CIS070 Fundamentalsof Computing

Theory UnitPart 2

System Components Used to Process Data

The PC system case is the metal and plastic case that houses the main system components of the computer.

Central to all of this is the motherboard or system board that mounts into the case.

The motherboard is a circuit board that contains many integral components.

A circuit board is simply a thin plate or boardthat contains electronic components.

Some of those componentsare: the CPU, memory,expansion slots, and expansion ports.

Here is a great web site formore information:

http://computer.howstuffworks.com/motherboard.htm

Electronic Components - CPU

The CPU (central processing unit) also called the microprocessor, the processor, or central processor, is the brains of the computer.The CPU is housed on a tiny silicon chip. This chip contains millions of switches and pathways that help your computer make decisions.Often people mistake the case of their computer as the CPU. The CPU is actually an internal component of the computer that cannot be seen from the outside of the system, or the inside without removing other components.A CPU is commonly the most expensive component of acomputer and is very sensitive to static electricity. Here is a great web site for more information:http://computer.howstuffworks.com/microprocessor.htm

Brands of Processors

Intel - http://www.intel.comCeleronPentium IIIPentium 4

AMD http://www.amd.comDuronAthlon chips.

Electronic Components – System Clock

The clock speed controls the speed of the processor. The system clock synchronizes the tasks in a computer, like loading data before manipulating it, etc. It is the speed at which a microprocessor executes instructions.The CPU requires a fixed number of clock ticks (or clockcycles) to execute each instruction. One clock cycle is thetime that passes from the start of one high pulse, until thestart of the next. The faster the clock, the more instructionsthe CPU can execute per second. The entire system is tied to the speed of the system clock. The system clock is a circuit that emits a continuous stream of precise high and low pulses that are all exactly the same length. Today’s computers have clock speeds of more than 1 GHz.

Electronic Components – ALU

The ALU (arithmetic-logic unit) – performs arithmetic computations and logical comparisons.

The arithmetic operations include addition, subtraction, multiplication, and division.

The logical operations involve comparisons, such as asking the computer to determine if one number is equal to, greater than, or less than another number.

By combining these operations, the ALU canexecute complex tasks.

Types of Computer Memory

Memory is also found on the motherboard.

RAM(Random Access Memory)

RAM stores information temporarily so that it’s directly and speedily available to the microprocessor.The contents of RAM are erased when the computer’s power is switched off. Sometimes called volatile.RAM is designed for fast operation. The processor acts directly on the information stored in RAM.If you "run out of memory", it means that there are too many tasks in RAM to fit any more. Sometimes these tasks use the same part of the memory and this causes a computer crash. A crash means the computer stops working. Should have at least 256 MB or RAM; however, new systems are sold with 512 MB of RAM.http://www.computermemoryupgrade.net/types-of-computer-memory-common-uses.html

ROM (Random Only Memory)

Type of memory on which instructions have been prerecorded. The instructions to start the computer have been prerecorded.

ROM allows these instructions to be read; they cannot be erased.

ROM retains information even when the power is switched off. Sometimes called nonvolatile.

http://computer.howstuffworks.com/rom.htm

Electronic Components - Ports

A port is an interface on a computer to which you can connect a device.

Personal computers have various types of ports.

Internally, there are several ports for connecting disk drives, display screens, and keyboard.

Externally, personal computers have ports for connecting modems, printers, mice, and other peripheral devices.

Serial Port

A serial port is a physical interface through which information transfers in or out one bit at a time.

Throughout most of the history of computers, data transfer through serial ports connected the computer to devices such as monitors, modems, keyboards, and other peripheral devices.

For the most part, the USB interface has replaced the serial port.

Most modern computers are connected to devices through a USB connection, and often don't even have a serial port connection.

USB to Serial Conversion Adapter

Parallel Port

Parallel ports send multiple bits at the same time over several sets of wires. Also known as a printer port or Centronics port.For the most part, the USB interface has replaced the Centronics-style parallel port.Most modern printers are connected through a USB connection, and often don't even have a parallel port connection. On many modern computers, the parallel port is omitted for cost savings, and is considered to be a legacy.

USB to Parallel Conversion Adapter

USB (Universal Serial Bus) Today just about every PC comes with Universal Serial Bus, or USB ports. In fact, many computers will even have additional USB ports located on the front of the tower, in additional to two standard USB ports at the back.

A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboard.

The introduction of USB ended many of the headaches associated with needing to use serial ports and parallel printer ports. 

You plug almost any USB device into their computer, and Windows will detect it and automatically set-up the hardware settings for the device. Once that device has been installed you can remove it from your system and the next time you plug it in, Windows will automatically detect it.

USB-A

USB-B

USB Hub

Sometimes, you may need more USB ports than you have available on your computer.To solve this problem, you can purchase a USB HUB, which is a device that allows many devices to be connected to a single USB port.

The USB Hub shown here will give you seven positions to add USB devices. This one costs approximately $40.

The one below gives you four for approximately $30.

Electronic Components Expansion Slots

An opening in a computer where a circuit board can be inserted to add new capabilities to the computer. Nearly all computers except portables contain expansion slots for adding more memory, graphics capabilities, and support for special devices.The boards inserted into the expansion slots are called expansion boards, expansion cards, add-ins, and add-ons.Here is a great web site:http://computer.howstuffworks.com/computer-memory.htm

Computer Networks

Data communications – the technology that enables computers to communicate – defined as the transmission of text, numeric, voice, or video data from one machine to another.

Four components:

Sender – computer that is sending the message.

Receiver – computer receiving the message.

Channel – media that carries/transports the message. Could be telephone wire, coaxial cable, microwave signal, or fiber optic.

Protocol – rules that govern the orderly transfer of the data sent.

Networks - A network connects one computer to other computers and to peripheral devices.

Local area network (LAN)Located relatively close location suchas in the same building or department.

Wide area network (WAN)Several local area networks within acity, state, region, territory, country,or the world.

The Internet (Interconnected

network)

The Internet is the largest network in the world.

Used every day by millions of users.

Has become an invaluable communication tool for businesses, individuals, and governments.

Email is the most common experience most people have with the Internet, allowing messages to be sent from one computer to another locally and around the world.

Networks

Intranet – networks within their own organizations. Used exclusively within an organization and contains only company information.

Extranet – applications that allowoutside organizations to accessinternal information systems. Access is controlled very tightly.