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

Memory Layout of a Process in Operating System

The layout of the memory of a specific process is done so that the Operating system can easily access and perform given actions on the code or program at a particular instance. This way of organising the memory is done in multiple separate modules or components, which include the source code, the data, the stack, and the heap. These modules are organised in a particular memory layout inside the virtual address of the process. The layout of this memory can be different from the other, because of the operating system that we are working on. 

Different components sum up the memory layout. They are:

  1. Text segment
  2. Data segment
  3. Heap
  4. Stack

These individual components will make a proper layout and then helps in the execution of the code correctly.

1. Text segment

The text segment contains the source code which a user works on. This may contain a variety of text or code in the memory within the sections of the program. These contain the operations or commands that are executable. Since this is a memory space, the text segment will be placed at the bottom of the heap and stack. This is done to prevent the heap or stack from overflowing with the data which we enter. 

Generally, the text segment is transferable, which means only a single copy of the data or code is enough in the memory which can be called and executed at any time. But the data or code in the text segment is limited only to readable types of data, and this is done to prevent overwriting additional instruction in the original data, which makes the data altered and ambiguous.

Memory Layout of a Process in Operating System

2. Data segment

The data segment basically consists of the global variables and the static variables from the code. This is the central portion of the address space of a program virtually. There are two types in the data segment.

  • Initialised data segment: In this type of data segment, it contains only the initialised global and static variables from the code which are initialised by some specific values at the start of the program. The data segments are not specified only for read mode, because the data can be altered in this segment in the run time. The initialised data segment contains a designated space for the storage of the variables and other access specifiers from the program, which are used at the time of execution. Some of the initialised data include variables, integers, float values, arrays, etc.
  • Uninitialized data segment: The uninitialized data segment is also called as bss, which is named after the block started by symbol. The data in this segment are initialised by the kernel of the operating system to 0 prior to the start of the program. This contains the global variables along with the static variables, and these variables are also set to 0.

This data segment will not store the variables with their initial values, which is done in the initialised data segment. This data segment helps reduce the size of the program by allocating the memory to the OS without redundancy of values.

3. Heap

The heap is a segment in this memory layout that is responsible for dynamic memory allocation. This is done during the program execution; this uses the allocated memory to fulfil the needs. The heap provides the extensible and resizable type of memory for storing the data, objects, and arrays, strings. This allows the program to request the memory at the run time of the code, by using the functions like mallocand deallocate. These are used to assign dynamic memory in the code for better execution. These functions are used in languages such as C and C++. This enables the flexibility in the code and adds the functionality of the heap data structure. 

This provides better memory arrangements and accessing the memory is made easy, reducing the time and resources. The heap segment is a valuable and a better way to access the memory for dynamic memory management.

4. Stack

The stack is also one of the segments in the memory layout, which is used primarily for managing the function calls in the source code. The stack is automatically managed by the compiler at the runtime environment, and this makes sure that the memory that is being allocated is again deallocated correctly at the right time. The stack pointer, is a very useful register in this segment that helps keep the track of the memory being transferred. The stack follows a LIFO manner which means Last in First out. This means that the stack will delete the data which is recently entered or is last entered among all. This follows two operations, Push and Pop, which means removing and entering the data, respectively. 

Because of a fixed memory size, this defines the start of the program. If there are more push operations, then there is a chance of stack overflow, which results in data loss. This ultimately results in system crashes and many more. It is vital to keep a track of the data that is being allocated to the stack as it is of a fixed size.