Unit 2.1

1. Unit 2.1 Lucy-Jane Constable

2. System unit components

3. Processor • A processor is an electronic circuit that can computer programs. • There are many types of processors which include the Intel Corporation's processors and the processors used in Apple computers.

4. Motherboard • This is the main circuit board in the computer. It provides expansion slots for peripherals, it holds the CPU and the memory. • They use buses to connect various components.

5. Bios • The BIOS (basic input output system) provides the processor with the information required to boot the system from a non volatile storage unit. • It provides the system with the settings and resources that are available on the system. • It includes a test that helps verify the computer to meet requirements to boot up properly. This is called the Power On Self Test (POST).

6. Power supply • A power supply unit is the component that supplies power to the other components in a computer. • There are many types of power supplies the three main ones would be, • AT Power Supply • ATX Power Supply • ATX-2 Power Supply

7. Fan and heat sink • The job of the heat sink is to keep the computer cool. • There are two types of heat sink, • Active heat sink • This utilises power and is usually a fan type. • Passive heat sinks. • These are 100% reliable, as they have no mechanical components. They are made of an aluminium-finned radiator that removes heat through convection.

8. Disk controllers • The circuits that control data transfer to and from the disk drive for example a floppy disk, hard disk or optical disc. Also from other ports such as USB and SATA. • In a PC, an IDE disk controller is typically built into the motherboard, and a cable plugs into the controller socket on one end and connects to the drive on the other.

9. Peripherals • A peripheral is a device attached to a host computer behind the chipset whose primary functionality is dependent upon the host. Various types of common peripherals would be, • CAMERA • You can use this to take photo graphs or images. You can then connect it to the computer to view them or to print them off. • PRINTER • This is an external hardware device. It is responsible for taking a hard copy of data. These are the most used peripherals. • PLOTTER • This is similar to a printer. It used pen, pencil, marker or other writing tool to make a design. These are commonly used for CAD and other print jobs. • SCANNER • This allows you to take an image or text and convert it to a digital file. You can connect this to a computer by USB, Parallel or SCSI port.

10. Expansion cards • An expansion card is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system. • A few common types of expansion cards such as network, graphic and Sam card can all be installed in a an available expansion slot.

11. Backing storage • A backing storage is a computer storage device whose capacity is larger, but whose access time is slower, than that of the computer's main storage or immediate access storage. • Flash memory • This is ideal for many applications as it has high speed, stability and low energy consumption. • Some of the applications that use flash memory are digital cameras, mobile phones and printers. • Optical media • This stores binary data in a surface that reflects the light different depending on whether a 0 or 1 is stored. • Hard disks • CD-R • These are blank but use a special read/write CD drive unit so that the user can store programs and data onto the disk. They can only be written on once. • CD-RW • Users can read, write and delete files from the disks and much as they want

12. Internal Transmission • Buses • This is a set of physical connections that can be shared by multiple hardware components meaning they can communicate with each other. • The purpose of these is to reduce the number of ‘pathways’ needed for communication between the components. • There are generally two buses within the computer, • Internal bus (front-side bus or FSB) • This allows the processor to communicate with the system’s central memory. • Expansion • This allows motherboard components to communicate with one another. (USB, Serial and Parallel Ports, PCI connectors and hard drives) • Overclocking is an increase of speed size. To run a microprocessor faster than the speed for which it has been tested and approved.

13. External Transmission • MODEM • This is a device that allows data over phone lines. • The speed depends on the phone lines and the technology used by your internet service provider.

14. Ports • USB • This is a serial bus to connect devices to the computer. • Some of the pieces of hardware that can connect mice, keyboards, PDAs and digital cameras to the computer. • PARALLEL • This is commonly used to connect printers to the computer. • SERIAL • This allows you to connect a serial device to the computer. It is capable of transmitting one bit at a time. • You can use a number of hardware components with the serial port. These include the mouse, modem. Network and printer.

15. Internal Memory • Random Access Memory (RAM) • This is used to describe the memory within the computer. • RAM requires power. When power is turned off then all the data is lost • Read-Only Memory (ROM) • This is capable of holding data and being read from. • It is capable of keeping its contents whether there is power or not