Operating systems
There are two types of operating system: operating systems and network operating systems.
An operating system is a program. A computer is useless without an operating system. The main purpose of the operating system is to allow the application software to interact with the computer hardware.
An operating system is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer. The operating system is usually stored on the computer’s hard disk drive. Part it will also be in ROM.
Applications software-
A group of applications programs that is designed to perform specific tasks such as database management, spreadsheet, word processing, attendance, accounting, grade reporting, scheduling, and others.
It is Software that is capable of doing a specific job. When you buy application software, you need to make sure of the following:
- that it will work the hardware that you are using
- that it will work with the operating system that you are using.
Why does John brown need Software?
You cannot do anything on the computer without the software, John brown need to be able to run program
CPU (Central Processing Unit)
The CPU is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place. Intel, Celeron and Athlon are the main manufacturers of CPUs for personal computers. Intel is probably the best known because it manufactures the Pentium processor.
The processor speed
The central processing unit carries out instructions. How many instructions it can process per second is determined by the speed of the processor. This is measured in MHz or GHz. different manufactures’ processors operate in different ways, so you can only really compare the speeds of those made by the same manufacturer.
Inside the CPU
The CPU consists of three main parts:
Control unit-this controls the step-by-step running of the computer system. It sends the electronic signals, called control signals, to various parts of the system.
Arithmetic logic unit (ALU) - this does all the calculations and performs all the logical operations. For example, it can multiply two numbers together or compare two numbers to see which is the larger.
Memory-this stores all the data being processed.
Memory
Memory can be volatile or non-volatile. With volatile memory, the data is lost when the power is turned off. Non-volatile memory does not lose data when computer is switched off.
There are two types of memory:
RAM (random access memory)
- RAM is held on a computer chip
- You can write data into RAM and also read data from RAM
- RAM is volatile memory
- RAM needs power. If the power is switched off, the data in RAM disappear.
- RAM holds data and programs.
ROM (read only memory)
- ROM is held on a computer chip
- ROM cannot be altered by the user.
- You cannot store your own data on ROM
- ROM is used to hold the instruction for starting up the computer.
- ROM is non-volatile memory.
