Computer Science Computer Systems and System Software

General purpose computers

are devices that have a variety of uses, the user chooses the task for the computer to complete.

Embedded systems

are more specialised, can only do limited number of things, but do them very well.

CPU

The central processing unit, is a large chip inside the computer.

RAM

Random access memory/ It is volatile. When the computer is switched off, all the data stored is lost./ It is fast to read/write.

ROM

is read-only / is non-volatile memory, which means it does not need power to keep the data inside it/It is also fast

Hard Drive

contains multiple hard disks, main storage device in your computer. / Operating System is stored here

BIOS

Basic Input and Output System/ Contains all basic code for controlling your computer hardware (keyboards, mice, monitors, hard drives)/ is in ROM

Operating System

are pieces of software that regulate interactions between software and hardware.

Roles of the OS

Error handling/Program management/Memory management/Interaction with the user/Processor management/Input and output/Security/File management

Error handling

When a program fails or encounters a problem, the operating system protects the wider system from crashing.

Program management

Often our computers are running multiple processes at once. The operating system makes sure that each application has enough resources to accomplish its tasks.

Memory management

Operating system controls where each piece of data is stored in RAM.

Interaction with the user

Operating system provides graphical user interface, makes operating computer simpler.

Processor management

Instructions are executed by the CPU, but the operating system controls which instructions are fed in to be executed.

Input and output

The operating system captures data from peripherals and provides data to the output devices to display to the user.

Security

The operating system stops unauthorized individuals from accessing data on secondary storage or the data in memory.

File management

When you save data to your hard drive, the operating system will find an available section of storage and send the data to be written to that location.