The document summarizes several key components of a computer system unit: 1. The hard drive stores non-volatile data magnetically on rigid disks and is read and written to by a head that moves over the disks. It is important for the disks to remain clean. 2. The audio card receives signals from the motherboard and outputs audio to speakers or headphones. It has slots to connect audio devices and facilitates audio input and output. 3. The network card allows a computer to connect to a network via an Ethernet cable and provides network connectivity, though it is not essential. 4. The fan sits over the processor and prevents overheating, which could otherwise damage the processor.

1. System unit components

2. Hard Drive Hard drive – this is a device that stores non volatile data. It has rigid layers of disks inside it; these are similar to normal disks but they store data magnetically. This data is examined by a write/read head that stays on top of the platters. It is critical for these platters to be clean and polished, as if there was even a small amount of dust on them the damage could be irreparable.

3. Audio card Audio card—this component is really similar to the graphic card, it receive information from the motherboard and sends it to other devices like speaker or headphones. It has some slots where you can plug in these devices, and it’s basically used to facilitate audio input and output

4. Network card Network card— this component allow your computer to connect to a network by simply by plugging in a network cable (Ethernet cable cat-5 cat6 etc). This is not an indispensable part of the computer but most of the computer still have it incorporated

5. Fan Fan—this component is pretty simple, it only has one job to do which quiet important as well, it basically sits on top of the processor and makes sure that the processor doesn't get over heated, in some cases if the fan is not good enough and the processor gets over heated, the processor could melt.

6. Graphic Card Graphic Card— the graphic card is a piece of hardware in the motherboard and this components sends signal to the computer screen normally through a VGA cable so that the user is able to see images from the screen. It basically represent what is stored in the memory in a form that a human can understand.

7. CPU CPU (processor) - the processor is what process the actions in the computer, it decides what task are more important and what tasks. To put it in a simple way the processor is the brain of your computer, it knows how to do tasks and when to do it. If a program is running the CPU will take the information from the Ram and any other hardware that contains information about the program and will process it by making calculations and then making decision of how to run the program.

8. Random Access Memory Random Access Memory (RAM) – RAM that is installed on computers can only function when the computer is powered. RAM is needed for your computer whenever you decide to perform an operation. Ram is a random access memory because you can access any memory cells directly if you know where you have stored the data. This is completely different from a serial access memory which has find the data stored by going through all the cells until it finds the good one.

9. ROM ROM read only memory which is a memory than can be read but not changed. This storage unit is usually used to store the bios (basic input output system) of the computer. The bios is used by the computer to run processes via input and output. It works by running to the hard drive to find the operating system then continues to run the processes.