103b ak 2012

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CSC103 PC Demolition Lab

An emptied PC and all of its parts

The Procedure

In the CSC103 PC Demolition Lab, pairs of students were given an old PC to take apart. The goal was to expose students to the hardware of a computer, and for the students to be able to identify the different fundamental parts. The students were asked to take note of three elements of each part found: size (relative to the entire PC), make and model number (if seen), and name. They were also asked to take pictures of each part. The pictures taken by my group (Julia Edwards and Mandy Cottle) can be found below, as well as all of the observations we made.

The PC we took apart in this lab was a Dell Windows XP Professional 1-2CPU. The model number was X10-23533.

What Parts Make Up A Computer?

What is seen when first opening a PC

When we opened up the computer, we could see many of the fundamental parts of a PC. The first thing to stand out was the processor's fan, which concealed the radiator and processor beneath. Most of the motherboard was visible, as well as the two sticks of RAM attached to it. The power supply could be seen taking up a large amount of space in the "bottom half" of the PC (the half resting on the table when we opened the computer up), and the exterior of both the hard disc drive and the CD/DVD drive were found in two slots on the "hood" of the computer. Running from part to part were various cables and bands, some of which we had to cut to remove certain parts.

While many of the fundamental parts of a PC were mentioned above, there are a few more that took some prying or closer observation to see. The following parts, and pertinent information about them, will be covered in this section:

  1. the processor (and its fan)
  2. the RAM (Random Access Memory)
  3. the CD/DVD drive
  4. the hard drive
  5. the power supply
  6. the motherboard
  7. the crystals

Each part is described in further detail below. Secondary parts (such as the battery that keeps time and the wires and cables) are described beneath the fundamental ones.

The Processor

  • 2.80 GHz
  • Intel Pentium 4
  • Found under the radiator beneath the fan
The inside of an Intel Pentium 4 processor
  • According to Wikipedia, the processor (or central processing unit) is the "brain" of the computer. It carries out all basic arithmetic, logical, and input/output operations of the system. Processors contain different components to carry out different functions (for example, one component may perform arithmetic while another sends information to be stored in memory). Two typical examples of these components include the arithmetic logic unit (ALU) - which performs the arithmetic - and the control unit (CU) - which "extracts instructions from memory and decodes and executes them"[1]. In our computers, we found a microprocessor, which "incorporates the functions of a computer's central processing unit (CPU) on a single integrated circuit (IC), or at most a few integrated circuits"[2] and is "a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system." [3]

Random Access Memory (RAM)

  • Two 256 MB chips = 512 MB of memory
Two 256MB sticks of RAM (manufactured by Micron)
  • Manufactured by Micron
  • Found sticking out of the motherboard, near the processor
  • According to Wikipedia, Random Access Memory (RAM) "is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time"[4] and "is often associated with volatile types of memory (such as DRAM memory modules), where its stored information is lost if the power is removed." [5] RAM works with the processor, storing both data and instructions to be carried out in bits of memory. There are eight bits in a byte, and 1,048,576 bytes in a megabyte[6]. Data and instructions are stored in memory in binary (meaning a series of 0's and 1's organized in a code that the processor can understand).

The CD/DVD Drive

  • This drive is able to read/write both CDs and DVDs
The CD/DVD drive in a PC
  • The technical name is the optical disc drive (ODD)
  • Found on the "hood" of the computer, next to the hard drive
  • According to Wikipedia, "In computing, an optical disc drive (ODD) is a disk drive that uses laser light or electromagnetic waves near the light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from discs, but recent drives are commonly both readers and recorders, also called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives. Optical drive is the generic name; drives are usually described as "CD" "DVD", or "Blu-Ray", followed by "drive", "writer", etc.... They are commonly used in computers to read software and consumer media distributed on disc, and to record discs for archival and data exchange purposes."

The Hard Disc Drive

  • 40 GB
The interior of a hard disc drive
An unopened hard disc drive (as it appears in a functioning PC)
  • Found next to the CD/DVD drive, in the "hood" of the computer, and above the USB ports
  • According to Wikipedia, "A hard disk drive (HDD; also hard drive, hard disk, or disk drive)is a device for storing and retrieving digital information, primarily computer data. It consists of one or more rigid (hence "hard") rapidly rotating discs (often referred to as platters), coated with magnetic material and with magnetic heads arranged to write data to the surfaces and read it from them." As opposed to RAM, the data stored on the hard disc is non-volatile, meaning that the information written on a hard drive will be stored even after the computer has been turned off.
  • When you open up the hard disc drive, one rapidly rotating disc could be seen, as well as the magnetic head and magnetic material which controls the head's movement.
  • Hard disc drives may eventually be replaced with Solid State Drives, but right now that technology is not cost-efficient enough to be implemented in all computers.

The Power Supply

  • When drawing maximum Voltage, the maximum wattage is 220W. However, if it is drawing 5V or 3.3V, the maximum wattage will not exceed 1-8W.
A power supply
  • It is large, taking up about half the space in the "bottom" half of the computer (not the "hood"). It is next to the motherboard.
  • According to Wikipedia, "A power supply unit (PSU) converts mains AC to low-voltage regulated DC power for the internal components of the computer. Modern personal computers universally use a switched-mode power supply. Some power supplies have a manual selector for input voltage, while others automatically adapt to the supply voltage. Most modern desktop personal computer power supplies conform to the ATX form factor. ATX power supplies are turned on and off by a signal from the motherboard. They also provide a signal to the motherboard to indicate when the DC power lines are correct so that the computer is able to boot up. While an ATX power supply is connected to the mains supply it provides a 5 V stand-by (5VSB) line so that the standby functions on the computer and certain peripherals are powered."

The Motherboard

  • Found under the fan for the processor, next to the power supply, and taking up a majority of space on the "bottom half" of the PC
The motherboard of a PC (with the processor and RAM removed)
  • According to Wikipedia, "a motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple computers, the logic board." The lines found on the board are the connectors that connect the different parts specified in this section to each other, so that they can communicate efficiently and work together to make the computer run (as no one part could carry out all of the computer's operations on its own!)

The Crystals

  • Also known as a crystal oscillator
The crystal found near the RAM
The crystal found near the processor
  • 2 crystals - one for the processor, and one for memory
  • Found on the logic board, near the locations of the processor and RAM
  • According to Wikipedia, "A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits designed around them became known as "crystal oscillators.""

Secondary Parts

Other "secondary parts" include:

  1. the small battery on the motherboard, used for keeping track of time
  2. the cables and belts that connected different parts together. These cables are used primarily to distribute electricity/power from the power supply among the different parts and to pass information and data.

An example of the cables which run from part to part
The battery that keeps time when the PC is turned off
An example of the belts which run from part to part