PT-3 tape

These tapes were used to store data for mainframe computers. In Poland they were made by Stilon factory, which made other magnetic media too - even floppy disks.

PT-3 Tape  
Manufactured by: Stilon, Pyral

Type: Magnetic media
Capacity: 4-16MB?
PT-3 was common tape storage device used with Odra 13xx computers. It was connected by serial channel and allowed theoretical maximum 96kb/s transfer speed.
Capacity of one reel varied, there were few sizes of reels and few densities allowing to store 8-16MB of data on large reel. Theoretically it was possible to put  more, but poor quality of tapes caused many errors.
PT-3 used 2 vacuum chambers to compensate reel inertia and keep the fragile tape in one piece during quick spin direction changes.

  Here are some photos from catalogues and magazines:
PT-3 units with tapes Tape in protectove cover PT-3 head


Tape library Datasaab similar unit Odra 1305 with PT-3 units (source: IKS, 1987)


General diagram Tape library and ICL-9000 computer in Statistical Office in Poland (Source: IKS, 1987)

Another interesting photo: Facit Carousel - device consists of 64 replaceable drums, each wound with magnetic tape. It's used as storage and temporary memory.