HP 1000 M-Series, 2108A
The 2108A is part of the HP 2100 series of 16-bit minicomputers that were produced from 1975 through 1979. The 2108 featured memory management and semiconductor memory that was expandable to 640 kBytes. The used small red LEDs instead of the more common incandescent bulbs used in competing products. The 21MX ran the HP RTE (Real Time) Operating System (OS).
This system is missing most of the boards so it will take a bit of work to get it running. Since it has a blue line on front panel it is an M-series, and since it is 8-3/4 inches tall it is a 2108.
This system came with 2102A memory, 12944A battery backup, and 1289/A option.