【Hitachi】 H-8523 High-Capacity Memory System

This unit was developed to meet the need for automation, improved space efficiency and lower price for peripheral equipment, and was commercialized in 1979 for use with the HITAC M Series.
This was a completely new memory system enabling storage ranging from 35GB (gigabytes) in the smallest configuration to 236GB in the largest configuration. The memory media was magnetic tape cartridges with a capacity of 50MB (megabytes) each.
The main features were as follows:

  • Automatic loading of media (Automated handling of magnetic tape cartridges stored in storage case)
  • Automation of file management (Mechanization of centralized management of data)
  • Random access to large volumes of data (Introduced concept of a virtual memory device)
  • Reduced memory cost (Achieved a bit cost close to magnetic tape combined with random access capability)
  • High-reliability design (Employed duplication of hardware and new error correction theory)

Specifications of H-8523 High-Capacity Storage System
Equipment model name H-8523 High-Capacity Storage System
Completion date 1979
Max. memory capacity 35GB–236GB (*1)
Max. number of stored cartridges 706–4,720 (*1)
Data transfer speed 874 KB/s(Instantaneous max.)/ 371 KB/s(Effective)
Access time Stripe search time : 11 msec–13s
Load/unload time: Approx. 5s
Cartridge movement time: 2.6 s-7.6 s
Equipment external dimensions Width :4,623mm–9,186mm (*1)
Depth:810mm Height:1,915mm
Data cartridge Type of recording media Magnetic tape (Housed in cylindrical cartridge)
Memory capacity 50.4MB/cartridge
Recording density Equivalent to 7,023BPI
Recording system ZM modulation system
Tape dimensions Width:68.6mm
External dimensions Height:102mm
Connected systems HITAC-M Series

*1: The max.imum number varies depending on the equipment configuration.

Appearance of the H-8523 High-Capacity Memory SystemAccessor part of the H-8523 High-Capacity Memory System