CS/OS
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SynchronizationCS/OS 2024. 4. 21. 23:03
Race Condition Synchronization Solve problem causing by accessing to shared resources. Without synchronization, it lead to incorrect results, called race condition. A way to coordinate threads (or processes) that use shared resources or their execution for correctness. Goal of synchronization is ensuring correct operation of cooperating threads. Race Condition The result by threads accessing sha..
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ThreadsCS/OS 2024. 4. 17. 15:44
Terminologies Concurrency (동시성 / 병행성) : the ability of two or more threads to execute in interleaving (overlapping) time periods and proceed at same time. Parallelism (병렬성) : the ability of two or more threads to execute in overlapping at same time. Porcess (Task) : the unit of resource ownership A compound entity (a set of threads + a collection of resource) Thread (Lightweight process) : The u..
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Process Scheduling 2CS/OS 2024. 3. 20. 14:36
Terminologies Burst (time) CPU burst : time it takes for CPU to execute an operation. I/O burst : time it takes for the CPU to wait for I/O. CPU-I/O burst cycle Each process execution consists of a cycle of CPU execution and I/O wait. Alternating CPU and I/O bursts. Processes can be described as I/O-bound process : I/O-intensive (CPU burst < I/O burst) CPU-bound process : CPU-intensive (CPU burs..
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Process Scheduling 1CS/OS 2024. 3. 13. 17:44
Types of Process Scheduling Long-term scheduling (job scheduler) : determines which programs are admitted to the system for processing Medium-term scheduling (swapper) : the decision to add to the number of processes that are partially or fully in main memory Short-term scheduling (CPU scheduler) : the decision as to which available process will be executed by the processor I/O scheduling Schedu..
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Process Description and ControlCS/OS 2024. 3. 6. 19:54
Terminologies : Program and Process Program vs Process Program : passive entity stored stored on disk (binary sequence) Process : active entity (execution sequence) Program becomes process when executable file loaded into memory Two essential elements of a process Program code A set of data associated with that code Process A program in execution The entity that can be assigned to and executed o..
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User Program and System CallCS/OS 2024. 3. 6. 17:12
Terminologies : Kernel and Utility Kernel : Operating System의 핵심적인 기능을 수행하는 코드 (Software) Memory resident part of OS Majority written in C / Rest in assembler language (HW dependent, for speed) Consists of a set of functions Provide fundamental mechanisms (process management, synchronization, CPU scheduling, memory management, device management, interrupt handling) Provide services via a system ..
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Computer System OverviewCS/OS 2024. 2. 26. 16:05
Basic Element Processor Arithmetic / Logic Unit (ALU) : performs mathematical calculations and makes logical comparisons Central Process Unit (CPU) : a hardware component that performs an instruction set utilizing the ALU, control unit, and registers Graphical Process Unit (GPU) : provide efficient computation on arrays of data using Single-Instruction Multiple Data (SIMD) techniques SoC : compo..