22 Mar
2012
22 Mar
'12
4:36 a.m.
Yeah which is why they always taught the FEs to stuff their tie down their shirt when
servicing the old 3420s ;-)
-----Original Message-----
From: Dave McGuire <mcguire at neurotica.com>
Sender: cctalk-bounces at classiccmp.org
Date: Thu, 22 Mar 2012 04:14:54
To: General Discussion On-Topic and Off-Topic Posts<cctalk at classiccmp.org>
Reply-To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Pertec interface tape drive
On 03/21/2012 10:30 PM, Adrian Stoness wrote:
yea pretty much i dunno much about tape first time be
dealing with one.
No worries...Tape like this is generally pretty simple to deal with;
we'll help you out. What make/model drive is it? Can you get some pics
of the back, especially the cabling? There are two most common types of
tape interfaces, three-connector ("unformatted") and two-connector
("formatted") Pertec interfaces. It's likely your drive has one of
those two types.
Next...9-track drives' recording density is specified in "BPI", or
Bits Per Inch. Common densities are 800, 1600, and 6250BPI. Also seen
from time to time is 3200BPI, but that's much less
common.
There are three main sizes of reels; 600', 1200' and 2400'. I've
seen farm more 600' and 2400' than 1200', but you'll see all three
floating around. There may be other sizes but they're not very common.
There are three main types of tape handling mechanisms. Going from
least desirable to most desirable, and also the easiest to the hardest
to maintain, they are tension arm, air bearing, and vacuum column.
Tension arm uses one or two long (4-8") arms with a roller on one end
and a pivot on the other, and it moves back and forth to essentially
"hold" a length of tape off the reel. Air bearing mechanisms have
smooth curved surfaces with lots of little holes punched in them that
are pressurized from behind by a blower. The tape rarely if ever
touches the surfaces of these curved pieces, reducing friction (and
therefore tape wear) considerably. Vacuum column drives are more
complex; they use a vacuum pump and (usually) two vertical columns that
hold a dangling "loop" of tape and have a servomechanism to rotate the
reels just the right amounts to keep the loop position constant, while a
roller moves the tape across the head to the desired position. There's
very little friction in this type of system. They can be, however,
pretty tough to maintain.
Let's find out what you've got first.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA