It's probably SMPS but that's not crystal clear. For 230VAC to 12.1VDC@8A, I would expect to see bigger magnetics in a linear supply.
If it is SMPS and you're seeking to replace it, I would just remove everything but the frame and connector and bolt on a new off-the-shelf 100W unit. The new one would be quite a bit smaller I think so it should fit onto the frame nicely.
Should be easy enough to tell for sure by tracing the power input. If it is power input->fuse->transformer->rectifier/16V caps then it is linear, if it is power input->fuse->rectifier/350V caps->transistors->transformer then it is a switcher.
In the beginning of smps, there was often a xfmr that provided raw rectified voltage to the switcher, because high voltage transistors were not available.
The idea was to increase efficiency and minimize heat, but not weight.