> On Jun 27, 2019, at 8:21 AM, Warner Losh via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> Back when I got to school and I was hanging around the computer room on
> campus (back when it was THE room on campus with computers), I saw this
> half-dollar sized plastic fob on the desk and asked what it was for. The
> on-staff operator took a mag tape off the rack, opened it up and set the
> end of the tape on the table. She then took the fob and placed it on the
> end of the tape and all the iron filings that were suspended in the liquid
> inside the fob aligned to the magnetic fields of the tape.

I don't recall seeing one of those in either of the computer rooms I worked in 
as a student back in the late 1980s. I would love to get my hands on one (or 
make one?) now.

-- 
Mark J. Blair, NF6X <n...@nf6x.net>
http://www.nf6x.net/

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