@mimsy.UUCP>
Date: 24 Nov 88 02:34:30 GMT
References: <14650@mimsy.UUCP> <125900002@ishmael>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 28

In article <125900002@ishmael> cball@ishmael writes:
>Do the Megatape drives read after write to verify that the data written
>on the tape really made it? 

I do not know (and the manual is on its way back to Megatape, not that
I remember seeing anything about it there), but it is worth noting that
read-after-write is not a particularly good verifier: it does not check
for faults in data paths, controllers, caches, . . . .

>Now that you have 8mm drives will you use a mix of 1/2" and 8mm backups
>or will you do a wholesale switch to the new format?

(We do not have them yet!  That part is up to the money people.) Daily
(small) backups might still go on 1/2 inch tapes, but at $10 per tape
per full backup per machine (vs $400 per 20 tapes per full backup per
machine [really a WAG at an average]), and given that the 8mm
cartridges take much less space, we may just keep every backup ever
made, at least for some number of years.

>A related issue is how long you store backups and expect them to remain
>viable.

Minimum maximum of 5 years.  There is no reason that the 8mm tapes should
be any less permanent than 1/2 inch tapes, and some reason to expect them
to be more so.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris