CSC231 2010 Julia
PC demolition report
For this lab, as a class we deconstructed a Dell desktop PC and removed its parts. The purpose of the lab was to familiarize ourselves with the workings of a personal computer to begin our study of microprocessors and assembly language. When studying assembly language it is very important to understand what is going on in a computer at the physical level; this is the main difference between the study of assembly language and higher-level languages. More specifically, we wanted to get an idea of what the processor and the memory of the computer look like in real life, since we will be dealing with them throughout the semester.
Parts of the Computer
The central processing unit, also known as the CPU or the processor, of a computer is the part that reads, interprets, and executes the instructions of a program. When we write in assembly language, we are sending instructions to the processor directly. The instructions must be very basic for the processor to understand them, this is why assembly programs are written in more elementary steps than programs in higher-level languages. The operating frequency of a CPU is a large factor in determining the efficiency of the computer; Modern CPUs run at operating frequencies exceeding 3 GHz. A common CPU model is the MOS 6502.
Random-access memory or RAM is a system of integrated circuits where the computer's data is stored. RAM is held on removable cards, which makes it simple to add RAM to a computer when in need of more memory. A typical desktop computer might have 2GB of RAM, but many specialized computers have more. The advantage of RAM as opposed to a hard disk is that the memory of the RAM is very quick to access, both reading and writing. Thus, a machine with more RAM will be able to do data operations more quickly.
The power supply of a computer converts 120 V AC wall power to DC power for the computer. Typical output voltages range from 3.3 to 12 V. A modern computer's power supply might supply 750 W of power to the computer to run the digital circuits as well as the disk drives and the fans.
A hard disk drive, also known as a hard disk or HCC, is where the bulk of the computer's data is stored. Data is stored magnetically on a rotating platter powered by a motor and read by a special read/write arm above the platter. Modern hard disks can exceed 1 TB, although sizes from 50-80 GB are more common. Desktop computers' hard drives are generally 3.5 inches in diameter, while laptops are 2.5 inches.
The hard drive generates the most waste heat of any part of the computer. Due to this, it is often cooled by a heat sink. A heat sink extends the surface area of materials in contact with the heat, and uses fans to disperse it. Most heat sinks are made of aluminum.
The motherboard is the central circuit board of a computer. It usually contains a connection to the power supply, a clock generator and a battery to power it, and slots for microprocessors and various "daughter boards" like sound cards or video cards. Some motherboards have various components integrated into them to avoid having to supply a separate board.
Sound and video
The computer's sound card attaches to the motherboard and manages the transmission of audio signals to and from programs using sound. Almost all computers commercially available today come with a sound card, whether it is separate or integrated into the motherboard.
A video card is an extension board which renders images to the computer's display. Many come with special features to render video better and more efficiently.
The computer we disassembled contained a floppy drive. Very few computers are manufactured with floppy drives anymore, since the medium is no longer widely used. The floppy drive reads data from floppy disks, which contain magnetic data storage.