1. Computer Insides and Out Computer Basics 1.1

2. Basic Personal Computer System  A computer system consists of hardware and software components.  Hardware is the physical equipment such as the case, storage drives, keyboards, monitors, cables, speakers, and printers.  Software is the operating system and programs.  The operating system instructs the computer how to operate.  Programs or applications perform different functions.

3. Mandatory Parts of a Computer Computer Case and Motherboard CPU and RAM Drives – Hard Disk and Optical Disk Drive Interface Devices – Keyboard and Mouse Media Cards – Video and Audio Power and Cooling – Power Supply and Fan

4. Computer Case and Motherboard The first most obvious part mandatory for a computer is the case, also known as the tower. The computer case houses and protects all the delicate internal electrical components that allow the computer to function and perform complicated tasks. Within the case rests the motherboard, which acts as the nervous system of a computer. It connects all other components to each other, allowing them to work together to run programs, access memory and read the hard drive. Some motherboards will not physically fit into some computer cases, so verify the fit if building your own system.

5. CPU The CPU, or central processing unit, acts as the actual brain of the computer and is the part responsible for every computation and process the machine performs. Every action and program is controlled by the CPU, and the higher the megahertz number, listed as MHz, the faster the CPU performs processes.

6. CPU

7. What is RAM Random Access Memory (RAM) provides space for your computer to read and write data to be accessed by the CPU (central processing unit). When people refer to a computer's memory, they usually mean its RAM. If you add more RAM to your computer, you reduce the number of times your CPU must read data from your hard disk. This usually allows your computer to work considerably faster, as RAM is many times faster than a hard disk. RAM is volatile, so data stored in RAM stays there only as long as your computer is running. As soon as you turn the computer off, the data stored in RAM disappears. When you turn your computer on again, your computer's bootfirmware (called BIOS on a PC) uses instructions stored semi-permanently in ROM chips to read your operating system and related files from the disk and load them back into RAM.

8. Drives – Hard Disk and Optical Disk Drive The hard drive provides permanent storage of information and data. Personal documents, program files and your operating system all rest on the hard drive. Hard drives are available in sizes ranging from gigabytes, or GB, to terabytes, or TB. Programs and other software are typically installed via optical disk, and require a CD/DVD drive to read these disks. Various options exist for these drives, as some only read disks while others can read and write them.

9. How does a hard disk work? Hard disks is a magnetic storage device -- the magnetic medium can be easily erased and rewritten, and it will "remember" the magnetic flux patterns stored onto the medium for many years.

10. Interface Devices – Monitor, Keyboard and Mouse Having all these intricate, powerful components inside your computer case do you no good if you can't interact with the data they contain. Input and output devices, or interface devices, allow interaction with the programs and data within the computer, and the three vital components are the monitor, keyboard and mouse. The computer monitor displays the various text, graphics and data held within your computer, while the keyboard and mouse allow you to manipulate and interact with that data.

11. Media Cards – Video and Audio The video or graphics card allows the computer to communicate and display graphics on the monitor, while the sound card provides output for audio signals. In some cases, these two cards are included on the motherboard. For users serious about their visual and audio computer experience, such as gamers or those who create videos on their computers, higher quality sound and video cards are available separately.

12. Power and Cooling – Power Supply and Fan To power all these sophisticated components within your computer case, you'll need a power supply. Most cases come with a power supply pre- installed, and most power supplies also contain a built-in fan for added cooling. (Note: even unplugged a power supply has enough store power to cause harm) The components inside a computer case generate heat during operation, and this heat could cause damage if allowed to build up to an overly-high temperature. Internal fans help to dissipate this heat by venting it through the air vents cut into the case to protect your computer from overheating.

13. Ports and Cables Serial ports transmit one bit of data at a time. A telephone cable (RJ11) is used to connect a modem to a telephone outlet. USB is a standard interface for connecting hot- swappable peripheral devices to a computer. Some devices can also be powered through the USB port. FireWire is a high-speed, hot-swappable interface that can support up to 63 devices. Some devices can also be powered through the FireWire port. A parallel cable is used to connect parallel devices, such as a printer or scanner, and can transmit 8 bits of data at one time.

14. Ports and Cables (Continued) A SCSI port can transmit data at rates in excess of 320 Mbps and can support up to 15 devices. SCSI devices must be terminated at the endpoints of the SCSI chain. A network port, also known as an RJ-45 port, connects a computer to a network. The maximum length of network cable is 328 feet (100 m). A PS/2 port connects a keyboard or a mouse to a computer. The PS/2 port is a 6-pin mini-DIN female connector. An audio port connects audio devices to the computer. A video port connects a monitor cable to a computer.