ADSM-L

Re: LTO drive cleaning in a 3583...

2005-11-12 09:03:40
Subject: Re: LTO drive cleaning in a 3583...
From: Richard Sims <rbs AT BU DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Sat, 12 Nov 2005 08:59:32 -0500
LTO "drive" cleaning is two phase: self head cleaning; and, if
thereafter warranted, cleaning tape utilization. Self cleaning
employs a brush to dislodge micro contaminants from the head. Being
an open standard, LTO affords participating vendors full flexibility
in designing internal cleaning mechanisms. According to interesting
whitepaper http://www.overlandstorage.com/whitepapers/
Super_Drive_wp.pdf , IBM's drive performs a single swipe across the
head as a tape is loaded and unloaded, where the brush is attached to
an arm involved in the tape load/unload process. Other vendors employ
a more vigorous and allegedly more thorough self cleaning process, as
described in that paper and in the more detailed paper http://
www.overlandstorage.com/whitepapers/LTO_Cleaning_wp.pdf .
Incorporating "canyons" into the head design greatly helps trap and
isolate debris. (Standard caveat: vendor designs are subject to change.)

As a trained mechanical engineer, I'd really like to know where all
the removed debris goes over time. Some of it is certainly going to
cling to the brush (especially, stringy dust particles); and most of
it is going to either fall to some area below the brush or be
propelled to various parts of the drive via the brushing action.
Whereas tape drives are open to the atmosphere anyway, the detached
particles are of little additional concern. The stuff which
accumulates on the brush is what would concern me, as  it tends to re-
contaminate the head and possibly abrade it. The cumulative customer
experience with LTO certainly seems to demonstrate, however, that it
is extremely effective at dealing with contaminants such that the
head-tape interface remains highly reliable.

   Richard Sims

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