If you’re anything like me, you have at least 20 browser tabs open, along with a couple of spreadsheets and probably some music.
Ever wonder how your computer never runs out of memory or storage while running all these programs? Everyone’s had computers freeze, but generally, they’re good at responding to input. Thanks to operating systems (OS), we can communicate with them even though we don’t know how to speak their language.
An operating system is a program that, following the boot program, manages all computer applications. Application programs request services from the operating system using application programming interfaces (APIs). Users rely on user interfaces such as a command-line interface (CLI) or graphical user interface (GUI) to interact with the operating system.
Software users and developers love operating systems because of two reasons. First, an operating system doesn’t rely on the application’s UI. Second, operating systems can easily manage computers’ low-level functionalities, including network interfaces and disk storage. Without an operating system, applications must feature UIs, resulting in larger application sizes and challenging software development.
What is an operating system (OS)?
An operating system is software that manages a computer's hardware and software resources, enabling users and applications to interact with the system. It handles tasks like resource allocation, process management, file storage, device communication, and security. Common examples include Windows, macOS, Linux, Android, and iOS.
Today, operating systems leverage device drivers to provide hardware environment-specific services. When an application calls the storage device, the operating system uses the corresponding driver to convert the call into commands that the underlying hardware needs. Since all applications access the same resources and services, operating systems can service countless applications.
Computers typically come pre-loaded with the following general-purpose operating systems, but you can also upgrade them.
- Microsoft Windows has been behind home and business computers for years. It comes pre-loaded on the majority of personal computers. After making the first version available in the 1980s, Microsoft launched different versions of Windows, including popular ones like Windows 7 and Windows 10.
- macOS is another popular operating system available on Apple’s Macintosh computers. Popular versions include macOS Sierra for desktops and Apple iOS for mobiles.
- Oracle Linux is a free, open-source operating system popular among software developers and business intelligence professionals.
If you want to learn more about how operating systems manage software and hardware resources, this article is for you.
Operating systems are the most essential software on your computer. Whether you play computer games or use Microsoft 365 applications, every program needs an environment to run and perform its intended job. Operating systems ensure efficient use of hardware, making computer systems convenient to use.
Operating system features
- Security management uses firewall and authorization keys to prevent malware attacks.
- Process management communicates and synchronizes multiple processes without time delay.
- Storage and memory management allocates and deallocates memory to and from processes to prevent overload.
- Disk management names, shares, retrieves, protects, and stores file systems and device drivers.
- Device management tracks how users utilize system hardware for different jobs.
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Loading and execution interpret and process commands to run programs.
I/O operations hide hardware specifics from end-users for easy device usage.
Time to dive deep into the functions of an operating system.
What are the functions of an operating system?
So now you know that an operating system acts as an interface between computer hardware and software. It performs some basic jobs like booting your device, shutting it down, and managing its files, but there’s more than meets the eye. Check out the common operating system functions below.
Main functions of an operating system
- Monitors system health.
- Manipulates and stores data
- Handles input/output operations
- Executes user programs or system programs
- Spots system errors to prevent computer system malfunctioning
- Prevents unauthorized access and protects user data with passwords
- Improves response time between service requests and system response
- Assigns interpreters, assemblers, compilers, and other software to users
File management
File management involves creating, opening, closing, updating, deleting, and organizing files and directories. Operating systems also define user role and access management. For example, you may want to keep a file with read-only permission so unauthorized users can’t edit or delete it.
Device management
Most users rely on peripheral devices like mice, printers, and keyboards to input information into their computers. In turn, these hardware devices rely on their respective drivers to function. An operating system uses an input/output (I/O) controller to manage those device drivers and keep your devices connected to your computer.
Operating systems also control how these devices behave. For example, you may want to move the mouse one screen at a time, but you won’t be able to do that unless an OS lets you change device settings. Moreover, an OS enables you to install device updates and allocate devices to certain processes.
