Category Archives: Operating System

Logical Structure of a directory – File Management

Logical Structure of a directory Logical Structure of a directory: The directories can be structured in the following ways: Single level directory Two level directory Tree structure directory Acyclic graph directory General graph directory 1. Single Level directory It is the simplest form of Logical Structure of a directory having only one level of directories.… Read More »

File Management – Access Methods

Access Methods in File Management Files are used to store data. The information present in the file can be accessed by various methods. Thus, the way of retrieving data from a file is known as access method. Different systems use different access methods. The various access methods used are: Sequential access Direct access Indexed access… Read More »

Thrashing – Virtual Memory

Thrashing Thrashing is a situation in which a system spends more time in processing page faults than executing instructions of processes. Thrashing degrades the performance of a system. There may be a situation when the memory is full with pages that are accessed frequently. A page fault will occur if the required page is not… Read More »

Allocation Algorithm – Virtual Memory

Allocation Algorithm There are two different methods of  allocating frames to different process. These are: Equal allocation Proportional allocation 1. Equal allocation This allocation method divides the available page frames equally among all the processes. i.e. if we have m frames and n processes then we can divide m frames among the n processes. For… Read More »

Locality – Virtual Memory

Locality Central to most memory management techniques is the concept of locality – that processes tend to reference storage in nonuniform, highly localized patterns. Locality exhibit itself in two forms:  Temporal locality Spatial locality 1. Temporal Locality Temporal locality means that storage locations referenced recently are likely to be referenced in the near future. For… Read More »

Segmentation-Operating System

Segmentation is  a memory management technique in which process is dividing into the segments and the segments are of variable size. The details about each segment are stored in a table called a segment table. Segment table is stores mainly two information of the segments. Base: It is the base address of the segment Limit:… Read More »