The computer was inspired by or was successor to TPA-11/40.
Parts of this topic may be machine translated.
Improved TPA-11/40. Improvements included 22-bit maps, I/D splitting, cache, etc., so it performed enough like an 11/70 to "fool" DEC operating systems. It ran much slower than the real 11/70 (actually the 11/48 was slower than the TPA-11/40).