Process management
It doesn't matter whether you’re creating a dashboard or playing a game – everything you do on your computer is a process. Operating systems go into multi-tasking mode when you do multiple things at the same time. They synchronize the processes and offer them the necessary resources. An OS also deallocates resources once a process is complete.
How does an operating system manage all processes?
An operating system uses process scheduling and resource allocation to manage all processes. Every process gets a time slice or quantum – a certain amount of time – to complete execution. Once a process uses its quantum, another process gets its turn to execute. This way, every process gets CPU time for execution with the help of device memory.
Memory management
When you turn on a computer, the operating system loads itself into memory to allocate memory to programs. The primary or main memory consists of large word or byte arrays, each with an address.
An OS tracks how different applications are using these memory bytes. The ultimate aim is to ensure that no single application or process takes up too much memory space and slows down your machine. Operating systems can also move data around and delete files to create space for processes.
A multiprogramming OS executes numerous applications on a single processor computer. These operating systems decide the order in which processes get to access memory. The OS deallocates the memory at the end of a process or while performing an I/O operation.
Job accounting
Operating systems track computer resource usage as well. Having a bird’s eye view of which applications are using which resources means you can troubleshoot performance issues or even spot unauthorized software installations. Moreover, system administrators use job accounting to track system usage, problematic processes, and billing, all based on resource usage.
Did you know? Operating systems use job scheduling algorithms like shortest-job-next (SJN), round robin (RR), first come, first serve, and priority scheduling to prioritize and allocate system resources to different tasks.
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Types of OS
Let’s go over some of the most popular operating system types.
1. Batch operating system: This operating system processes jobs that share the same requirements as “batches.” It executes each job on a first-come, first-served basis. These operating systems rely on operators to group similar jobs. Payroll systems or bank statements use these operating systems.
2. Time-sharing operating systems: Also known as multitasking systems, time-sharing operating systems give each task a certain amount of time for execution. At the end of the time interval, the OS moves to the next task. Common time-sharing operating system examples include Multics and Unix. These operating systems cut down on idle time since each process gets an equal opportunity for execution.
3. Distributed operating systems: These are collections of interconnected computer nodes that share a communication network with each other. Loosely coupled or distributed systems rely on different autonomous computers and CPUs to execute jobs. LOCUS is a distributed operating system developed at the University of California, Los Angeles (UCLA) in the 1980s.
4. Network operating systems: These manage networking functions, applications, and security over private networks. Also known as tightly coupled systems, this type of OS depends on centralized servers to offer users shared access to files, security, and printing, among other functions. You can also remotely integrate new hardware and technologies into the server system. Microsoft Windows Server 2003 is a network operating system.
5. Real-time operating systems (RTOS): A real-time operating system switches between multiple individual programming tasks using a single processing core. The time interval or response time necessary to process input is shorter. As a result, you can rapidly switch between tasks. RTOS is different from the operating systems you use every day. Time-bound processes like air traffic control systems, missile operations, and network multimedia systems use RTOS.
Types of real-time operating systems (RTOS)
- Hard real-time systems ensure critical task completion under a time limit. They don’t come with virtual memory and are suitable for processes when even the shortest delay is unacceptable. For example, airbags use hard RTOS.
- Soft real-time systems offer some time-limit relaxation and use scheduling processes to execute tasks independently. For example, multimedia or digital audio systems use soft RTOS.
- Firm real-time systems follow deadlines to avoid unintended consequences. Multimedia applications use firm RTOS to render and deliver data.
6. Mobile operating systems: A mobile OS powers wearable devices, tablets, smartphones, and other handheld digital devices. Android and Apple iOS are the two most commonly used mobile operating systems.
Now, we’ll look at various components that help an OS perform tasks.
Components of an operating system
While most operating systems have different structures, they use similar components to perform logical operations. Check them out below.
- Process management deals with multiple simultaneous processes running on an operating system. An OS allocates memory to applications so that they run efficiently. Process management activities include creation, suspension, resumption, synchronization, and communication.
- I/O device management hides hardware specifics from users. Instead, it gives users abstract details for ease of usage. This component, which provides device driver code and manages device memories, is also responsible for the system’s buffer cache (a memory resource that mediates data transfer.
