User:Ihm08/CSC231 Demolition Lab

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PC Demolition Lab
Ihm08-cs231-wholecomputer.jpg

Assorted Information
Me: Ian McEwen
Class: CSC231
Date: September 14, 2010
Brief Description
In the lab, we dismantled a computer – in this case, a dead Dell desktop PC (pictured above after the first step of dismantling). The goal in doing this was to understand the "main players" in a modern computer – primarily, for the sake of this course, the processor, memory, and their interaction by way of the motherboard.


In Summary

What we pulled out:

  • CPU
  • RAM (memory)
  • Motherboard
  • HDD
  • PSU
  • Assorted I/O devices (optical, floppy, zip)
  • Assorted daughterboards (video, sound, network)
  • Assorted cables
  • Assorted heatsinks and fans

In Greater Detail

CPU

Ihm08-cs231-cpu-top.jpg Ihm08-cs231-cpu-bottom.jpg

The CPU (Central Processing Unit) is the specific chunk of electronics dedicated to executing low-level instructions given various numerical inputs. It coordinates with the RAM to create a physical approximation of a Turing machine with finite memory, acting approximately as the head which reads and moves from place to place on the tape. This CPU is an Intel brand Pentium-style (x86) processor. I'm not sure which sort it is exactly, but in a modern computer you might find an Intel Core brand processor of perhaps 2-3GHz, and rated to dissipate (at maximum) perhaps 100W of heat.

RAM (memory)

Ihm08-cs231-RAM.jpg

The RAM (Random-access Memory) is a form of data storage which is used for those things which require quick access speed and close integration with the CPU but which do not require persistence in the absence of electrical current. The RAM acts, in a certain sense, as the "tape" of the abstract Turing machine which a physical computer approximates. A typical modern computer might include one to four gigabytes of RAM.

Motherboard

Ihm08-cs231-motherboard.jpg

The motherboard is the conceptual core of a modern computer, connecting the disparate elements together and providing some functionality such as the so-called 'northbridge', which negotiates interactions between the CPU, RAM, sometimes video cards, and the southbridge, another element of the motherboard, which negotiates interactions between other components. The motherboard (along with the daughterboards) also provides most of the connections to the 'outside world' (in the form of connectors such as USB or Ethernet).

HDD

Ihm08-cs231-HDD.jpg Ihm08-cs231-HDD-bent-pins.jpg

The HDD (Hard Disk Drive) is another form of data storage, differentiated from the RAM primarily by quantity of data storage (the HDD is typically much larger) and persistence (an HDD retains the values stored in it even in the absence of electrical current). It interacts with the CPU and RAM as an I/O (input/output) device. A modern individual hard drive generally stores amounts of data in the tens or hundreds of gigabytes.

PSU

Ihm08-cs231-wholecomputer.jpg

(The PSU can be seen to the right of the image, near the viewer).

The PSU (Power Supply Unit) is responsible for converting AC power from the wall (110V) into DC power of the proper voltages for components inside the computer (5V and 12V); most consumer PSUs also include the relevant cables for providing this power to components. A typical modern PSU might generate 300-500W of power.

Assorted I/O devices (optical, floppy, zip)

CSC231 rb CD Drive.jpeg Ihm08-cs231-floppy.jpg Ihm08-cs231-zip.jpg

These various parts have in common that they read external media of various sorts (optical disks such as CDs, magnetic media such as floppies, or such) and provide this data to the rest of the computer to use. They, like the HDD, are input/output devices, in a sense external to the core functionality of the computer.

Assorted daughterboards (video, sound, network)

Ihm08-cs231-video-card.jpg Ihm08-cs231-sound-card.jpg CSC231 rb Network Card.jpeg

These various parts have in common that they extend the functionality of the motherboard, connecting through sockets known by names such as AGP and PCI. The three pictured here provide (respectively) video output, sound input and output, and networking (via Ethernet). These are called 'daughterboards' in the extended terminological metaphor of the designers of the modern computer.

Assorted cables

Ihm08-cs231-wholecomputer.jpg

These are bits of metal which connect one thing to another so that the various logic circuits can do their thing. They're all over the picture above, both the multi-colored power cables near the front and center and the grey ribbon-style cables near the back.

Assorted heatsinks and fans

Ihm08-cs231-wholecomputer.jpg Ihm08-cs231-cpu-heatsink.jpg

These help to cool the system, as heat is created as a consequence of operation. Heatsinks (such as the one to the right) disperse heat away from whatever they attempt to cool, while fans (such as the one hidden inside the green thing in the image to the left) move air around so as to disperse heat from heatsinks or directly from elements, as well as move this heat away from the entire computer.

Further Reading

Wikipedia is recommended; an acceptable starting place is wikipedia:Personal computer hardware