Look at http://www.tapeheads.net/showthread.php?t=39958
Marc On Thu, Jun 27, 2019 at 8:30 AM Mark J. Blair via cctalk < cctalk@classiccmp.org> wrote: > > > > 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/ > >
