12
votes
Accepted
Does Deadlock imply Starvation
You should first state the deadlock freedom property and the starvation freedom property more precisely.
I use the definition in the Book: The Art of Multiprocessor Programming; Section 2.2.
Freedom ...
- 9,611
6
votes
Accepted
How to satisfy bounded waiting in case of deadlock?
You are correct.
Consider the simple synchronization algorithm which denies entry to all processes.
In this case we have both deadlock and bounded waiting, since any process $p$ is not bypassed by ...
- 13.5k
5
votes
Accepted
How does lack of deadlock relate to computability in process calculi?
I think you are asking about expressivity of concurrent programming languages. This is a deep and not well-understood field. For example you say that "the $\pi$-calculus [...] has the power to ...
- 8,358
4
votes
Accepted
Bounded waiting and starvation free in critical section problem
No, starvation-free doesn't imply bounded waiting.
For instance, consider a procedure that never even attempts to acquire any lock; but the amount of time it takes is variable and can be arbitrarily ...
D.W.♦
- 164k
4
votes
Accepted
Why deadlock in cigarette smokers problem
Agent A consumes agentSem, and produces tobacco and paper.
That might make Smoker I smoke but he is late: Smoker II already took the paper and Smoker III took tobacco.
Now, all the smokers are stuck,...
- 14.6k
3
votes
Accepted
In Operating Systems, I can't understand why deadlock happens, why does a process not let go of a resource when it is done using it?
To answer part of your question: Processes are not smart. Processes just execute the code of their program, so if the program of P1 has not been written to release R1 when it's done with it, it won't ...
- 29.6k
3
votes
Accepted
Bankers Algorithm-Is the system in safe state?
you can say there is no deadlock if there is a safe sequence for the completion, after $P1$ request is granted there must be a safe sequence where by which every process is completed.
...
3
votes
Accepted
Is this solution to the dining philosopher's problem entirely valid?
The description of an altruistic philosopher given in this answer, that you quoted in your question, is slightly imprecise. What it really is going on is that:
A possible approach for avoiding ...
- 146
3
votes
Accepted
Is Bounded Waiting satisfied for this 2 process Solution?
In the following, I treat the first two statements acquire(lock1) acquire(lock2) as "trying", the middle two statements ...
- 9,611
3
votes
Is bounded waiting satisfied in the 2 Process Solution?
A little remark first: The bounded waiting (BW) property is defined with respect to algorithms, which is in turn defined as a set of concrete executions. Thus, we cannot conclude whether an algorithm ...
- 9,611
3
votes
Accepted
A Dead-lock in an Operating System is
Your attempt "If a process is unable to change its state indefinitely because the resources requested by it are being used by another waiting process, then the system is said to be in a deadlock." is ...
- 31.5k
3
votes
difference between deadlock avoidance and detection
Simply to put
Deadlock avoidance: you employ some methods to avoid the deadlock ,but prevention is more restrictive than avoidance.
Deadlock detection: Here only the detection only takes place ...
3
votes
A real life system that faces and solves the dining philosophers problem
The dining philosopher's problem is a worst case scenario used to illustrate issues in algorithms. It's a test case. You probably won't find a static one-to-one mapping between it and a real world ...
- 13.8k
3
votes
Accepted
Deadlocks: Why if 2 threads are waiting for a lock from each other results in a deadlock?
The situation you are describing is not a deadlock.
A deadlock would be more like this:
Both Thread A and Thread B require both Lock 1 and Lock 2.
Thread A first acquires Lock 1, then Lock 2.
Thread ...
- 6,270
3
votes
Why does a lock ordering prevent deadlocks?
The four necessity conditions for deadlock are:
Mutual exclusion
Hold and Wait
No preemption
Circular Wait
Let there be two processes/threads - P1 and P2 and two resources - R1 and R2. Now assume ...
- 2,780
2
votes
When will deadlock occur in this producer-consumer code
It will be caused as follows:
Both processes blocked at the end, hence deadlocked.
- 1,763
2
votes
Accepted
How are semaphores and test-and-set instructions connected?
Semaphores are an abstract mechanism to control access to a shared resource. Other such mechanisms exist, for example locks and monitors. These are the counterparts of abstract data structures – they ...
- 278k
2
votes
Why does a lock ordering prevent deadlocks?
How you get a deadlock: Thread 1 waits for lock A and grabs it. Thread 2 waits for lock B and grabs it. Then thread 1 waits for lock B which is already locked and thread 2 waits for lock A which is ...
- 31.5k
1
vote
Exit a deadlock cycle
You don’t exit a deadlock cycle. Once you are in a deadlock situation, you lost. You do your best to avoid deadlocks.
With server software, you may be able to have a process that watches other ...
- 31.5k
1
vote
Does Dekkers solutions to critical section problem ensure progress?
The overall structure of the processes is modelled to be like:
...
- 14.1k
1
vote
Deadlocks in operating System
For a system to be in deadlock it must not be able to proceed. A process may be not started, complete, waiting for a resource, processing a resource, or be deadlocked.
It's normal for a process to ...
- 11
1
vote
How can I solve this deadlock related problem mathematically?
As per the question, all the even processes request only even resources(i.e. Ri & Ri+2)
Where as odd processes request:
either,
odd resources(i.e. Rn-1 & Rn-1-2) when 'n' is even.
or,
even ...
1
vote
Accepted
Designing solution to critical section problem with two semaphores vs single semaphore
If only one semaphore is used to control the access to the critical section, it is not possible for deadlock to happen. That is why two semaphores are used in the problem statement since the problem ...
- 39.1k
1
vote
Accepted
Can 2-philosophers problem be analogous to dining philosophers problem?
Short answer: yes, though it could be considered a "degenerate case" (that is, a case that ends up being somewhat different from most others).
Long answer: the Dining Philosophers problem is really ...
- 7,176
1
vote
Deadlock vs "Progress" requirement of the solution to the critical section problem
and this selection cannot be postponed indefinitely
In case of deadlock, deciding which process will enter next will be postponed indefinitely. So progress won't happen.
- 117
1
vote
Accepted
Can a safe state in Banker's Algorithm cause deadlock eventually?
No deadlock as long as you keep running the Banker's algorithm.
By definition, a state is considered safe if it is possible for all processes to finish executing, which means there is no deadlock.
...
- 39.1k
1
vote
Accepted
deadlock caused by a cyle of locks ? unprobable event causing it or just a false intuition
If a thread takes the Couple 5, the thread taking the couple 4 will lock D and wait, etc... to Couple 2.
Couple 1 tries to start and is waiting on A, couple 4 tries to start but is also waiting on A....
- 4,646
1
vote
Does starvation freedom imply progress?
It depends on how exactly you define "starvation freedom" and "liveness."
I believe the book is talking about starvation freedom from the perspective of the OS scheduler, which usually does not know ...
- 119
1
vote
Deadlock and safe state
That is not possible, when a deadlock occurs, the system is in an UNSAFE state. A safe state wouldn't have any purpose if a deadlock could occur.
- 353
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