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What is difference between counting and binary semaphore in os?
Wiki User
∙ 11y ago
Binary semaphore is a semaphore with the integer value ranges over 0 and 1 whereas the counting semaphore's integer value ranges over unrestricted domain. Binary semaphores are easier to implement comparing with the counting semaphore.
Binary semaphore allows only one thread to access the resource at a time. But counting semaphore allows N accesses at a time.
The 2 operations that are defined for binary semaphores are take and release.
The 2 operations that are defined for counting semaphores are wait and signal
Wiki User
∙ 11y ago
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Explain binary semaphore and its uses?
A binary semaphore is a semaphore with an integer value that can range only between 0 and 1. A binary semaphore can be simpler to implement than a counting semaphore, depending on the underlying hardware architecture.To implement it in terms of binary semaphores we need the following data structures: binary-semaphore S1, S2; i n t C; Initially S1 = 1, S2 = 0, and the value of integer C is set to the initial value of the counting semaphore S.The wait operation on the counting semaphore S can be implemented as follows: wait (S1) ; c--; i f (C < 0) { signal(S1) ; wait (S2) ; } signal(S1) The signal operation on the counting semaphore S can be implemented as follows: w a i t (S1) ; C++ ; i f (C <= 0) signal (S2) ; e l s e signal (S1) ;
Explain semaphore concept in multiprogramming?
A semaphore is a service very often offered by real-time operating systems to allow programmers to perform one of two major functions: synchronize 2 tasks or control sharing of resources between 2 or more tasks. There are different kinds of semaphores, but one of the most common is called a binary semaphore. In this kind of semaphore, only 1 task at a time may "have" the semaphore. The simplest way to think of the binary semaphore might be to consider the semaphore like a baton and there is only one baton. Say if you want to allow only 1 person to speak at a time (consider people to be tasks), then you make a rule that only the person holding the baton may speak. A person wanting to speak will go and pick up the baton. If nobody else has it, he may speak. If someone else has it, he must wait until the baton is put down by whoever has it. This is the "sharing resources" way a semaphore is used. The task synchronization usage, similarly can be thought of using this baton. Just as in a relay race where one person cannot start until another passes the baton, a binary semaphore can be used to synchronize two tasks by giving one task the semaphore, having the second one wait for the semaphore, and then having the first give it to the second. The two tasks will be synchronized at the point the semaphore is passed from the first to the second just as a baton is passed from one runner to the next in a relay race. You can have semaphores other than binary semaphores, which are called counting semaphores. Counting semaphores are just binary semaphores generalized to more than the 2 values of 0 and 1, to some value n.
What are the types of semaphores?
Three types of semaphores: 1.General/Counting semaphores: (can take any non-negative value) These are used when you might have multiple devices (like 3 printers or multiple memory buffers). 2.Binary semaphores: (can either be 0 or 1) These are used to gain exclusive access to a single resource (like the serial port, a non-reentrant library routine, or a hard disk drive). A counting semaphore that has a maximum value of 1 is equivalent to a binary semaphore (because the semaphore's value can only be 0 or 1). 3.Mutex semaphores: These are optimized for use in controlling mutually exclusive access to a resource. There are several implementations of this type of semaphore.
What is the difference between MUTEX and Semaphore?
From wikipedia:"A mutex is a binary semaphore, usually including extra features like ownership or priority inversion protection. The differences between mutexes and semaphores are operating system dependent. Mutexes are meant to be used for mutual exclusion only and binary semaphores are meant to be used for event notification and mutual exclusion."They also have a good example as to the use of a semaphore:"A thread named A needs information from two databases before it can proceed. Access to these databases is controlled by two separate threads B, C. These two threads have a message-processing loop; anybody needing to use one of the databases posts a message into the corresponding thread's message queue. Thread A initializes a semaphore S with init(S,-1). A then posts a data request, including a pointer to the semaphore S, to both B and C. Then A calls P(S), which blocks. The other two threads meanwhile take their time obtaining the information; when each thread finishes obtaining the information, it calls V(S) on the passed semaphore. Only after both threads have completed will the semaphore's value be positive and A be able to continue. A semaphore used in this way is called a 'counting semaphore.'"Basically think of a semaphore as a lock that allows multiple threads to wait in line for the resource to be free. Usually they will block and the semaphore will wake them up when it is their turn.
What is difference between binary tree?
fish!
Is there a difference between binary fusion and cell division?
Yes
What is the difference between binary heap and binomial heap?
The difference between Binomial heap and binary heap is Binary heap is a single heap with max heap or min heap property and Binomial heap is a collection of binary heap structures(also called forest of trees).
Difference between a well and flat slide?
it is called a binary fission
What is the difference between binary and general semaphores?
the differents is the bathroom time
What is the difference between unary and binary?
In programming a unary and binary operator defines how many components make up an expression.
In binary number counting what does ten stand for?
The binary number 10 represents 2. The decimal number 10 in binary would be 1010.
What is the difference between binary codes and bcd codes?
In BCD each digit of a decimal number is coded as a separate 4 bit binary number between 0 and 9.For example:Decimal 12 in BCD is shown as 0001 0010 (Binary 1 and Binary 2), in Binary it is 1100.
