Explain the difference between a serial, a parallel, and a USB port

A cable often attaches external devices to the system unit. A port is the interface, or point of attachment, to the system unit. Ports have different types of connectors, which are used to join a cable to a device. Male connectors have one or more exposed pins, while female connectors have matching holes to accept the pins.

Most computers have three types of ports: serial, parallel, and USB.

A serial port is a type of interface that connects a device to the system unit by transmitting data only one bit at a time. Serial ports usually connect devices that do not require fast data transmission rates, such as a mouse, keyboard, or modem.

A parallel port is an interface that connects devices by transferring more than one bit at a time. Many printers connect to the system unit using a parallel port.

A universal serial bus (USB) port can connect up to 127 different peripheral devices with a single connector type, greatly simplifying the process of attaching devices to a personal computer.

Describe how buses contribute to a computer's processing speed

Bits are transferred internally within the circuitry of the computer along electrical channels. Each channel, called a bus, allows various devices inside and attached to the system unit to communicate with each other.

The bus width, or size of the bus, determines the number of bits that can be transferred at one time. The larger the bus width, the fewer number of transfer steps required and the faster the transfer of data.

In most computers word size (the number of bits the CPU can process at a given time) is the same as the bus width.

Every bus also has a clock speed. The higher the bus clock speed, the faster the transmission of data, which results in applications running faster.

A computer has two basic types of buses.

A system bus connects the CPU to main memory.

An expansion bus allows the CPU to communicate with peripheral devices.

Identify components in a notebook computer

Users with mobile computing needs often have a mobile computer, such as a notebook computer and/or handheld computer. A notebook computer, also called a laptop computer, can run either using batteries or using a standard power supply. In addition to the motherboard, processor, memory, sound card, PC Card slot, and drive bay, the system unit for a notebook computer also houses other devices, such as the keyboard, pointing device, speakers, and display.

Identify components in a handheld computer 

Handheld computers run strictly on battery. Similar to desktop and notebook computers, handheld computers have a system unit that contains electronic components that process data. A handheld computer’s system unit also contains a display and may house speakers and some form of keyboard and/or pointing device. Handheld computers often have an IrDA port so you can communicate wirelessly with other computers. Many also include a serial port.