Study Material

  🔴 UNIT 5 – SHELL PROGRAMMING & FILTER COMMANDS 🟢 1. Introduction to Shell ✅ What is a Shell? A Shell is a command-line interpreter that: Accepts user commands Executes them Acts as an interface between user and OS 🔹 Types of Shells in Linux Shell Description sh Bourne shell bash Bourne Again Shell (most used) csh C shell ksh Korn shell zsh Advanced shell 👉 Bash is most commonly used. 🟢 2. Shell Programming ✅ Definition Shell programming is writing a script to automate tasks using shell commands. 🔹 Advantages ✔ Saves time ✔ Automates tasks ✔ Easy to write ✔ Used in system administration 🟢 3. Structure of Shell Script #!/bin/bash echo "Hello World" Explanation: #!/bin/bash → Shebang line echo → Print output 🔹 Running a Shell Script chmod +x file.sh ./file.sh 🟢 4. Variables in Shell User Defined Variable name= "Amit" echo $name System Variables $HOME $USER $PATH 🟢 5. Read Command echo ...

  🔴 UNIT 4 – UNIX & LINUX COMMANDS 1️⃣ Introduction to UNIX / Linux ✅ UNIX UNIX is a multi-user, multitasking operating system developed at AT&T Bell Labs. ✅ Linux Linux is an open-source UNIX-based operating system . 🔹 Features of Linux ✔ Open source ✔ Secure ✔ Portable ✔ Multi-user ✔ Multitasking 2️⃣ Linux File System Structure Directory Purpose / Root directory /bin System commands /etc Configuration files /home User files /usr User programs /var Variable files /tmp Temporary files 3️⃣ Basic Linux Commands 📁 Directory Commands Command Description pwd Show current directory ls List files cd Change directory mkdir Create directory rmdir Remove empty directory 📄 File Commands Command Description touch Create file cat View file cp Copy file mv Move/rename file rm Delete file file File type 📘 Viewing Files Command Use more View page by page less Scrollable view head First 10 lines tail Last 10 lines 4️⃣ File Permission Commands Permission T...

  🔴 UNIT 3 – FILE SYSTEM & I/O MANAGEMENT 1️⃣ File System – Introduction ✅ What is a File? A file is a collection of related information stored on secondary storage. ✅ File System The file system is a method used by the OS to: Store files Retrieve files Organize data efficiently 2️⃣ File Attributes Each file has the following attributes: Attribute Description Name File name Type File extension Size File size Location Disk location Protection Access rights Time & Date Creation/modification time 3️⃣ File Operations Common file operations: ✔ Create ✔ Open ✔ Read ✔ Write ✔ Close ✔ Delete 4️⃣ File Access Methods 🔹 1. Sequential Access Data accessed sequentially Example: Text file ✔ Simple ❌ Slow for random access 🔹 2. Direct Access Access any record directly Example: Database files ✔ Fast ✔ Efficient 🔹 3. Indexed Access Uses index to locate data Combination of sequential & direct 5️⃣ Directory Structur...

  🔴 UNIT 2 – MEMORY MANAGEMENT 1️⃣ Memory Management – Introduction ✅ Definition Memory management is the function of the OS that: Allocates memory to processes Deallocates memory after use Manages primary and secondary memory efficiently 2️⃣ Memory Management Requirements ✔ Relocation ✔ Protection ✔ Sharing ✔ Logical organization ✔ Physical organization 3️⃣ Memory Management Techniques 🔹 1. Multiprogramming with Fixed Partitions Concept: Memory is divided into fixed-size partitions One process per partition Advantages: ✔ Simple ✔ Easy implementation Disadvantages: ❌ Internal fragmentation ❌ Wastage of memory 🔹 2. Multiprogramming with Variable Partitions Concept: Memory allocated as per process size No fixed partitions Advantages: ✔ Less internal fragmentation Disadvantages: ❌ External fragmentation 4️⃣ Memory Allocation Strategies 🔹 First Fit Allocates first available memory block ✔ Fast ❌ Fragmentation 🔹 Best...

  📘 PAPER 5 – OPERATING SYSTEM 🔴 UNIT 1 – INTRODUCTION & PROCESS MANAGEMENT 1️⃣ Introduction to Operating System ✅ What is an Operating System (OS)? An Operating System is system software that: Acts as an interface between user and hardware Manages computer resources Controls execution of programs ✅ Functions of Operating System ✔ Process management ✔ Memory management ✔ File management ✔ Device management ✔ Security & protection ✔ User interface ✅ Examples of Operating Systems Windows Linux macOS Android UNIX 2️⃣ Types of Operating Systems 🔹 1. Batch Operating System Jobs executed in batches No user interaction 🔹 2. Multiprogramming OS Multiple programs in memory CPU utilization increases 🔹 3. Time Sharing OS Multiple users at same time CPU shared among users 🔹 4. Real-Time OS Immediate response Used in medical & industrial systems 3️⃣ Structure of Operating System 🔹 Layered Str...