Solution

Given :

Disc queue: 45, 81, 185, 33, 175, 99, 150, 77.
Head starts at 58.
Find the 2nd request processed by SCAN (LEFT).

SCAN (LEFT) rule (brief):
Start from the current head and move strictly toward lower-numbered cylinders first, serving requests as encountered. After finishing that side, the head goes to the left end (0) and then reverses to serve the remaining requests to the right (not needed here for “2nd request”).

Steps

• Requests < 58 (to the left): {45, 33} → in the actual order met while moving left: 45, then 33.

• Therefore:
  1st served: 45
  2nd served: 33 ✅

Answer: 33