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Operating System Support. Akhilesh Shresthacharya Anish Joshi Anish Manandhar Ashmita Shakya Bijaya Laxmi Das. Agenda. Operating System Overview Objectives of Operating system Layers of Operating system Types of Operating System Scheduling Memory Management.
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Operating System Support AkhileshShresthacharya Anish Joshi AnishManandhar AshmitaShakya BijayaLaxmi Das
Agenda • Operating System Overview • Objectives of Operating system • Layers of Operating system • Types of Operating System • Scheduling • Memory Management
Operating System Overview • It the software on a computer that manages resources. • Under this software all the other software are being run. • For e.g. Windows7, Linux, Ubuntu etc.
Objectives of Operating System • Convenience: Makes computer more convenient to use. • Efficiency: Allows computer system resources to be used in efficiency. • Ability to evolve: permit effective development testing and introduction of new system function without interfering with services.
Types of Operating System Interactive • Late 1940s and 1950s • Program interacts directly with hardware • Two main problem: • Scheduling • Setup Time
Types of Operating System Batch system • Resident monitor program • Users submit jobs to operator • Operator batches jobs • Monitor controls sequence of events to process batch • When one job is finished, control returns to monitor which reads next jobs • Monitor handles scheduling of jobs
Types of Operating System Single programming (uni- programming) • Only one job in CPU at a time • Next job starts when previous job cycle complete.
Types of Operating System • Multi programming
Scheduling • Scheduling refers to the way processes are assigned to run on the available CPUs. • Types of scheduling: • 1. Long-term scheduler • 2. Mid-term scheduler • 3. Short-term scheduler
Memory Management • Memory management is the act of managing computer memory • This involves providing ways to allocate portions of memory to programs at their request • Types are given on next slide:
Swapping • This swapping is method in which the management of the memory is done by the swapping of memory and Disk storage • It is a process to make the operating system more fast
Partitioning • The simplest scheme for partitioning available memory is to use fixed-size partitions. • Types: • Fixed-size partition • Variable-size partition
Paging • However that memory is partitioned into equal fixed sized chunks of some size. • Then the chunks of a program known as pages could be assigned to available chunks of memory.
Virtual Memory • Virtual memory is a memory management technique developed for multitasking. • If there is only one hardware memory device and this "virtual" device(harddisk) acts like a RAM module.