Directory creation and deletion support of primitives

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– Directory creation and deletion. – Support of primitives for manipulating files and directories. -File backup on stable (nonvolatile) storage media.
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SUSHMA RAWAL 23 I/O System Management • The I/O system consists of: – A buffer-caching system – A general device-driver interface – Drivers for specific hardware devices
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SUSHMA RAWAL 24 Secondary-Storage Management • Since main memory ( primary storage ) is volatile and too small to accommodate all data and programs permanently, the computer system must provide secondary storage to back up main memory. • Most modern computer systems use disks as the principle storage medium, for both programs and data. • The operating system is responsible for the following activities in connection with disk management: – Free space management – Storage allocation
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SUSHMA RAWAL 25 Networking (Distributed Systems) • A distributed system is a collection processors that do not share memory or a clock. Each processor has its own local memory. • The processors in the system are connected through a communication network. • Communication takes place using a protocol. • A distributed system provides user access to various system resources. • Access to a shared resource allows: – Computation speed-up – Increased functionality – Increased data availability
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SUSHMA RAWAL 26 Protection System Protection refers to a mechanism for controlling access by programs, processes, or users to resources. • The protection mechanism must: – distinguish between authorized and unauthorized usage. – specify the controls to be imposed. – provide a means of enforcement.
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SUSHMA RAWAL 27 Command-Interpreter System • Many commands are given to the operating system by control statements which deal with: – process creation and management – I/O handling – secondary-storage management – main-memory management – file-system access – protection – networking
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SUSHMA RAWAL 28 Command-Interpreter System (Cont.) • The program that reads and interprets control statements is called variously: -command-line interpreter – shell (in UNIX) • Its function is to get and execute the next command statement.
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29 Operating System Services • Program execution – system capability to load a program into memory and to run it. • I/O operations – since user programs cannot execute I/O operations directly, the operating system must provide some means to perform I/O. • File-system manipulation – program capability to read, write, create, and delete files. • Communications – exchange of information between processes executing either on the same computer or on different systems tied together by a network. Implemented via shared memory or message passing . • Error detection – ensure correct computing by detecting
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Directory creation and deletion Support of primitives for...

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