Day 01Part 08- Operating system lecture for gate for computer science – Attributes of Processes.<\/p>\n
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A process<\/strong> in an Operating System (OS) is an instance of a program in execution<\/strong>. Every process has certain attributes that help the OS manage and schedule it efficiently.<\/p>\n A process<\/strong> is a program in execution, consisting of: Each process has a unique set of attributes<\/strong> stored in the Process Control Block (PCB)<\/strong>.<\/p>\n A process can be in one of the following states: Example:<\/strong> If a process is waiting for input from the keyboard, it moves to the Waiting<\/strong> state.<\/p>\n Example:<\/strong> If a process tries to access memory outside its boundary, the OS generates a segmentation fault<\/strong>.<\/p>\n Example:<\/strong> The OS uses this data for scheduling<\/strong> and billing<\/strong> in time-sharing systems.<\/p>\n Example:<\/strong> If a process is reading a file, it stays in the Waiting<\/strong> state until I\/O is complete.<\/p>\n \u00a0Process Control Block (PCB)<\/strong><\/p>\n All process attributes<\/strong> are stored in a data structure called the Process Control Block (PCB)<\/strong>.<\/p>\n\u00a0What is a Process?<\/strong><\/h3>\n
Program Code (Text Section)<\/strong> \u2013 The instructions to be executed.
Program Counter (PC)<\/strong> \u2013 Stores the next instruction to execute.
Stack<\/strong> \u2013 Contains function calls, return addresses, and local variables.
Heap<\/strong> \u2013 Dynamic memory allocation (e.g., malloc in C).
Data Section<\/strong> \u2013 Global variables and static data.<\/p>\n\u00a0Attributes of a Process<\/strong><\/h3>\n
1. Process ID (PID)<\/strong><\/h3>\n
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2. Process State<\/strong><\/h3>\n
New<\/strong> \u2013 Process is being created.
Ready<\/strong> \u2013 Waiting for CPU time.
Running<\/strong> \u2013 Currently executing on the CPU.
Waiting (Blocked)<\/strong> \u2013 Waiting for I\/O or other resources.
Terminated<\/strong> \u2013 Process has finished execution.<\/p>\n3. Program Counter (PC)<\/strong><\/h3>\n
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4. CPU Registers<\/strong><\/h3>\n
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5. Memory Management Information<\/strong><\/h3>\n
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Base and Limit Registers<\/strong> \u2013 Define memory boundaries.
Page Tables<\/strong> \u2013 Used in virtual memory systems.
Segment Tables<\/strong> \u2013 Used in segmentation memory management.<\/li>\n<\/ul>\n6. Accounting Information<\/strong><\/h3>\n
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\u00a0CPU usage\u00a0
\u00a0Execution time\u00a0
Process priority\u00a0
\u00a0Number of I\/O operations performed<\/li>\n<\/ul>\n7. I\/O Status Information<\/strong><\/h3>\n
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\u00a0List of open files\u00a0
\u00a0I\/O device usage<\/li>\n