1. INTERNAL SYSTEM UNIT COMPONENTS Olivia Johnson
2. PROCESSORS The CPU (central processing unit) is the ‘brain’ of the computer. It carries out instructions of computer programs, which is how they start up. It also problem solves and performs basic logical and arithmetic operations. Some processor chips can contain more than one CPU. These are called multi-core processors. The processor produces a lot of heat, so a fan and heat sink has to be attached. Companies are developing lower voltage processors, so that less heat is produced.
3. MOTHERBOARD This is the main circuit board for the computer. It brings all of the different components together, and contains ports that you can add peripherals to. It is called the motherboard because it is the main board, and other circuit boards connect to it.
4. BIOS BIOS stands for Basic Input/output System. This checks what components are attached to the computer and whether they are working. It also loads up the operating system. The BIOS is a type of ROM, and it is stored on its own chip. You cannot remove the BIOS, it is read only. The BIOS generally doesn’t have a user interface, it is just codes.
5. POWER SUPPLY The power supply unit (PSU) converts mains alternative current into low voltage direct current, of either 12V or 5V. PSUs have short circuit protection, as well as over voltage and under voltage protection, to protect the components from power surges.
6. FAN AND HEAT SINK A heat sink transfers heat from the processor into the surrounding air. It has ridges in it to maximise its surface area, in order to cool more. Most heat sinks are made of aluminium. Fans usually sit on top of heat sinks, and circulate the air, allowing it to cool more effectively. A heat sink without a fan is called a passive heat sink, and one with a fan is called an active heat sink.
7. HARD DRIVE A hard drive (HDD) is a metal disk coated with magnetic material that spins rapidly, with a magnetic head moving over it to read and write data. This is known as secondary storage, and it is where the user’s files are kept. There can be master/slave hard drives in a computer. These are two different HDDs but one is in charge of the other, deciding where data is kept.
8. PORTS Ports are where you can add external components to a computer, such as USBs. You have up to 127 devices connected via USB. Ports can be for either input or output, for example, a keyboard would be input and a monitor would be output. There are other connections, such as parallel and serial ports. A parallel port was used for printers and similar peripherals, and serial ports are connections that only transfer one bit at a time.
9. INTERNAL MEMORY ROM stands for Read Only Memory. This contains things like the BIOS, and other things that the computer needs to run. ROM holds its memory even when the computer is switched off. RAM stands for Random Access Memory. This is volatile memory. When the computer is switched off, it loses the data. RAM holds data so that it doesn’t have to be loaded off the HDD all of the time, which means it doesn’t take as long to open programs. Cache is similar to RAM, but it is even faster. This stores data transparently.
10. SPECIALIZED CARDS Graphics/video cards generate the output of images to a computer screen. Specialized cards are smaller circuits than the motherboard, but they contain their own processor, BIOS and RAM. Network cards allow connection to a modem or wireless connection.