Windows Operating System: A Case Study

Regardless of the type of operating system, all computer operating systems performs the following main tasks:

 Process Management

 Memory Management

 File System Management

 Device Management

Process management

Process is defined as an instant of a computer program that is being executed or in other words a program in execution. Application software being executed by user or a printing task carried out by the system are considered as processes.

Below is the image of processes running on windows operating system:

All processes go through 5 states described as:

Initiation – the creation stage of the process.

Ready – the stage where all the necessary resources required to execute the process are available and waiting for the CPU to start

When the process ends all the system resources are freed up.

Most modern computer operating systems runs multiple processes at one time in comparison to earlier ones which supported only one program at one time by allowing the CPU to switch from one process to another, and this method is known as context switching.

Since most modern computer operating systems supports multiple processes, in a place where more than one program run concurrently, the need for further allocation of system resources led to the problem of deadlock. Deadlock is defined permanent blocking of a set of processes that are competing for computer resources.

The four factors that led to deadlock are:

 Mutual exclusion; this occurs when one process is using system resources at a time.

 Hold and wait; this occurs when a process holds the resources allocated to it while waiting for further resources to be allocated to

It’s a technique that co-ordinate activities in which multiple processes compete for system resources. A semaphore is an integer value which define wait and signal operations. Depending on the value, the process can either use resources or wait for a period of time before accessing them. When a process uses the resources or finish using the resources changes the value to reflect it to others semaphore users.

Memory management

Main memory is fundamental to the running of most computer systems as CPU can only load instructions from here for program to run. Main memory also referred to as Random Access Memory or RAM acts as a source data for CPU and other devices. Since main memory is volatile and can not hold data permanent, programs must be loaded and re-loaded when not in use.

In relation to memory management, operating system keeps records of the part of the memory that is being used and the program that use it and decide which program to move in and out of memory and therefore assigning and freeing up of memory space.

Operating system is responsible for mapping out the logical addresses and physical addresses when assigning memory space to programs. There are several mechanisms that the operating system uses in memory