Hardware :

The hardware consists of physical components that enable programs to run. Hardware receives instructions from the software to operate. Built-in software is called firmware. Input and output devices that are not integral are called peripherals.  

Hardware can be categorized to the following:  

1. Input - provides data to the computer.
2. Processing hardware - performs given instructions from a program.
3. Storage - Where data is stored.
4. Output - Provides data to the user using the computer. 
5. Power - Supplies hardware components with the relevant amount of electricity.

Power Supply: 

Computers need DC power to function, the Power supply is provided with AC current, and convert to DC for computer components.

1. The Mother-Board: 
   This is the main/primary circuit board of the computer. This PCB connects all the functioning components. The typical motherboard has built-in components to handle graphics, sound and network connectivity. Power, memory, CPU and storage devices must be connected to the motherboard. The communication system on the motherboard is referred to the buses. 

Components on a motherboard:

            External ports: 

• PS/2 - Purple for keyboard, green for mouse
• USB - provides a simple way of communication for a large variety of devices. It can provide power and communication. USB has up to 3 versions, where the 3rd version is more powerful than the first. USB Type C is a 24-pin reversible plug connector with a smaller form factor that standardizes USB cabling further, making all USB ports the same size as the USB mini ports found on slimmer devices.
• Serial port - Also known as the RS-232 port. This is a well established standardized port that provides serial communication. used for devices that do not require high-speed communication medium. Serial port transfer bit-per-bit. Devices include diagnostic consoles, scientific instruments, point of sale systems, etc.
• Ethernet Jack - Connects the computer's networking interface to a network. The ethernet port is similar to the RJ-11(telephone jack) and accepts the 8P8C (8-pin 8-conductor) connector.
• VGA - Video Graphics Array port used for connecting the monitor to the motherboard or graphics card.  Produces analog signals.
• HMDI - High definition media interface - Used for transmitting Audio and video digital signals. Can connect monitor, projector or TV.
• LPT - 25 hole Printer port, Pink port used to connect older printers and scanners. Also known as the printer port.
• 1394 FireWire Ports -  Initially introduced by Apple. This port first had higher throughput capability than USB ports. They could also be used to connect pC's to a network without the use of a router.
• Thunderbolt - Was introduced by intel and apple to replace Firewire. T3 types. 1 and 2 use Apple's mini display port, and the 3rd version uses a Type-C USB connector. It is possible to connect up to six peripherals through different topologies on this connector.

          Internal ports:

• PCI and PCI express - Peripheral component interconnector slots allow expansion models to be fitted such as network, sound, TV tuner or cards that provide extra USB ports to the system.
• integrated drive electronics port - Connector for hard drives. The name comes from the drives having their own controller, so instead of telling the drive how to function, they transmit data.
• Serial advanced technology attachment - replaced the IDE and most common way of connecting drives today.
• SCSI ( Scuzzy) - Port for hard drives, printers, and some other peripherals. High data transfer rate.