A formal definition of a computer system could be written as:
“an electronic device which is capable of receiving information (data) in a particular form and of performing a sequence of operations in accordance with a predetermined but variable set of procedural instructions (program) to produce a result in the form of information or signals.”
Following this definition there are many different types of device that you could refer to as being a computer. These could include things such as gaming consoles, satellite navigation systems, digital radios and many more. The iGCSE course requires that you can define 4 different types of computer system. You should know the differences between them and be able to compare them to explain which type of computer system would be best used in a particular situation. The 4 types, with their advantages and disadvantages are listed below:
A Desktop PC, otherwise known as a personal computer are usually found in the home and in schools/business offices.
Personal computers are made up of input devices (e.g. keyboard), output devices (e.g. a monitor) and storage devices (e.g. a hard drive) all within, or attached to, a base unit which houses all the hardware components that make the PC work.
Personal computers can be used as either:
Standalone computer (used by one person at a time) Networked computer (part of a group of connected computers)
Standalone computers are often used by single users to perform tasks such as school work, gaming, household accounts, internet access and emailing. Networked computers are joined together on a network and are used to share resources such as printers, programs and information. They are designed to be used by multiple users who often need a username and password to access the PC. Networked computers are also used to access Intranets. These are a kind of private Internet which is only accessible to computers on the network and are used to share private information and emails etc.
|Advantages of Personal Computer||Disadvantages of Personal Computers|
|You get a better specification for your money. (better components for the same price)||Desktop PC's are large and bulky. (this makes them not very portable)|
|Cheaper to buy due to components being easier to make.||They need a constant power supply as they do not use batteries.|
|The keyboard is easier to use as it is larger than a laptop keyboard.||Need to copy files onto portable storage (memory stick) or send via email if you need to work in a different location.Note: This is because they are not portable and can't be moved easily.|
|Design of casing allows for heat to escape. This helps to keeps the PC cool.|
Laptops are portable computers and are small enough to sit on your lap.
Modern laptops are generally almost as powerful as a desktop PC and are used for similar tasks and purposes such as multimedia, school work, Internet access etc.
They have LCD screens (Liquid Crystal Display) which use low-power. This helps increase the run-time of a laptop's battery.
Like desktop PC's, laptops can be used as both standalone and networked computers.
As a standalone computer, they can be used almost anywhere due to their small size and a built-in battery which powers the laptop when there is no access to a plug socket.
Networked laptops are used for the same purposes as networked PC's……. to share resources and information.
Most laptops include a wireless network card which allows the laptop to easily connect to a wireless network when in range.
|Advantages of Laptops||Disadvantages of Laptops|
|Smaller and lighter and are much easier to transport. (portable)||Limited battery life means you need to recharge quite frequently.|
|Laptop components use low-power.||Smaller keyboards are sometimes hard to use.|
|Built-in rechargeable battery means they will work even without a mains power supply. (portable)||Laptops are prone to theft as they are often used in public places.|
|Usually come with built-in Wi-Fi which means they can access the internet and wireless networks from locations with access.||Laptops are compact and can get hotter than a desktop PC.|
|No need to transfer files onto portable storage if you need to work in a different location. You simply take the laptop with you.|
For example: Instead of using a physical keyboard they use an on-screen digital version.
Instead of using a mouse to control cursers or input commands, the user of a tablet would use their finger on the touch-screen.
Tablets usually come with 'physical buttons' which are used to switch the computer on/off and alter volume.
They are often equipped with a range of sensors including microphones and cameras.
Multimedia (movies, music, games etc) Internet access (web browsing, emailing, Skype etc) Using application software (word processing, spreadsheets etc)
Tablets use built-in Wi-Fi to allow them to connect to networks in order to share resources and Internet access etc.
Graphic designers can use stylus pens to draw directly onto the tablet's screen. This is more accurate than using a mouse to draw an image.
They can also run a wide range of custom apps that allow the tablet to perform lots of useful purposes such as:
These apps are either purchased or downloaded for free at online stores such as Google play and Apple's app store.
Most tablets also have slots for SIM cards (subscriber identity module) which is a type of memory card and allows the device to make phone calls just like on a mobile phone.
Using SIM cards can also give tablets the ability to access 3G and 4G technology. This allows the tablet to access the Internet even in areas without wireless networks.
Note: The difference between 3G and 4G is just speed...... 4G (4th generation) can download Internet data faster than 3G (3rd generation).
|Advantages of Tablets||Disadvantages of Tablets|
|Smaller and lighter (more portable).||Less storage space.|
|Touchscreen can be used with a stylus pen to draw images directly to the screen.||Not as powerful as a laptop (slower performance).|
|Built-in cameras lets users capture images and videos wherever they are.||Some people find the digital on-screen tablet keyboard harder to use compared to a larger laptop keyboard.|
|Longer battery life .||Touchscreen can be hard to use for detailed tasks such as graphics editing. (mice are easier to use for these purposes)|
Early mobile phones could only make voice calls and send text messages.
Modern smart phones (like iPhones) have much more functionality and can perform similar functions to desktop PC's and laptops. The only major difference between a tablet and a smartphone nowadays is their size
Smart phones often have the following features built-in:
The uses of smart phones are very similar to that of tablets. For example:
|Advantages of Smartphones||Disadvantages of Smartphones|
|Smallest of all computers (literally fit in your pocket).||Very small screens can be hard to see (especially if you are trying to view video).|
|Some have integrated physical keyboards (e.g. Blackberry) which many people find easier to use than tablet's on-screen keyboards.||Not as powerful as a tablet.|
|Generally cheaper than most tablets.||Lower battery life (tablets can operate longer off a single charge).|
|More practical to use for phone calls and text messaging.||Very small size makes them easier to misplace or get stolen.|