How to use the Banker's Algorithm Calculator
- 1. Enter the matricesOne row per process for Allocation and Max, plus the Available vector.
- 2. Check safetyOptionally test a new request like P1: 1 0 2.
- 3. Read the stepsSee which process runs at each step and how Work grows.
How the algorithm decides
The Banker's algorithm, by Dijkstra, avoids deadlock by granting resources only if the system stays in a safe state: one where there is some order in which every process can still finish.
- Need = Max − Allocation: what each process may still ask for.
- Work starts as Available. Find a process whose Need fits in Work; pretend it runs and finishes, so its Allocation is added back to Work. Repeat.
- If every process can finish this way, the state is safe and the order is a safe sequence. If some can never finish, the state is unsafe.
For a resource request, the request must not exceed the process's Need or what is Available. If those pass, the tool pretends to grant it and runs the safety check; the request is granted only if the result is still safe.
Worked example
The sample is the classic textbook case: 5 processes and 3 resource types (A, B, C) with Available = (3 3 2). The Need matrix comes out as P0 (7 4 3), P1 (1 2 2), P2 (6 0 0), P3 (0 1 1) and P4 (4 3 1).
Scanning in order: P0 needs too much, P1's (1 2 2) fits, so P1 runs and Work becomes (5 3 2). Then P3 fits, Work (7 4 3); then P4, Work (7 4 5); then P0, Work (7 5 5); and finally P2, Work (10 5 7). The system is safe with sequence P1 → P3 → P4 → P0 → P2.
Try the request P1: 1 0 2: it fits P1's need and what's available, and the state afterwards is still safe, so it can be granted. Other safe sequences can exist; this tool always scans P0, P1, P2 … in order, the way most textbooks do.
Frequently asked questions
Why can a request be refused even when resources are free?
Because granting it might leave the system unsafe, where a future set of requests could deadlock. The algorithm plays it safe.
Is an unsafe state a deadlock?
Not yet. Unsafe means a deadlock is possible, not certain.
How many processes and resources can I enter?
As many as you like; just keep every row the same length as Available.
Is the banker's algorithm calculator free to use?
Yes, the banker's algorithm calculator is free and costs nothing. Your first safety check shows a short form for your name and WhatsApp number one time; once that's done, this tool and every other Uncodemy tool open with no form.