Also y second psrt is inserted traduonal symbols and colored ticks and stamps?is it necessary for audit trail answer.Reference audit pm ipcc page 4.6-4.7 question 5.
First watch below video which explains this question in brief and then read this specific explanation
They want to say that, in earlier manual system, audit trail was available easily and some early generation computers also it was available and it was very easy to trace items from start till end and auditor could mark items with his ticks or other symbols and it was very convenient for him.
[Starts from 00:14:43-minute RTP Video 2]
Link :- https://www.youtube.com/watch?v=2LZ7YlTTp_Y