Operating System Tutorial

Operating System Tutorial Types of Operating System Evolution of Operating System Functions of Operating System Operating System Properties Operating System Services Components of Operating System Needs of the Operating System

Operating Systems

Linux Operating System Unix Operating System Ubuntu Operating System Chrome Operating Systems Fedora Operating System MAC Operating System MS Windows Operating System Solaris Operating System Cooperative Operating System CorelDRAW Operating System CentOS FreeBSD Operating Systems Batch Operating System MS-DOS Operating System Commercial Mobile Operating Systems


Difference Between Multi-programming and Multitasking Difference between C-LOOK and C-SCAN Difference between Rotational Latency and Disk Assess Time Trap vs Interrupt Difference between C-SCAN and SSTF Difference between SCAN and FCFS Difference between Seek Time and Disk Access Time Difference between SSTF and LOOK Difference between Process and Program in the Operating System Difference between Protection and Security in Operating System

How To

How to implement Monitors using Semaphores How to Install a Different Operating System on a PC


What is Kernel and Types of Kernel What is DOS Operating System What is Thread and Types of Thread What is Process Scheduler and Process Queue What is Context Switching What is CPU Scheduling What is Producer-Consumer Problem What is Semaphore in Operating System Monitors in Operating System What is Deadlock What is Paging and Segmentation What is Demand Paging What is Virtual Memory What is a Long term Scheduler What is Page Replacement in Operating System What is BSR Mode What is Convoy Effect What is Job Sequencing in Operating System Why is it critical for the Scheduler to distinguish between I/O-bound and CPU-bound programs Why is there a Need for an Operating System


Process Management Process State Scheduling Algorithm FCFS (First-come-First-Serve) Scheduling SJF (Shortest Job First) Scheduling Round-Robin CPU Scheduling Priority Based Scheduling HRRN (Highest Response Ratio Next) Scheduling Process Synchronization Lock Variable Mechanism TSL Mechanism Turn Variable Mechanism Interested Variable Mechanism Deadlock Avoidance Strategies for Handling Deadlock Deadlock Prevention Deadlock Detection and Recovery Resource Allocation Graph Banker’s Algorithm in Operating System Fixed Partitioning and Dynamic Partitioning Partitioning Algorithms Disk Scheduling Algorithms FCFS and SSTF Disk Scheduling Algorithm SCAN and C-SCAN Disk Scheduling Algorithm Look and C-Look Disk Scheduling Algorithm File in Operating System File Access Methods in Operating System File Allocation Method Directory Structure in Operating System N-Step-SCAN Disk Scheduling Feedback Queue in Operating System Contiguous Memory Allocation in Operating System Real-time Operating System Starvation in Operating System Thrashing in Operating System 5 Goals of Operating System Advantages of Operating System Advantages of UNIX Operating System Bit Vector in Operating System Booting Process in Operating System Can a Computer Run Without the Operating System Dining Philosophers Problem in Operating System Free Space Management in Operating System Inter Process Communication in Operating System Swapping in Operating System Memory Management in Operating System Multiprogramming Operating System Multitasking Operating Systems Multi-user Operating Systems Non-Contiguous Memory Allocation in Operating System Page Table in Operating System Process Scheduling in Operating System Segmentation in Operating System Simple Structure in Operating System Single-User Operating System Two Phase Locking Protocol Advantages and Disadvantages of Operating System Arithmetic operations in binary number system Assemblers in the operating system Bakery Algorithm in Operating System Benefits of Ubuntu Operating System CPU Scheduling Criteria in Operating System Critical Section in Operating System Device Management in Operating System Linux Scheduler in Operating System Long Term Scheduler in Operating System Mutex in Operating System Operating System Failure Peterson's Solution in Operating System Privileged and Non-Privileged Instructions in Operating System Swapping in Operating System Types of Operating System Zombie and Orphan Process in Operating System 62-bit operating system Advantages and Disadvantages of Batch Operating System Boot Block and Bad Block in Operating System Contiguous and Non - Contiguous Memory Allocation in Operating System Control and Distribution Systems in Operations Management Control Program in Operating System Convergent Technologies in Operating System Convoy Effect in Operating System Copy Operating Systems to SSD Core Components of Operating System Core of UNIX Operating System Correct Value to return to the Operating System Corrupted Operating System Cos is Smart Card Operating System Cosmos Operating Systems Examples Generation of Operating System Hardware Solution in Operating System Process Control Block in Operating System Function of Kernel in Operating System Operating System Layers History of Debian Operating Systems Branches and Architecture of Debian Operating Systems Features and Packages of Debian Operating Systems Installation of Operating System on a New PC Organizational Structure and Development in Debian Operating Systems User Interface in Operating System Types Of Memory in OS Operating System in Nokia Multilevel Paging in OS Memory Mapping Techniques in OS Memory Layout of a Process in Operating System Hardware Protection in Operating System Functions of File Management in Operating System Core of Linux Operating System Cache Replacement Policy in Operating System Cache Line and Cache Size in Operating System What is Memory Mapping? Difference Between Network Operating System And Distributed Operating System What is the difference between a Hard link and a Soft Link? Principles of Preemptive Scheduling Process Scheduling Algorithms What is NOS? What is the Interrupt I/O Process? What is Time Sharing OS What is process termination? What is Time-Sharing Operating System What is Batch File File system manipulation What is Message-passing Technique in OS Logical Clock in Distributed System

