<- People Behind Informatics


All 0-9 A B C D E F G H I J K L M N O P Q R S T U V W XY Z




 
Bankers Algorithm
A scheduling algorithm that can avoid deadlocks is due to Dijkstra (1965) and is known as the banker’s algorithm. The name was chosen because this algorithm could be used in a banking system to ensure that the bank never allocates its available cash such that it can no longer satisfy the needs of all its customers. When a new process enters the system, it must declare the maximum number of instances of each resource type that it may need. This number may not exceed the total number of resources in the system. When a user requests a set of resources, the system must determine whether the allocation of these resources will leave the system in a safe state. If it will, the resources are allocated; otherwise, the process must wait until some other process releases enough resources. Bankers algorithm (safe/unsafe states) A state is said to be a safe state if there exists a sequence of other states that leads to all the customers getting loans up to their credit limits (all the processes getting all their resources and terminating). An unsafe state does not have to lead to deadlock, since a customer might not need the entire credit line available, but the banker cannot count on this behaviour. [Sources: Tanenbaum, 1987, Andrew S., Tanenbaum, Operating Systems – Design and Implementation Silberschatz, Galvin, 1994 Abraham Silberschatz, Peter B. Galvin, Operating System Concepts]
 

 

<- People Behind Informatics


Home  |  Top  |  Search  |  Gallery  | Glossary  | Sitemap  |  Making Of  |  Help