- File management involves managing mass storage devices (think hard drives or hard disks) and organizing their contents for accessibility. An OS performs various file management activities such as directory creation and deletion, file manipulation, and backup.
- Network management is the process of managing and administering a computer network. An OS may perform service quality maintenance, fault analysis, network security management, and performance monitoring functions.
- Main memory management maximizes a computer system’s memory utilization by offering fast storage to a CPU. Main memory is a large array of storage with an address, but it can lose content in case of system failure or power shutdown. Memory management helps an OS track memory usage and load new processes when memory becomes available.
- Secondary storage management backs up main memory and aids in process execution. Most computers use disks to store data for programs like formatters, compilers, and assemblers. These programs are stored on disk until they are loaded into memory. Common disk management activities include disk scheduling, storage allocation, and free space management.
- Security management ensures every program, process, or user accesses authorized resources only. For example, hardware memory can only execute tasks within its own address space. This mechanism uses a timer to prevent processes from gaining CPU control. Security management also prevents processes from running their own I/O devices.
- Command interpreter system calls on one or more system programs to execute user commands. Control statements often give these commands to the operating system. Programs then read and interpret control statements for automatic execution.
What is kernel and how does it function?
A kernel is a central component of an OS that manages hardware and software resources most efficiently. It tracks disk usage, handles memory, controls task management, manages interruptions, and facilitates input/output communication.
Operating system kernels also offer drivers for printers, storage devices, monitors, keyboards, and network adapters. Most kernels are launched under the general public license (GPL), also known as GNU, meaning you can freely copy, modify, or distribute them.
Operating system advantages
You can’t run a computer system without an OS, but specifically, how do operating systems benefit you? A good OS:
- Acts as an interface between users and computer hardware. An operating system lets you input data, perform operations, and get the desired results. No matter the complexity of a task, an OS helps you communicate with a computer system without you having to speak its language.
- Shares resources among multiple users and devices. You can share server resources with modems, fax machines, and printers, and other users can share information with you via mail and apps.
- Doesn’t require you to write code. As operating systems use graphical user interfaces (GUIs), you don't need to hire programmers or know programming languages to execute tasks.
- Protects data with user authentication. Modern operating systems use multiple authentication processes such as biometric verification, username and password, or physical object authentication to prevent unauthorized data access.
- Keeps systems up-to-date. Operating systems also protect your system from evolving virus attacks and bugs with frequent update rollouts.
- Lets you perform multiple tasks at once. You can easily multitask and interact with different computer programs simultaneously, thanks to CPU scheduling and multiprogramming.
What are the disadvantages of an operating system?
- OS crash or system failure occurs because of viruses, buggy device drivers, and malware. These types of crashes cause the entire system to fail.
- Complex OS-applied language means you’ll have difficulty understanding issues and resolving them on your own.
- Fragmentation happens when free memory space breaks into smaller chunks. Some chunks may be so small that they can’t handle processes. Internal fragmentation happens when the process exceeds the memory size. External fragmentation happens when there’s still space in the memory block after memory allocation.
- High price tags can come as a shock when you want a user-friendly OS instead of the free ones.
- Virus attacks can slow down your system or stop it from being functional, which is why it’s best to use antivirus software.
Best operating systems in 2024
The best operating systems make it easy for you to run simultaneous programs while managing CPU, software, and hardware. Check out the top operating systems below.
To be included in this category, an operating system software must:
- Run applications simultaneously
- Manage device software and hardware
- Work with the CPU to allocate memory and storage
*These top five leading operating systems come from G2’s Fall 2024 Grid® Report. Some reviews may be edited for clarity.
1. Windows 11
Windows 11 is the latest OS from Microsoft, designed with a fresh look and feel to improve user productivity and creativity. Featuring a redesigned Start Menu, enhanced virtual desktops, and snap layouts, Windows 11 offers a streamlined user experience.
