【Hitachi】 H-8488-1 Open Reel Magnetic Tape Unit

The H-8488-1 was an open reel magnetic tape unit which achieved a recording density of 6250BPI by using GCR (Group Coded Recording). It was developed as a magnetic tape unit in the HITAC M Series, and shipped in May 1976.
In addition to improved recording density, the inter block gap (IBG) was halved, thereby dramatically improving the memory capacity of each magnetic tape reel to about 160Mbyte (4 times the previous value) and helping to reduce the number of backup tapes.
This high recording density was achieved because it was possible to suppress the increase in magnetization reversal density on the tape, despite the increase in information recording density using the GCR system. That is, a magnetization reversal density of 3200 times/inch was necessary to record information at a rate of 1600 characters per inch, as in the system used with the previous 1600BPI model, but with the GCR system, the number of magnetization reversals was 9042 max.., while information was recorded at 6250 characters per inch.
This unit was developed together with the H-8487-1, which had a different tape speed. This family was the first series of Hitachi magnetic tape units shipped overseas and used throughout the world.