These boards are from Hitachi HITAC 8800 computer that started its operation at The University of Tokyo Computer Center on January 1973 . 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 . However, the 8800 and 8700 supports virtual memory and shared-memory multiprocessing with sort of page-granularity directory-based coherent cache .
Following modules are referred to as
plugins in .
Two PCBs are connected using silver coaxial cables.
Patterns on PCBs are laid out in a way that is similar to IBM 5110's.
All these board-sets are unidentified.
Second unidentified boardset.
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.
Identity of these modules are not documented in literature.
Identity of following modules are also undocumented.
Could be from other kind of Hitachi computer.