4 Nov
2025
4 Nov
'25
7:53 a.m.
---------- Forwarded message ----------
From: Paul Koning <paulkoning(a)comcast.net>
To: "cctalk(a)classiccmp.org" <cctalk(a)classiccmp.org>
Cc:
Bcc:
Date: Sun, 2 Nov 2025 14:43:49 -0500
Subject: [cctalk] Re: How hard would it be to make new dec tape media?
10-20 years ago I had a good Point-of-Contact (POC) at 3M (before we both
retired). I asked him whether they still (at that time) made DECtape media
and was told that 3M had sold their magnetic media operations to another
company who also got out of the business before I contacted them. I also
asked my POC (and the contact at the other company) if any DECtape media
had been kept in a warehouse or similar -- he checked 3M's inventory system
and told me that they had no record of any remaining DECtape media. The
other company's contact had a similar "you've struck out" story.
Bob
P.S. I thought that I read here or in a PDP-8-specific forum/mail-list
that DECtape wasn't actually laminated on both sides, which apparently
explained the visible red oxide material removed from dirty DECtapes while
cleaning them (per whoever posted their observations)?
On Nov 2, 2025, at 10:46 AM, Jon Elson via cctalk
<cctalk(a)classiccmp.org>
wrote:
On 11/1/25 20:49, ben via cctalk wrote:
years ago, we made working replacements from 3/4" instrumentation tape, but
it was NOT laminated. It had a print-through issue where if left sitting
for a few months, it would start getting errors. I have no idea if there
is anywhere you can buy 3/4" instrumentation tape. Maybe you can get 3/4"
video tape.
Bitsavers has the 3M spec for 480 and 481 sandwich tape, I'm not sure
which of these two is what DEC used. It seems crazy, but it can't hurt to
ask 3M if they still make that stuff.
paul
How hard would it be to make new dec tape media?
60 year tape could use a replacement.
Ben.
DecTape is laminated, ie. it has Mylar on both sides of the oxide. 50