Paravant RHC-88 Computer. Is very rare and difficult to find, especially in this condition (battery tray is unbelievably clean) and I would consider this computer to be "Museum" quality.
Tested and working! Loaded with MS DOS 3.2 and has 3 User ROM eprom slots (currently one is installed) and 2 Bayonet connectors on the top for external serial devices and 120v ac-dc power supply adapter (power supply not included).
This unit was designed and built for the US military and began research in late 1970s/ early 1980s. Very great condition inside and out.
Reach out with any questions, documentation, or for additional pictures or info.
"Can it run DOOM?" - Probably.
$400 OBO
The link below is a PDF with some technical information and documentation on the Development and History:
https://apps.dtic.mil/sti/tr/pdf/ADA229421.pdf