Operating System
OS Part-1
OS Part-2
- File Concepts and Access methods
- Free Space Management and Allocation methods
- Directory Systems and Protection
- File Organization, Sharing and Implementation issues
- Disk and Drum Scheduling
- I/O Devices Organisation & I/O Buffering
- I/O Hardware, Kernel I/O subsystem and Transforming I/O Requests to Hardware Operations
- Device Drivers and Path Management
- Device Driver Sub Modules and Procedure
- Device Scheduler and Handler
- Interrupt Service Routine (ISR)
- File System in Linux and Windows
OS Part-3
- Process and Process Control Block(PCB)
- Process Scheduling( Preemptive and Non Preemptive)
- Scheduling Algorithms
- Algorithm Evaluation
- Multiple Processor Scheduling
- Real Time Scheduling
- Operations on Processes
- Threads
- Inter-Process Communication
- Precedence Graphs
- Critical Section Problem
- Semaphores
- Classical Problems of Synchronization
- DeadLock
- Deadlock Prevention and Avoidance
- Deadlock Detection and Recovery
- Process Management in Linux
OS Part-4
- Memory Hierarchy in OS
- Concepts of Memory Management
- MFT and MVT
- Logical and Physical Address Space
- Swapping
- Contiguous and Non Contiguous Memory Allocation
- Paging
- Segmentation
- Paging Combined with Segmentation
- Structure and Implementation of Page Table
- Virtual Memory in OS
- Cache Memory Organization
- Demand Paging
- Page Replacement Algorithms
- Allocation of Frames and Thrashing
- Demand Segmentation
OS Part-5
- Distributed Operating System: Introduction and Types
- Distributed OS: Design Issues
- Distributed OS: File System
- Distributed OS: Remote File Access
- Remote Procedure Call(RPC)
- Remote Method Invocation(RMI)
- Distributed Shared Memory
- Parallel Processing and Concurrent Programming
- Security and Threats Protection in Distributed OS
- Security Design Principles and Authentication in Distributed OS
- Sensor Network and Parallel OS
Operating System Design & Implementation Kya Hota Hai?
Operating System (OS) ka design aur implementation ka matlab hai OS ka architecture banana, uske features develop karna, aur OS ko functional banana.
Design = OS ka structure aur architecture plan karna.
Implementation = Code likhna aur OS ke components ko integrate karna.
OS Design Goals
Jab hum ek OS design karte hain, toh kuch important goals hote hain:
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Efficiency – OS fast aur smoothly chale.
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Security & Protection – User aur data safe rahe.
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User-Friendly Interface – OS ka use karna easy ho.
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Portability – OS different hardware pe smoothly chale.
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Scalability – OS bade systems aur workloads ko handle kar sake.
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Reliability – OS crash hone ya error aane par recover ho sake.
OS Design Approaches
OS ko design karne ke alag-alag tareeke hote hain. Har ek ka apna advantage aur disadvantage hota hai.
1. Monolithic Architecture (Ek Bada Kernel)
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Poora OS ek single program ke roop me run hota hai.
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Saare components ek saath interconnected hote hain.
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Examples: Linux, UNIX, MS-DOS
Pros: Fast execution, simple design.
Cons: Difficult to modify aur debug karna mushkil hota hai.
Diagram: Monolithic OS Design
2. Layered Architecture
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OS multiple layers me divide hota hai, jisme har ek layer apna specific kaam karti hai.
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Example: Windows NT, THE OS
Pros: Easy debugging aur modification.
Cons: Multiple layers hone ki wajah se execution slow ho sakta hai.
Diagram: Layered OS Design
3. Microkernel Architecture (Chhota Kernel, Baaki Services User Mode me)
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OS ka core part (microkernel) sirf essential services ko handle karta hai, jaise process management aur memory management.
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Baaki services (file system, device drivers) user mode me run hoti hain.
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Examples: MacOS, QNX, Minix
Pros: Secure aur stable hota hai.
Cons: Slow ho sakta hai kyunki extra communication lagta hai.
Diagram: Microkernel OS Design
4. Hybrid Architecture (Monolithic + Microkernel ka Mix)
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Yeh dono architectures ka best combination hai.
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Core monolithic kernel hota hai, par extra features ko modules ke roop me add kiya jata hai.
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Example: Windows, Linux with Loadable Kernel Modules
Pros: Flexible aur fast.
Cons: Complexity badh jati hai.
OS Implementation
OS design hone ke baad usko implement kiya jata hai, jisme coding aur testing hoti hai.
1. Programming Language Selection
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C aur Assembly Language OS development ke liye sabse popular hain.
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Example: Linux Kernel C aur Assembly me likha gaya hai.
2. Bootstrapping (System Boot Process Implement Karna)
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OS ka bootloader hardware initialize karta hai aur kernel ko RAM me load karta hai.
3. Process Management Implement Karna
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OS ka kernel process create, schedule aur execute karta hai.
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Example: Round Robin Scheduling ka implementation.
4. Memory Management Implement Karna
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Paging aur Segmentation techniques ka use karke RAM ka allocation kiya jata hai.
5. File System Develop Karna
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OS NTFS (Windows), ext4 (Linux), HFS+ (MacOS) jese file systems ko implement karta hai.
6. Device Drivers Banane ka Kaam
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OS hardware jaise printer, keyboard, USB devices ke liye drivers develop karta hai.
7. Security & User Management
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OS me authentication, encryption aur access control add kiya jata hai.
Example: OS ka Code Snippet
Yahaan ek simple process scheduler ka example diya gaya hai, jo C language me likha gaya hai:
Yeh program ek naya process create karta hai aur parent-child process ko run karne ka tareeka dikhata hai.
Conclusion (Summary)
OS Design ka matlab hai OS ka architecture aur structure decide karna.
Implementation me kernel coding, memory management, file system aur device drivers likhna hota hai.
Different architectures ka trade-off hota hai performance, security aur flexibility ke beech.