Computer Basic Tutorials

What is a computer?
A computer is an electronic device that accepts data as input, processes data into information, stores information for future uses, and outputs the information whenever it is needed.
Computers, by a wider definition, have been around for thousands of years. One of the earliest computers was the abacus, series of beads arranged on metal rods. Beads could be slid back and forth to operate on numbers. This was a very rudimentary device and is not commonly thought of as a computer in modern times. Our idea of computers involves electricity and electronics.

Electricity makes computers more efficient. The first computers used an incredible amount of electricity, which changed voltages in vacuum tubes to operate the computer. These computers were given instructions using punch cards, and were behemoths, taking up entire floors of buildings. Only the more privileged universities and government facilities had access to them.

In the 1960s, the vacuum tube was replaced by the integrated circuit and transistor. These greatly reduced the size and power consumption of computers. They were still very large by today's standards, but more institutions had access to computing power than ever before. At the end of the decade, the microchip was invented, which reduced the size of the computer even more.
By the end of the 1970s, computers were widespread in businesses. Using a computer involved typing on a terminal (a keyboard and monitor connected to a large central computer). Soon, parts became small enough to allow many users to have a computer at their home. Thus the Personal Computer, or PC, was born.
Since then, personal computers have become tremendously more efficient. They are much smaller and yet have seen extreme performance gains. In addition to these improvements, computers have become affordable enough for many families worldwide.
Hardware is the stuff you can touch, as opposed to software which is abstract and exists only in a virtual world as computer code. Hardware is made of materials found in the universe and are subject to the laws of physics. Contrary to the latter, software is bound only by the creator's imagination and the user's willingness to use the software.
The Insides
Inside the computer case are various components that allow the computer to run.


Several CPU microchips.
The Central Processing Unit, or CPU, does nearly all the calculating. It is the main microchip in the computer that distributes tasks to all other parts of the computer. When most people talk about the processor, or chip, it is actually the CPU they are referring to.

RAM (Random Access Memory), commonly called just memory, holds computer code that needs to be operated on quickly. This allows information held in memory to quickly interact with the CPU. The amount of RAM available is limited and therefore needs to be constantly cleared and refilled (don't worry; all computers do this automatically). RAM is just one part of the computer that determines your speed.
RAM is referred to as "volatile" memory because the information stored in it disappears when the power is turned off. Hard drives and flash drives, on the other hand, contain non-volatile memory, which is like paper: it can be destroyed or erased, but when properly taken care of, can last forever.

RAM is plugged into special slots on the motherboard. There is a large link (known as a bus) from the memory to the CPU. Each motherboard has a fixed number of slots for RAM - often 2 or 4 slots. Only certain types of RAM and sizes of RAM can be used with any motherboard. So before buying, check your motherboard details.
Hard Drive

A partially dismantled hard drive, showing the disc inside.
The hard drive is the main storage area in the computer. It is usually where you put your data to be stored permanently (until you choose to erase it). It keeps data after the power is turned off. The official name for a hard disk is Hard Disk Drive (HDD), but is almost always referred to as hard drive.

Virtually all of your data is stored on your hard drive. A hard drive is composed of disk(s), where the data is recorded magnetically onto the surface, similar to records, CDs, and DVDs. The size of the hard drive (today's are usually in gigabytes) is determined by how dense (small) the recording is. Many of today's major programs (such as games and media creating and editing programs like Photoshop) and files (such as pictures, music, or video) use a considerable amount of space. Most low-end computers, as of 2011, are shipped with a 160GB (gigabyte) or larger hard drive. Currently, in 2017, it is common to find desktop computers and laptops with 1000GB (1 Terabyte) hard drive or more. As an example, an average .mp3 file takes between 7.5 and 15MB (megabytes) of space. A megabyte is 1/1024th of a gigabyte, thus allowing most new computers to store thousands of such files.

Users who wish to store a lot of media on a computer will want a larger hard drive. As will users who want to store numerous large programs, like modern games, or videos, which both require a lot of space. A full size film is over 4 gigabytes. Video games today are commonly downloaded but used to be distributed via DVD discs that store data, called DVD-ROM (read only memory, which can be read off the disk, but not modified). A DVD can be anywhere from 4.7GB for a single layer disk to 8.5GB for a double layered disk... and many large programs are already taking up more than one disk.
Another concern for users who want higher performance is hard drive speed, measured in RPM (rotations per minute). Most desktop hard drives today are 7200RPM models. Lower end 4200RPM models are not commonly seen in new systems (other than laptops).