I am just listening to Robin sharma audio program, and focusing on to-do list, I got an idea on IMSDB. I decided to give some tough questions here.
You can buy popular IMSDB/IMSDC books on-line here.
Q1)In DL/I Database elements are organized in hierarchical structure. There are max 255 segments and 15 levels are possible in a database
Q2)Top-Down-Left-Right is the approach data can be accessed-This is called sequential processing
Q3)For Random processing, key(sequence) field is required. Through concatenated key (from root segment to the segment that you want), randomly record can be accessed.
Q4)DL/I acts as middle layer between Application program and database
Q5)DBD tells complete structure of the database. PSB is program’s view of the database. That means, for a DBD, multiple PSBs are possible.
Q6)PROCOPT=G,R,I etc (check my part-1 for more on this)states access permissions on the database. Also, we can call as locks.
Q7)ACB-also called access control block.It merges PSBs and DBDs into IMS-internal format when application program starts to execution.