What is Operating system?
Software and/or firmware programs that control and manage computer resources.
Computer Resources:- Hardware :CPU, INPUT DEVICES, MEMORY, OUTPUT DEVICES,.. Data : ORGNIZATION INFORMATION, KNOWLEDGE BASES, DATABASES,…..
Major Operating system Functions:-
• Provide user interface
• Sharing hardware between users
• Sharing data between users
• Preventing users interference.
• Scheduling resources.
• Facilitating input/output
• Recovery from errors.
• Accounting for usage of resources.
• Handling networking communication.
• Organizing data in secure way and rabid access.
Hardware Concepts
• Storage Interleaving. • Relocation registers. • Interrupts. • Polling • Buffering • Boundary Registers. • Timers and Clock • Input / Output Channels • Cycle Stealing/DMA • Base Registers • Pipelining. • Storage Hierarchy
Hardware Concepts
• API : Application Program Interface • Facility provided by the operating systems manufactures to allow the processes ask for service or get access to system devices (since the operating system control and manage computer resources) • Also called System calls
• Cache : a high speed memory that allows the processor to get access to data and instructions at very high speed. Level one L1 hosted by the processor chip. Level two L2 is hosted on the processor hosting board.
Software Concepts
• Input / Output Control system. • Spooling • Compilers • Interpreters. • Loaders
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