How Do Operating Systems Work?

Summary

This video script explores the evolution and importance of operating systems (OS) in modern computing. It starts with the early days of punch card programming and moves through the development of the OS, which standardized tasks across different hardware, allowing for efficient resource management and user interaction. The script explains the kernel's role, memory management with RAM and virtual memory, device control through drivers, and the shift from command-line to graphical user interfaces. It concludes by emphasizing the OS as the core that interacts with hardware, manages programs, and facilitates user engagement.

Takeaways

• 💻 **Operating System (OS)**: The OS is the program that integrates all hardware and software components of a computer.
• 🚀 **Evolution of Computing**: Early computers performed 5,000 calculations per second, whereas today's supercomputers can perform up to 34 trillion calculations per second.
• 📚 **Punch Cards**: Early programs were written on punch cards that were fed into the CPU for batch processing.
• 🔄 **Resource Management**: The OS manages and allocates resources such as RAM and devices like printers.
• 🔀 **Multitasking**: The OS enables multitasking by allowing time slicing, which lets multiple programs run on the CPU simultaneously.
• 💾 **Memory Management**: The OS controls RAM, which is used for running applications, and differentiates it from secondary memory like hard disks.
• 🔐 **Virtual Memory**: The OS uses virtual memory to extend the limited RAM by temporarily moving data to the hard disk and protecting memory from being overwritten.
• 🖨 **Device Drivers**: The OS loads device drivers to manage and communicate with external devices, allowing for a more universal programming approach.
• 🎛️ **User Interface**: The OS provides a user interface, evolving from command-line to graphical user interfaces (GUIs), making computers more user-friendly.
• 🌐 **Types of OS**: There are various types of operating systems like Mac OSX, Linux, Windows, iOS, and Android, each serving different computing needs.

Q & A

What is the primary function of an operating system?

An operating system's primary function is to manage and allocate computer resources, control hardware, and provide an interface for user interaction.

How did early computers handle tasks before the invention of operating systems?

Early computers used punch cards for batch processing, with a person responsible for feeding the cards into the CPU and managing the process.

What is the CPU and what does it do?

The CPU, or central processing unit, is the part of the computer that performs calculations, processes information, receives input, and produces output.

What is the role of the kernel in an operating system?

The kernel is the core of the operating system, acting as an intermediary that allows software applications to access the computer's hardware.

How does an operating system manage memory?

Operating systems manage memory by controlling where and how data is stored in RAM, using virtual memory to extend the available memory space when needed, and providing protected memory to prevent data corruption.

What is the difference between RAM and storage?

RAM, or Random Access Memory, is primary storage used by the CPU to run applications and is volatile, meaning it loses data when the computer is turned off. Storage, often a hard disk, is secondary memory that retains data even when the computer is off.

What is virtual memory and why is it important?

Virtual memory is a feature of operating systems that compensates for the limited amount of RAM by temporarily transferring data to hard disk storage, making it appear as if there is more RAM available.

How do device drivers help in operating systems?

Device drivers are pieces of software that allow the operating system to communicate with and control external devices. They translate general instructions into specific commands that the devices can understand.

What is a command line interface and how does it work?

A command line interface is a text-based method of interacting with an operating system where users type in commands to perform tasks. It requires knowledge of specific commands to operate.

How has the graphical user interface changed the way users interact with computers?

The graphical user interface introduced icons and a mouse, allowing users to interact with computers through visual elements and drag-and-drop actions, making it more intuitive and user-friendly.

What are some modern ways of interacting with computers mentioned in the script?

Modern ways of interacting with computers include touchscreens and virtual reality, offering more intuitive and immersive user experiences.

Outlines

00:00

💻 The Birth and Evolution of Operating Systems

The paragraph discusses the evolution of computers from early machines capable of 5,000 calculations per second to modern supercomputers performing trillions of calculations. It highlights the invention of punch cards for programming and the challenges faced due to the variety of computer resources and the need for machine-specific programming. The paragraph introduces the concept of the operating system (OS) as a solution to unify these tasks and resources, explaining how the OS manages hardware, provides a user interface, and runs as one of the first programs upon computer startup. It also touches on the kernel's role as the core of modern operating systems, acting as an intermediary between software and hardware.

05:01

🔒 Memory Management and Virtual Memory

This paragraph delves into the role of Random Access Memory (RAM) and storage in computers. It explains the distinction between primary (RAM) and secondary (hard disk) memory, emphasizing RAM's temporary nature and the persistence of data on hard disks. The paragraph further discusses how operating systems manage memory to prevent data overwrites when multitasking. It introduces the concept of virtual memory, where the OS temporarily moves data from RAM to hard disk to compensate for limited RAM space, and ensures memory protection, safeguarding it from unauthorized access by other programs or malware.

10:04

🖥️ Hardware Control and User Interaction

The final paragraph focuses on the operating system's control over various hardware devices and its evolution in user interaction. It describes how the OS, along with device drivers, allows programmers to write software that can run on different computer configurations. The paragraph also covers the transition from command-line interfaces to graphical user interfaces (GUIs), which revolutionized how users interact with computers by introducing icons and mouse control. The summary concludes by reflecting on the operating system's core components after decades of development, including its kernel, program management, memory allocation, device interaction, and user interface.

