Operating System

Oparaing systems can divide main memory into portions called so that one process cannot ovemuite anodher s memoly, either midvertently or malcousily sections partitions modules regons Strategies determine which pieces of data to remove from main memory to free space for a new process. Fetch Placement Replacement both a and c strategies attempt to load a piece of program or data into memory before it is referenced Demand fetch Anticipatory fetch First-fit placement Next-fit placement In general, the overhead incurred by allocation is cutweighed by the advantapes of benig able to storo more processes in main menory af the some fine contiguous noncontiguous fragment segment A(n) can be used in single-user contiguous memory allocation systems to prevent prograns from damoging the operating systems memory lock protection bit boundary register semaphore