Hitachi HITAC 8800

These boards are from Hitachi HITAC 8800 computer that started its operation at The University of Tokyo Computer Center on January 1973 [1]. According to the report, the main memory of the system was 3 Megabytes in size, and was shared among two HITAC 8800 and two HITAC 8700 systems. Four disk systems, each with capacity of 233 MBytes are connected to the system.

The user-mode instruction set architecture of the HITAC 8800 and 8700 is compatible with the IBM System 360 [2]. However, the 8800 and 8700 supports virtual memory and shared-memory multiprocessing with sort of page-granularity directory-based coherent cache [3].

Plugin modules

Following modules are referred to as plugins in [3]. Two PCBs are connected using silver coaxial cables. Patterns on PCBs are laid out in a way that is similar to IBM 5110's.

Boardset 1

All these board-sets are unidentified.
Hitachi HITAC 8800 board (top board of set 1) pin side on top board of set 1
bottom board of set 1 backplane connector Hitachi HITAC 8800 board
Hitachi HITAC 8800 board Hitachi HITAC 8800 board

Boardset 2

Second unidentified boardset.
Hitachi HITAC 8800 board Hitachi HITAC 8800 board

Look at the way pins are coming out from chips. Pins are only on the edges of the package, contrary to IBM's packaging of the era.
Hitachi HITAC 8800 board

Boardset 3

Hitachi HITAC 8800 board Hitachi HITAC 8800 board

Boardset 4

Hitachi HITAC 8800 board Hitachi HITAC 8800 board

Last board

Hitachi HITAC 8800 board

Single-slot modules

Identity of these modules are not documented in literature.
Hitachi HITAC 8800 board Hitachi HITAC 8800 board Hitachi HITAC 8800 board

Double-slot modules

Identity of following modules are also undocumented. Could be from other kind of Hitachi computer.
Hitachi HITAC 8800 board Hitachi HITAC 8800 board

References

  1. Haruhisa Ishida, Masanori Oyama and Isao Ono: Computer Utility System at the University of Tokyo Computer Centre. 日立評論. Vol.55 No.11. November 1973. 日立評論社. 日立印刷株式会社. PDF
  2. K.Nakazawa, K.Murata, K.Ishihara, H.Iwakami, H.Horikoshi: The development of the high speed national project computer system. First USA-Japan Computer Conference proceedings, pp.173-181
  3. 森田宏, 石原孝一郎, 中澤喜三郎: HITAC 8800/8700のハードウェアについて. 電気通信学会電子計算機研究会資料. 1973-05. pp.1-13.