CSC 553 - Operating Systems
Dr. R. M. Siegfried
Assignment #6 - p. 304-305/6.1, 6.5
Due Wednesday, October 11, 2023
6.1
Show that the four conditions of deadlock apply to figure 6.1a (the third slide
of Lecture 6).
6.5
Given the following state for the Banker's Algorithm:
- 6 processes P0 through P5
- 4 resource types:
- A (15 instances)
- B (6 instances)
- C (9 instances)
- D (10 instances)
- Snapshot at time T0
Available
| A | B | C | D |
| 6 | 3 | 5 | 4 |
Current Allocation
| Process | A | B | C | D |
PO | 2 | 0 | 2 | 1 |
P1 | 0 | 1 | 1 | 1 |
P2 | 4 | 1 | 0 | 2 |
P3 | 1 | 0 | 0 | 1 |
P4 | 1 | 1 | 0 | 0 |
P5 | 1 | 0 | 1 | 1 |
Maximum Demand
| Process | A | B | C | D |
PO | 9 | 5 | 5 | 5 |
P1 | 2 | 2 | 3 | 3 |
P2 | 7 | 5 | 4 | 4 |
P3 | 3 | 3 | 3 | 2 |
P4 | 5 | 2 | 2 | 1 |
P5 | 4 | 4 | 4 | 4 |
Need is Maximum Demand - Current Allocation
- Verify that the Available array has been correctly calculated.
- Calculcate the Need matrix
- Show that the current state is safe, i.e, show a safe sequence of processes.
In addition, to the sequence show how the Available (working array) changes as
each process terminates.
- Given the request (3, 2, 3, 3) from Process P5. Should this request be
granted? Why or why not?
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