Bit Vector in Operating System

What is Bit vector?

Bit vector is one of the most important methods used in the free space management of operating system. Free space management which is used by the operating system leads the free space in the hard disk that’s why we call it free space management. OS generally leads a free space list to keep the track of free space disk. Free space list contains all disk blocks which are not allocated to any file or directory.

Bit vector in Operating System

What is Bit?

Bit is also known as unit of information used in computing which can have only one of two values either 1 or 0.

Bit vector also known as bitmap is generally used to implement the free space list. In this method, every block symbolizes of a bit (0 or 1). Condition 1, when a block has bit 0 means block is allocated. Condition 2, when block have 1 bit which means block is free or no memory allocation. It refers to the special type of indexing which use bitmaps. This method is generally used for big databases.

  1. A bit vector size is identical to the number of disks blocks is used.
  2. If ith block is free then the bit vector value at ith location will be 0, otherwise 1.
  3. Memory requirements for storing the bit vectors also increase with the increase in size of the disk.

Advantages of Bit vector

Advantages of bit vector are as follows:

  1. It is simple and easy to understand.
  2. It consumes less memory.
  3. It is well organized to find free spaces.

Disadvantages of Bit vector

Disadvantages of bit vector are as follows:

  1. OS goes through all the blocks until it finds a free block.
  2. To find free block, OS may need to search the whole bit vector.
  3. It requires some special hardware support in some conditions.

Need of Bitmap

Now, we take an example to explain the working of bitmap. Assume that there is a company which holds an employee table with entries like empno, empname, designation, income etc. As we all know employees in any organization are hired once in a year which means the table is less updated and endure static most of the time. But the columns will always concurrent used in queries to retrieve data like: no of female candidates in the company and many more. In this situation, we need a method which is known as a file organization method which is capable enough to provide quick results. But any of the traditional file organization method is not that fast to provide quick results. Therefore, we switch better method of storing and retrieving data known as bitmap indexing.


The bitmap has number of applications in areas where the space as well as the efficiency is at premium. Most commonly, they are used to represent a simple group of Boolean flags or an ordered sequence of Boolean values.

  1. They are used for the priority queues, where the bit at index k is set if and only if k is in the queue.
  2. They are also used for the allocation of memory pages, disk sectors etc. In such cases term bitmap may also use. This term is generally used to refer to raster images which use multiple bit or pixel.
  3. Bloom filter which is one of the most important type of application of bitmaps. It is used to store the huge sets in small space in exchange for a small probability. It is also possible to build probabilistic hash tables based on bit arrays which accepts false positive or negatives.
  4. They are also a useful abstraction for examining the streams of compressed data, which often contain element that occupy portions of bytes or are not byte aligned, for example the compressed human coding representation of a single 8-bit character can be anywhere from 1 to 255 bits along.
  5. Bit maps and operations on them are also important for developing the succinct data structures, which is close to the minimum amount applicable space. In this context, operations like searching the nth bit up to the certain position become important.