103a-bc PC Lab
Taking Apart a Computer
Computer Parts and Their Functions
Processor: This is a unit that carries out a program; essentially, it makes the computer active. In order to accomplish this, the processor repeats a fetch-and-execute cycle that retrieves instructions from the memory and then implements the program. Transistors on the chip itself serve to exchange information to and from the component. The first processor was the Intel 4004 in 1971, a major accomplishment though it could only work 4 bits at a time. Later in 1974, the Intel 8080 was the first processor to be installed in home computers with a clock speed of 2 megahertz. Eventually Intel introduced the Pentium processor; the Pentium 4 Prescott version clocks in at 3.6 gigahertz.
Memory: Memory holds an array of bits arranged in certain patterns in different locations. These contain the information and programs (instructions to a task for the processor to follow) available in the computer. Since locations usually hold eight bits on most computers, it may be defined as a long series of bytes. When an operating system is loaded from the hard drive to the RAM, memory maintains it so that the processor can have immediate access to it. Obviously the more memory there is the more information can be stored.
CD/DVD ROM: The part that reads the information stored on CD or DVD discs. ROM is memory on which data bits have been prerecorded and therefore cannot be removed, even when the computer is off. Most CD-ROM discs can hold up to 650 megabytes. A DVD-ROM disc can hold a minimum of 4.7 gigabytes. On the surface of each disc are patterns of pits and bumps. A laser assembly inside the ROM reads the patterns in order to obtain the information on the discs and transfer it to the computer for usage.
Hard Drive: This part of the computer reads and writes data on the hard disk. The actual disks (platters) inside the drive have magnetic layers on their sides in order to hold the information they contain in different tracks. Read-write heads go over the tracks on the disks in order to actually read and write the data to them. Information in stored in strings of bytes made up of bits.
Power Supply: This component supplies energy to the computer so that it can run, transmuting AC currents into DC currents for power. It also regulates the voltage so that surges inherent in most electrical supplies do not affect the computer; this is not to say however that all computers are completely insusceptible to large changes in volt energy. Typical voltages include 3.3 volts, 5 volts, and 12 volts. Digital circuits usually utilize the 3.3 and 5 volts, while 12 volts runs the motors in disk drives and fans. In addition, the power supply also holds onto 5 volts in order to turn the computer on again when it is off.
Cables: Bits travel through the cables in order to transfer information from one part of the computer to another.
Motherboard: This is the main circuit board of the computer, where all the connectors to other boards, CPU, memory, disk drive, and controllers are located. Some devices are installed directly on the motherboard where others are connected by means of wires. Ultimately it provides a means for all the other components of the computer to communicate with each other. A bus, or universal computer switch, is a necessary part of this information exchange. Depending on what the processor is designed to use, motherboards will differ from computer to computer.
Battery: This is used so that the computer can keep track of time. It is usually attached directly to the motherboard, but may also be in a separate holder for easier replacement. It also powers the crystal in the computer itself.
Crystal: When activated by electricity, this will vibrate at a consistent frequency, thereby forming the central functioning capability of the computer. Crystals may vibrate up to 225 megahertz.
The Most Complex Machine: A Survey of Computers and Computing (pg. 13, 14, 79-80)
Lab Date: 9/22/08
Lab Partner: Christina Brown
Computer: Dell 620
- The innocent-looking box we started out with. But things quickly became much more complicated...
- What we saw upon (finally) opening our computer. After a while we found out that the green plastic handles indicated things that could just be pulled out, and that made some things a lot easier.
- For a second there it looked like we had broken it while trying to get it out of the computer, but then everything turned out fine. Phew!
- After a lot of dissection and unscrewing.
- Once again, thank goodness for the little green plastic handles.
- Here's a view of the other side.
- After using up almost all the lab time, trying to find hidden screws, and removing almost everything else, we finally managed to extract this from the box. Hooray!
- Everything we pulled out spread all over our half of the table.
- And still more stuff...
- Hey! Where'd everything go?
- There it is! Clearly we're not as good as putting computers back together again.
I'd always wanted to see what was inside of a computer, but never really had the chance to do so before this lab. Also, I had no idea of how to go about it short of using the VLH tool (Very Large Hammer). However, it turned out to be really interesting and rather fun. Thanks for this lab go to Professor Thiebaut, my great lab partner Christina, and my dad, for giving me a Leatherman for my last Christmas present.
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