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Related Flashcards
Cards In This Set
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Primary Storage
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Main memory, directly accessible by the CPUProgram must be in main memory to runMain memory is volatile (loses contents on power loss/reboot)RAM
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Secondary storage
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Holds large quantities of dataHard drive
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Device driver
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For each device controllerunderstands the controller and provides a uniform interface tot he device to the OS
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Starting IO operation
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Device driver loads the appropriate register within device controllerDevice controller examines the contents of these registers
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When transfer is complete
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Device controller informs the device driver with an interruptDevice driver returns control to OS
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Direct Memory Access
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Transfer blocks of data to/from memoryController raises interrupt when transfer is complete per block
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Single processor system
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PDA's to mainframesMostly used as special-purpose processors
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Advantages of multi-processor system
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Increase throughput (more work done)Economy of scale (cost less then multi single processor systems)Increased reliability (distribution of processes)
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Types of multi-processor system
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Asymmetric multi-processing- each processor assigned a specific taskSymmetric multi-processing- all processors perform tasks within the OS (not common)
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Operating System Services
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Provides environment for the execution of programs
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I/O operations
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User program cannot directly access IO hardware, OS does the low level part for them
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Communication
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Help between inter process on same computerBetween computers over a networkvie shared memory or through message passing
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Error Detection
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OS needs to be aware of all possible errorsOS handles them appropriately to ensure correct and consistent computing
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Resource allocation and management
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When multiple users/jobs are running concurrently resources will be allocated to each of them
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Accounting
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Keep track of which user is using what kind of computer resources
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