Starts abridging accounts using an old computer (6)
I believe the answer is:
abacus
'computer' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for abacus that I've seen before include "Counting-bead device" , "An ancient counting frame with beads" , "summer once?" , "As a cub (anag)" , "Beaded counting frame" .)