What users like best:
"What I like best about Windows 11 is its modernized user interface and enhanced productivity features. The centered Start Menu and taskbar create a cleaner, more organized look, while the Snap Layouts feature significantly improves multitasking capabilities. Additionally, the overall performance improvements make the system feel faster and more responsive, providing a smoother user experience."
— Windows 11 Review, Nilesh C.
What users dislike:
"One thing I have noticed since I upgraded to Windows 11 is that my RAM got almost full. It's taking more computing time than Windows 10, which sometimes results in Windows crashes.
— Windows 11 Review, Deepesh S.
2. Windows 10
Windows 10 from Microsoft is a leading operating system that’s easy to use, safe, and integrable.
What users like best:
“It’s a nice GUI-based operating system with all the functionality required for day-to-day tasks. It has a good support facility and is also really good for gaming. I liked the driver support for all kinds of devices. Microsoft Office is the best application Microsoft ever created.”
— Windows 10 Review, Ujjwal A.
What users dislike:
“Some unwanted applications get automatically installed, which is a privacy problem. Older programs and games may no longer work on this latest Windows operating system from Microsoft.”
— Windows 10 Review, Syed Khalid M.
3. Apple iOS
Apple iOS is an advanced mobile OS that powers Apple mobile devices. It features a straightforward interface and robust security.
What users like best:
“The security measures that are already built into iOS make it one of the most powerful platforms. Users can rely on it to complete daily chores and save private information with confidence.”
— Apple iOS Review, Adnan S.
What users dislike:
“The price point is pretty high, which is understandable, but their hardware could stand to be a little more robust. I also hated that they did away with the headphone jack years ago, but that is a small gripe.”
— Apple iOS Review, Amanda R.
4. Chrome OS
Chrome OS, developed by Google, is a lightweight operating system specifically designed for simplicity, speed, and security. It is built around the Chrome browser and uses cloud-based applications, making it an ideal choice for users who depend heavily on web services.
What users like best:
"I appreciate the seamless experience that Chrome Settings and profiles offer, as they are effortlessly synchronized across devices. The ability to log into any Chrome device using my Google account and instantly pick up where I left off within seconds is a game-changer."
— Chrome OS Review, Frantz C.
What users dislike:
"Some Google web applications fail to run on this OS. Real-time integration is quite a time-consuming task in Google OS. It has a very limited storage of 15 GB, which could have been more for the users."
— Chrome OS Review, Shantanu R.
5. Red Hat Enterprise Linux
Red Hat Enterprise Linux (RHEL) is a leading enterprise operating system renowned for its performance, security, and stability. Developed by Red Hat, RHEL is designed for use in various environments, from cloud deployments to traditional data centers.
What users like best:
"Redhat, AKA RHEL, is the best Linux OS environment that anybody can use in their enterprise environments. It is mostly because of the support and security it provides. It frequently provides patches for all the identified bugs and can be used to deploy, test, and modify any kind of Linux-based package easily. You can deploy this OS using very low hardware resources, and if you are a CLI lover, this is the product that you need to choose."
— RHEL Review, Dulana R.
What users dislike:
"It's not easy to install with documents only. Handling packages, permissions, and errors is difficult. Identifying the dependencies of certain packages and finding their dependencies could be simpler."
— RHEL Review, Asif A.
Choose what’s right for you
Knowing your needs is important before choosing an operating system from the many open-source, free, and paid options available. A developer has different requirements than a gamer. Regardless of what you do, pick an operating system that manages memory, protects your privacy, and fits your budget.
Using computers or mobile devices for online work? Be wary of spyware and protect your online privacy.
This article was originally published in 2023. It has been updated with new information.
Sudipto Paul
Sudipto Paul is a Sr. Content Marketing Specialist at G2. With over five years of experience in SaaS content marketing, he creates helpful content that sparks conversations and drives actions. At G2, he writes in-depth IT infrastructure articles on topics like application server, data center management, hyperconverged infrastructure, and vector database. Sudipto received his MBA from Liverpool John Moores University. Connect with him on LinkedIn.
