A typical desktop is an example of computer system unit which consist of keyboard, a mouse and a monitor. It is an enclosure of all the main interior components of a computer which is also known as computer case, computer chassis or computer tower. Cases are basically made up of steel and aluminium but plastic can also be used.

Functions of Computer System Unit

Primary function is to hold other components together and protect the sensitive parts from outside elements. A computer case is also large enough to allow upgrades by adding another hard driver. It is easy to open a system unit to replace parts and install upgrades. In most computer system units front side contains elements that are frequently used by user of that unit like power button, disk drive, audio outlet headphones, and number of USB connections. Whereas the back side contains all the connection for power, monitor, keyboard , mouse , internet connection and other peripheral devices.

Components of Computer System Units

• Desktop or laptop: Laptops are preferable to user who prefer portability, this unit is common for someone like a college student, consumers who travel frequently and business people. Desktop is intended to the user who does not need computer which is portable, having large design and often have more features and computing power. User will use the one which is best suited for their situation.
• Motherboard: This is the very first component installed in the in the system unit, which hold all the circuitry that ties the functions of the computer components together. Engine of the car is the example of motherboard without the engine car will not take you very far! After add the engine you have got the start working vehicle like a motherboard to system.
• Central processing unit: CPU is like a power box included with your system units. CPU is like a brain of the computer which sits on the motherboard and does actually have its own fan. Fan is required these days because processors are so fast they need to be cooled down. All the instruction you give the computer like mouse click it go through the CPU which process billions of cycle per second. There are six-core and eight-core processors are also available and the more advanced technology higher the cost.
• Memory, Cache, RAM, ROM: Cache sits next to the CPU which is a temporary memory. RAM chip is also same which is known as random access memory is volatile or temporary. Whenever a new program is turn on its instruction is stored in Ram while the machine is on. Once the machine is shut down both the cache and Ram is clean off. RAM storage is common at twelve gigabytes. Rom is permanent and non-volatile memory. When you turn on your computer the start-up instruction that are stored on ROM begin to execute and when you turn off the instruction still remain on ROM. Another storage device hard drive is attached to the motherboard but it is connected to the circuitry by electrical wire. Hard drive stores software you have put in your system like music player, Firefox, notepad++. Storage of hard drive commonly begin with one terabytes and goes up to two and half.
• Network Connections: A part of system unit is wireless local are network card or LAN card, It connects to our wireless Internet. Another way to connect to Internet is hardware but it is slightly larger than wireless or in another way is plugging a jack into the network interface card (NIC).