Keywords

💡Operating System (OS)

An operating system is a software that manages computer hardware, software resources, and provides services for computer programs. It acts as an intermediary between the user of a computer and the computer hardware. In the script, the OS is described as the 'brilliant piece of software' that takes over common tasks for many programs and controls the hardware of the computer.

💡Central Processing Unit (CPU)

The CPU is the primary component of a computer that performs most of the processing inside the computer. It interprets and executes instructions from the operating system and other software. The script mentions that the CPU 'is the part of the computer doing all of the calculations, processing the information, receiving input and making output'.

💡Memory Management

Memory management refers to the way in which an operating system handles the computer's RAM and ensures that data is stored and retrieved efficiently. The script explains that the OS 'keeps tight control of where and how the memory is stored' and discusses the concept of virtual memory, which compensates for the finite amount of RAM available.

💡Random Access Memory (RAM)

RAM is a form of computer memory that can be read and changed in any order, typically used to store working data. The script describes RAM as 'hardware in the computer that the CPU uses to run an application' and explains that data stored in RAM is lost when the computer is turned off.

💡Virtual Memory

Virtual memory is a memory management technique used to provide the illusion of a larger memory space than the physical RAM. The script mentions that virtual memory allows the OS to transfer data temporarily to hard disk storage and access it when needed, pretending the hard disk to be RAM.

💡Kernel

The kernel is the core part of an operating system that has direct control over everything in the system. It acts as an intermediary for requests from applications to access the hardware. The script states that 'at the heart of modern operating systems is the kernel' which is the go-between for software and hardware access.

💡Time Slicing

Time slicing is a method used by operating systems to allocate CPU time to multiple programs. The script explains that the OS can multitask by enabling time slicing, allowing it to 'run several programs at once, allocating time on the CPU between the running programs'.

💡Device Drivers

A device driver is a software that allows a computer to interact with hardware devices. The script mentions that devices come with their own piece of software called a device driver, which the OS loads to handle specific instructions for the printer or other devices.

💡Command Line Interface

A command-line interface is a text-based system used to interact with the computer, where users type commands to execute actions. The script refers to the command line interface as a way for users to interact with the operating system by typing in commands to perform tasks such as copying files.

💡Graphical User Interface (GUI)

A graphical user interface is a visual way of interacting with a computer, using icons, windows, and other visual indicators. The script describes the GUI as a development that allowed users to interact with their computer by moving objects around on the screen, instead of typing commands.

💡Batch Processing

Batch processing is a method of submitting and running jobs without human interaction, where tasks are submitted in batches. The script refers to early computers using punch cards for batch processing, where one person was in charge of making sure the cards were fed into the CPU correctly.

Highlights

Computers perform a wide range of tasks including gaming, video watching, calculations, and communication.

Operating systems integrate various hardware and software components.

Early digital computers could handle around 5,000 complex calculations per second.

Modern supercomputers perform nearly 34 trillion calculations per second.

Programs were initially written on punch cards for batch processing.

The invention of the operating system simplified tasks common to many programs.

Operating systems control computer hardware and manage resources.

An operating system runs as one of the first programs when a computer starts.

The kernel is the core of modern operating systems, acting as an intermediary for software and hardware.

The CPU, memory, and devices are the three main categories of computer hardware.

Operating systems can store and send multiple programs to the CPU for processing.

Time slicing allows operating systems to multitask by allocating CPU time to running programs.

Memory management involves the use of RAM and hard disk storage.

Virtual memory compensates for the limited RAM by using hard disk storage.

Operating systems control external devices through device drivers.

Graphical user interfaces revolutionized user interaction with computers.

Operating systems have evolved to include user-friendly features like touchscreens and virtual reality.

Despite advancements, the core components of operating systems remain consistent.

Operating systems are the hardest working piece of software on a computer.

Transcripts

(upbeat instrumental music)

- [Narrator] Computers are used for so many different tasks:

playing games, watching videos,

running calculations, communicating and collaborating.

Computers today are a mixture of different

types of hardware and software.

But there is one programme that brings them all together.

And that's the operating system.

To consider what the operating system is,

let's go back in time to the invention

of digital computers.

They could handle around 5,000 complex

calculations per second!

Impressive for the time.

But, today's super computers perform

nearly 34 trillion calculations per second.

Programmes were written on punch cards;

pieces of cardboard with holes.

These were fed, one at a time, into

the central processing unit, or CPU,

and enabled the earliest form of computer batch processing.

In some cases, one person's in charge

of making sure the cards were fed in correctly.

Their job was to correct jams

and schedule when the next programme could be run.

As computer became faster,

they were able to process punch card tasks quicker

than the cards could be fed in.

There was another problem.

Different computers' resources.

That is, the components within them,

such as RAM and the devices attached to them,

such as printers, were all different from one another.

