ITPEC IP April 2019 Question 17
Topic: Software
What is the minimum amount (in Mbytes) of virtual memory that is required under the conditions below?
[Conditions]1.Memory required for the OS: 200 Mbytes2.Memory required for applications: An amount of 50 Mbytes is required for each application, and a total is calculated by multiplying it by the number of applications that run concurrently. Eight (8) applications run concurrently.3.Memory required for controlling main memory or other related functions: In addition to 512 Mbytes of main memory, a minimum amount of 20 Mbytes is required.4.Required virtual memory: The required amount is the sum of the above 1 through 3.
Explanation
1,132 Mbytes — add the OS, the eight applications and the memory-control requirement, as condition 4 says.
- •OS (condition 1): 200 Mbytes
- •applications (condition 2): 50 × 8 = 400 Mbytes
- •memory control (condition 3): 512 Mbytes of main memory plus 20 Mbytes, 512 + 20 = 532 Mbytes
- •total (condition 4): 200 + 400 + 532 = 1,132 Mbytes
Answer (d)
Why not others:
- •(a) 762 — 200 + 50 + 512: counts one application instead of eight, and leaves out the 20 Mbytes
- •(b) 782 — 200 + 50 + 512 + 20: counts only one application's 50 Mbytes, not 50 × 8
- •(c) 1,112 — 200 + 400 + 512: leaves out the extra 20 Mbytes of condition 3
Key rule: Virtual memory lets programs use more memory than main memory holds by borrowing auxiliary storage; to size it, add every stated requirement, multiplying per-program amounts by the number running concurrently.
Software · AI-written, may contain errors
This question comes from an official ITPEC past paper. ITPEC Practice is an independent study tool and is not affiliated with ITPEC. See the official IP past-paper collection or Report an issue.