Processes & Services: Complete Guide for Beginners

 

Processes & services In Operating system – _{Each & everything you should know}

We are often listen about process and service, but don’t know what the concept is, so let’s learn it deeply basically these concept are very important that how computer actually works inside.

In this blog, we will learn about processes and services in easy or understanding English, so that even a beginner can understand them easily.

You must have the basic knowledge about operating systems and programs before learning this topic.

What is a program?

So first of all we are going to talk about program. A program is a set of instruction given to the computer to perform a specific task, program is stored on Hard disk or SSD.

For example user have a chrome browser in pc, Ms Word installed on user’s pc and a calculator in user’s pc, these are all program but they are basically inactive , until user open or run them.

A program doesn’t doing anything by itself until user use a program.

Processes

A process is a running instance of a program. Means a program which start loading into RAM and starts running with the help of the CPU, it becomes a process. Processes are exist only while program is running but when then the program ends and back to inactive state, the process also ends.

A program is inactive when it saved on hard disk (chrome saved on hard disk).It become process when it is active and start using CPU, RAM and other resources.

Process (PID)

Operating system give a unique number to every process Which is called process ID (PID).you can say every process have its unique identity card, with the help of PID operating system can manage multiple processes at the same time.

·        This number helps the operating system to identify each process easily.

·        The operating system can allocate CPU time to process using PID.

·        It also manage memory or each process using PID number.

·        OS track the current state of a process.

·        Also terminate a process when required.

Process states

Every process has different stages. It doesn’t continuously run, even passes from different stages during its life cycle.

New state

In this state, the process is created, when the user click on chrome icon, then the operating system starts processing chrome, allocate the memory and assign a PID to the process, in this moment it is called the new state of process.               

Ready state

In this state, the process is ready to run but waiting for CPU, because only one process can use CPU at a time, therefore others should to be waiting for CPU.

Running state

In this state, the process is actively executed by the CPU. When the CPU gives instructions to the application, means the application is in running state.

Waiting/blocked state

In this state, the process is temporarily stopped or blocked due to some response or waiting for a web page to load from the internet like user input, file loading, internet response late, hardware operations and etc.

Terminated state

In this state, when the user complete it work and close chrome, then the process will ends and move to the terminated state, process getting remove from memory , the process finish execution and operating system release all the resources.

Key points of Process

Its enable multitasking means allow more than one process to run at the same time.

A user open a YouTube, listen a music, or type any kind of document at a same time.

It helps operating system to manage CPU schedule, to allocate memory and handle input/output operations.

Its Improve system efficiency and user experience.

Service

A service is also a process but it is a special type of process which runs in the background and runs silently, background processes are critical for system stability and performance, service cannot open manually but system depends on service, it’s continuously running for system.

It perform the system-level processes, it starts with the system boots and running without any user interaction and continue running for a long time.

In windows service process called services and in Linux/Unix it’s called daemons.

Some types of service process

Window update service

It automatically downloads and install system updates.

Print spooler service

When you print something it automatically manage printing tasks and sends documents to the printer.

Network service

It’s responsible for maintain internet and network connectivity.

Security service

It also protect system from virus’s attacks and malware as background task without user interference.

Differentiate Between Process & Service

Possible Interview Questions to Remember

Define process in operating system?

Answer:

A process is a program which is currently running in the computer’s memory (RAM). It becomes a process when the user chick on any application on system it become process.

 

Differentiate between program & process?

Answer:

Program

·        Passive state

·        Not running

·        Does not use CPU

Process

·        Active state

·        Running on CPU

·        Uses CPU, memory, and I/O devices

 

Elaborate different states of process?

Answer:

·        New state

·        Ready state

·        Running state

·        Waiting / Blocked state

·        Terminated state

 

Elaborate Process ID (PID)?

Answer:

A Process ID is like e identity card or a unique number assigned to every process by the operating system.
It is important for the OS to:

·        Identify and manage process

·        Allocate CPU and RAM

·        Terminate / blocked processes

 

What is a role of service in an operating system?

Answer:

A service is also a process but it is a special type of process which runs in the background and runs silently to process computer operations.

 

Differentiate between a process and a service?

Answer:

Process

·        Usually started by user

·        User can interact

·        Mostly visible

·        Performs user tasks

Service

·        Usually starts automatically

·        No direct user interaction

·        Runs in background

·        Supports system functions

 

Service is also a process or not?

Answer:

Yes, every service is a process, Services basically designed for system-level background tasks, whereas normal processes are for user-level tasks.

 

Give practical examples of a process and a service.

Answer:

Process: user open MS word and start typing it’s a process.

Service: Windows Update running in background is called service.

 

Importance of process in operating system?

Answer:

Processes are important because its:

·        Enable multitasking

·        Efficiently use of CPU and RAM

·        Ensure the proper working of operating system

·        Improve system performance

 

Define Daemons in Linux?

Answer:

Daemons are the Linux services. They are background processes that provide system-level functions.

 

 Define how a process moves between states.

Answer:
User open chrome in system:

New: user click chrome icon , OS creates process

Ready: Waiting for CPU

Running: User start browsing , CPU executes instructions

Waiting: chrome wait for the internet

Terminated: user close chrome , process ends

 

How the OS schedule processes?

Answer:

Operating System uses CPU scheduling algorithms to manage process.

·        First-Come-First-Serve

·        Shortest Job Next

·        Round Robin

·        Priority Scheduling

 

Explain some common errors with processes and services?

Answer:

·        Deadlock: when Two or more processes waiting indefinitely for each other to release resources.

·        Starvation: Low-priority process never gets CPU time.

·        Resource Leak: Process or service holds memory or file handles after termination.

·        Zombie Processes: Finished processes not cleaned by parent.

·         

Is a service different from a daemon?

Answer:

Both run in the background but in different operating systems.

·        Service: Windows

·        Daemon: Linux/Unix

Functionally, both provide system-level tasks without user interaction.

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Conclusion

In conclusion, processes and services are most important part of an operating system. Where a process include program that is currently running using RAM or CPU with the interaction of user. While the service include process that continues runs background and perform system level function without user interaction.

Both work together to maintain system efficient and smooth performance also making the operating system reliable and user-friendly.