The physical components of a computer are referred to as the hardware and the code is referred to as the software. Computer hardware is made up of a number of different components, such as CPU (central processing unit), memory, and disks. An operating system enables all the different hardware components in a computer to interact with each other. There are many different operating systems such as UNIX, Linux, Microsoft Windows, etc. An operating system is a collection of programs and files which manage and instruct computer hardware.
The four main components of a computer are:
CPU is the processor which executes instructions. CPUs are traditionally measured in clock cycles e.g. 6.0 GHz.
Random access memory – RAM is an example of run-time memory. It is live when the computer is on. It loses its content as soon as we cut power. Since it is very fast, program stored in the long-term memory execute in run-time memory. Program and data being used by the computer are copied onto the RAM. This data remains the RAM as long as the program is running. When a program is done, it is removed from the RAM and this space is allocated to another program.
Hard drives are the primary long term memory of the computer. All installed programs are stored on the hard drive. All your data is also stored on your hard drive.
Computers can read from input devices such as keyboard and mouse while output to devices such as the monitor and the printer.
Memory is measured in bytes. A byte is the number of slots used by a computer to represent one character.
| 1kb | kilobyte | 1024 bytes (for simplicity, 1000kb) |
| 1mb | megabyte | 1000 kilobytes |
| 1gb | gigabyte | 1000 megabytes |
| 1tb | terabyte | 1000 gigabytes or approximately one trillion bytes |
In addition to RAM and hard drive, there is a whole array of memory devices available, each with its own strong and weak points.
Every now and then, you would like to move data from one computer to another. Floppy disks were invented with this need in mind. Due to its compact size and ease to transport, floppy disks became very popular in the 90s. Unfortunately the floppy disk technology was not upgrade. Several vendors such as iomega with their zip drives and sony with its superdisks tried to fill this gap but their technologies never became successful enough to replace the floppy disks.
Floppy disks have now become obsolete thank to CD, DVD and flash memory, and external hard drive technology. When a technology becomes very popular, it often requires several different technologies to push the technology out of the market.
Before CD-ROMs, most software was sold in floppy drives. So if you bought PowerPoint in 1994, you would buy 8 floppy disks. As the size of the software became larger and larger, floppy disks had to be replaced by CD-ROMs. ROM stands for read only memory. Unlike a floppy disk, a CD-ROM is not rewriteable. CD-RWs are rewriteable CDs. This technology is good for erasing and rewriting the archives but not suitable for editing files on the CD.
DVD-R and DVD-RW are now replacing CDs since they are capable of storing 7 to 8 times more data on the same disk. DVDs are now consumers’ choice of saving data which does not require editing such as movies and music.
We all have heard about USB. It is a revolution over older sockets. If you look at the back of your computer, you will find sockets of all shapes and sizes. Each of them with the exception of the serial port, is dedicated to a specific type of device. For example, you cannot attach a printer on a ps2 keyboard socket. USB technology has removed this restriction. It is a standard socket which accepts digital rather than an analog signal and you can plug in any device which support USB technology.
Flash memory (used in USB memory sticks) is a fast memory which can be connected to almost any computer and usually works painlessly. It is very compact and very easy to carry around. It is the technology which made floppy disks obsolete.
USB technology is very fast. This speed has finally made external hard drives possible. A typical external hard drive can now hold hundreds of megabytes of data, just like a normal hard drive. Mini HD is a technology which aims to miniaturize this technology. This new technology is expected to bring tough competition to the flash disks.
Tape drives have existed since the 1970s. The progress in this field has been steady and remarkable, yet it has gone unnoticed by the general public. A small collection of tape drives can backup terabytes of data. They were and still remain the technology of choice for industrial backups.
Internet can be used for data storage. In fact, many people use it for data storage. Services like xdrive.com have existed for years. They allow you to upload your data where it is guaranteed not to be lost since there is a team of experts watching out for viruses, doing backups, etc. In addition, you can access your data wherever you find access to the Internet. No need to worry about losing tiny flash memory sticks. With massive server space for gmail account, Google is slowly moving into the domain of data storage online.
The code on your computer is the software.
An operating system is the software responsible for the direct control and management of
The operating system interprets instructions from the user or an application and instructs the computer’s hardware. It handles the input, output, and keeps track of the data. It also enables different devices such as keyboard and CPU to communicate with each other. Examples of operating systems are UNIX, Linux, Windows XP, Windows 2000, and Mac OS.
Application software is any software that runs on top of the operating system. Microsoft Word, Adobe PhotoShop, and Oracle are some examples. Whenever you install a software on your computer which already has an operating system installed, you are installing an application software.