A programmer had to write very different types

of programmes, specific to the machine

it would be running on.

Was it this card?

Or that card?

Oh, no.

It's all getting a bit complicated, isn't it?

The solution was to write a brilliant

piece of software called an Operating System, or OS.

The OS would take over the tasks common to many programmes.

Today, operating systems control

the hardware of the computer.

They manage and allocate resources,

and provide an interface for the user.

Go on then.

Turn on that computer and we'll see what happens.

An OS is one of the first programmes

that runs when a computer is turned on.

Most programmes start the same way.

The computer issues lines of code

as commands to prepare all the important elements,

like the screen and the network.

The operating system holds the collection

of all the common commands and segments them.

Rather like putting them into a library,

from which the other regular programmes can borrow codes.

(upbeat music)

At the heart of modern operating systems is the kernel.

The kernel is the go between through which

software, or applications, access the computer hardware.

This computer hardware can be split

into three main categories:

the CPU,

memory

and devices.

The CPU is the part of the computer

doing all of the calculations, processing the information,

receiving input and making output.

The operating system has the ability to store

and send multiple programmes to the CPU.

That means that once the computer finishes

one programme, it can move instantly to the next one.

Yes, that does save a lot of effort.

Allocating time for programmes and applications

to be run on the CPU is a core function

of the operating systems.

The OS can multitask by enabling time slicing.

It can run several programmes at once.

Allocating time on the CPU between the running programmes.

The next development in operating systems

was memory management.

Random Access Memory, or RAM, is hardware in the computer

that the CPU uses to run an application.

Storage is provided by a computers' hard disk.

This is where the computer keeps all its files

and where you can save your documents.

RAM is often called primary storage,

or primary memory.

Storage can be called secondary memory.

When the computer is turned off, RAM is wiped clean.

However, data on the hard disk doesn't disappear

when the computer is shut down.

Think of it like a whiteboard

to keep your workings while you're solving

a difficult problem.

Instead of combing through everything

in secondary memory to access the data required,

it can be stored temporarily in RAM.

This helps the computer get directly to it.

However, if the operating system is multitasking

and running many programmes at once,

then problems could arise.

Memory being used for one program

could get written over by another program.

Oh, dear.

To overcome this, the OS is designed to keep

tight control of where and how the memory is stored.

RAM is provided by simple circuits

that can stay in a open or closed position.

A collection of these circuits is called a chip.

Data is stored at physical addresses on the chip.

But if the CPU was running many programs,

the memory allocated to a programme may be spread

across different locations.

Often, it has to be accessed in a random order,

which is where the expression

"Random Access" originated.

Despite this, the OS presents it all as one continuous set.

But, there is still only so much space on the RAM.

Virtual memory refers to the ability of an OS

to compensate for the finite amount of RAM available.

Data is temporarily transferred

to hard disc storage and accessed when needed.

Here, the hard disc storage pretends to be RAM.

Another important feature of virtual memory

is the provision of protected memory.

Here, the OS is keeping memory secure

from being read and written over by other programmes.

For instance, viruses are malicious programmes

that could cause issues if the OS allowed them

to access the memory of other running software.

(upbeat music)

The next advantage that operating systems brought

was control over different types of hardware.

Programmers wanted to share their programmes with one another.

But they might've been written for just

a specific configuration of computer and attached devices.

For example, if your computer didn't have

a specific printer, the programme wouldn't work.

Here, the operating system took up another function;

controlling the external devices.

Devices started to come with their own

piece of software called a device driver.

When the operating system starts,

it also loads device drivers.

So now, programmers could just have

an instruction to send information to the printer

and the driver would handle the specific instructions

the printer needs to do its job.

There are drivers for all devices attached to the computer.

(upbeat music)

The final feature to look out with operating systems

is the thing we've ignored so far!

It's you!

The user.

How users interact with operating systems

is an important part of making computers user friendly.

For a long time, computer screens

were very good at displaying text.

Complex graphics needed more computing power.

So initially, computer users would interact

with the operating system via the command line interface.

If you wanted to copy a file from one place to another,

you would need to type in a command.

Knowing all of the different commands

for the command line took quite a lot of learning.

And then came the graphical user interface.

Developed by US company, Xerox.

Files and other devices connected to the system

could be represented using icons.

A mouse was an invention that allowed users

even greater control.

Users could interact with their computer

by moving objects around on the screen.

Behind the scenes,

the operating system executed the commands.

So, there you have it!

Operating systems in a nut shell.

These days, we have lots of types of operating systems,

like Mac OSX, Linux, Windows, IOS and Android.

And we have new and interesting ways of interacting

with computers, like touchscreens and virtual reality.

At their heart, computers still have the operating system,

which, after half a century of development,

still have some main components.

It has a kernel which interacts with the computer hardware.

It manages programmes using CPU.

It allocates memory that the programmes need to run.

It takes input from, and sends output to, external devices.

And it interacts with the user,

taking commands and displaying results.

It's the hardest working piece of software on your computer.

Well done, operating system.

Well done.

(romantic music)

(upbeat music)