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
Distributed Operating System: File System
Distributed File System (DFS) ek aisa system hai jo multiple computers ko ek shared file system provide karta hai. Iska matlab hai ki users bina ye jaane ki files kis server pe store hain, unko access aur share kar sakte hain. DFS location transparency, scalability, aur reliability provide karta hai.
1. Distributed File System ke Features
DFS ke kuch important features hote hain jo ise ek powerful system banate hain:
Transparency: User ko ye nahi pata hota ki file kis system pe store hai, bas file ka naam pata hota hai. Scalability: Bahut saare users aur systems ke sath efficiently kaam karta hai. Reliability: Agar ek system fail ho jaye to data loss na ho. Concurrency: Multiple users ek file ko ek saath access kar sakte hain. Security: Access control aur authentication techniques ka use hota hai.
2. Distributed File System ka Architecture
Distributed File System ke architecture me 3 main components hote hain:
Client: Jo file ko access aur modify karta hai.
Server: Jo file storage aur management ka kaam karta hai.
Storage Devices: Jahan files actually store hoti hain.
Diagram:
Client ek request bhejta hai server ko, jo ki storage device se file ko fetch karke user ko provide karta hai.
3. Naming System in DFS
DFS me file ka ek unique name hota hai jo kisi bhi specific location se independent hota hai.
Location-Transparent Naming: File ka naam fix hota hai, chahe wo kisi bhi server pe ho. Location-Dependent Naming: File ka naam uske location ke according hota hai.
Example:
-
Location Transparent Naming:
/home/user/docs/report.pdf -
Location Dependent Naming:
server1:/data/reports/report.pdf
4. File Access Methods in DFS
DFS me files ko access karne ke alag-alag methods hote hain:
| Method | Description |
|---|---|
| Remote Service Model | File access direct remote server pe hota hai. |
| Upload/Download Model | File pehle client pe download hoti hai, phir changes hone ke baad wapas upload hoti hai. |
Example:
-
Google Drive ek Upload/Download Model use karta hai.
-
Network File System (NFS) ek Remote Service Model use karta hai.
5. File Sharing aur Synchronization
DFS me ek file ko multiple users access kar sakte hain, is wajah se synchronization aur consistency maintain karna important hota hai.
Cache Consistency: Agar ek user file me change kare to wo change doosre users ko bhi dikhe. Locking Mechanism: Ek process ek file ko lock kar sakta hai taaki koi aur usko modify na kare. Version Control: Multiple users ke changes ko track karna.
Example: GitHub ek distributed system hai jo version control ka use karta hai.
6. Fault Tolerance in DFS
Distributed File System me data loss avoid karne ke liye fault tolerance techniques ka use hota hai:
Replication: Ek file ki multiple copies alag-alag servers pe store hoti hain. Backup and Recovery: Data ko automatically backup kiya jata hai. RAID (Redundant Array of Independent Disks): Multiple disks pe data store hota hai taaki ek disk fail hone par bhi data accessible rahe.
Example: Google Drive aur Dropbox replication aur backup techniques ka use karte hain taaki users ka data safe rahe.
7. Security in DFS
Distributed File System me security ek major concern hota hai kyunki data multiple locations pe store hota hai. DFS me security ensure karne ke liye:
Authentication & Authorization: Users ko verify kiya jata hai aur unko limited access diya jata hai. Encryption: Data ko transfer aur storage ke time encrypt kiya jata hai. Access Control List (ACL): Har file aur directory ke liye permissions define ki jati hain.
Example: SSH aur SSL encryption techniques ka use remote file access ke liye hota hai.
8. Popular Examples of Distributed File Systems
Kuch well-known DFS jo widely use hote hain:
| DFS | Description |
|---|---|
| NFS (Network File System) | UNIX/Linux me commonly use hone wala DFS. |
| AFS (Andrew File System) | Secure aur scalable DFS jo universities aur enterprises me use hota hai. |
| Google File System (GFS) | Google ke large-scale data storage ke liye optimized DFS. |
| HDFS (Hadoop Distributed File System) | Big Data aur cloud computing applications me use hota hai. |
Conclusion
Distributed File System ek scalable, secure aur fault-tolerant system hota hai jo multiple users ko file access aur sharing ki facility deta hai bina kisi location ki limitation ke. Google Drive, Dropbox, NFS, aur HDFS jaise DFS real-world me kaafi use hote hain.