Yes, it really was embedded. It fit in 9U (15.75 inches) and was rugged enough to fly in a military aircraft. The OS would let users turn off interrupts in order to squeeze out every bit of performance.
We could also run the OS on the SHARC DSP, which is a word-addressed Harvard-architecture chip without an MMU. Running on that would allow 3x the CPU density. One system got up over 1000 cores.
IO would typically come in via DMA, over a 32-bit link running at 40 MHz. There could be many of these.
The end result was generally something like a radar. The end-user sees a radar, buys a radar, and uses a radar. They don't see a computer. The computer is just a component embedded in the radar.
Even back then, FPGAs and custom ASICs would be part of the compute fabric. I left that out. For example, there was an FFT accelerator chip. These days the companies add in a mix of FPGAs and GPUs, but the CPUs are still there. It's all the same stuff today, but faster.
To the end user, it was never a computer. It was a radar, a video processor, an MRI scanner, a sonar, an ultrasound, a chip wafer inspection device, a laser with real-time mirror warping, or some other tool.
They probably should be considered the norm if it's embedded without unusually-high performance requirements.