XP Practical PC, 3e Chapter 16 1 Looking “Under the Hood”

XP Practical PC, 3e Chapter 16 2 Looking “Under the Hood” In this Chapter, you will learn: –How a computer works –What RAM and processing circuitry looks like –How data gets into chips –What code computers use for different kinds of data –How software ties into chips, codes and circuits –How to find the technical specifications for your PC –About microprocessors

XP Practical PC, 3e Chapter 16 3 How a computer works Computers work on manipulating data. Data is all of the information that the computer uses to do tasks. Computers: –Accept data as input –Process the data –Produce output data –Store data for later use

XP Practical PC, 3e Chapter 16 4 How a computer works Data coming into a computer is called input. Input comes from the keyboard, hard drive, internet, floppy disks, mouse, etc. and is put into RAM. Computer software processes the data in RAM. Then the data is either stored or becomes output to a device such as a printer, modem, or display screen.

XP Practical PC, 3e Chapter 16 5 How a computer works A simple computer diagram

XP Practical PC, 3e Chapter 16 6 Looking at RAM and processing circuitry An integrated circuit in a computer is on a microchip nicknamed “chip.” An integrated circuit is microscopic circuitry that has been etched on a very thin slice of silicon. There are many types of chips. For instance: –Microprocessor chips do the main computer processing –RAM chips – temporarily store data and instructions –ROM chips – hold boot up instructions

XP Practical PC, 3e Chapter 16 7 Looking at RAM and processing circuitry Chips are housed in a chip carrier which is soldered or plugged into a circuit board. The main circuit board, called a motherboard, connects the chips together with electrical pathways and houses the primary function chips. RAM chips are connected to the memory module, a small circuit board and are also connected to the motherboard.

XP Practical PC, 3e Chapter 16 8 Looking at RAM and processing circuitry The inside of your computer Graphics card Memory module Microprocessor Rom Battery Slots for sound card, modem or video capture card

XP Practical PC, 3e Chapter 16 9 How data gets into chips As data comes into your computer, it is converted into a series of codes - binary digits. Binary consists of only 0s and 1s and every character can be represented by a series of these binary digits (bits). A byte (or character) is eight bits. 0s and 1s are stored like a light switch – 0 is off (or no charge) and 1 is on (or charged).

XP Practical PC, 3e Chapter How data gets into chips A Byte of data

XP Practical PC, 3e Chapter Computer code for different types of data There are many methods for coding computer data. For instance: –Text data might be stored in ASCII –Bitmap images stored using binary color code –Numbers stored in binary –Sound stored with binary codes to represent wave samples

XP Practical PC, 3e Chapter Computer code for different types of data All of the computer codes, however, share characteristics: –They are digital, a finite set of numbers –They are all binary, stored using only 0s and 1s –They re all fixed length, using the same number of bits to represent each character.

XP Practical PC, 3e Chapter Computer code for different types of data A table of ASCII codes

XP Practical PC, 3e Chapter Tying software into chips, codes and circuits All software consists of a series of instructions written in a programming language such as Visual Basic or Java. Once written, these program language instructions are converted to machine language (binary codes) so that they can be read by the computer. The conversion process is called compiling the program.

XP Practical PC, 3e Chapter Tying software into chips, codes and circuits A computer program and it’s machine language

XP Practical PC, 3e Chapter Hardware – Microprocessors A PC contains a microprocessor (or brain) that controls the types of programs it can run and how fast it can process. There are two main types of microprocessors today: –X86 processors found in PCs that run Windows (called IBM compatibles) –PowerPC processors found in Apple Macintosh computers

XP Practical PC, 3e Chapter Hardware – Microprocessors The PowerPC is a reduced instruction set computer (RISC) chip. The X86 is a complex instruction set computer (CISC) chip. The issue of which of these chips is more efficient is a matter of controversy.

XP Practical PC, 3e Chapter Hardware – Microprocessors A Pentium 4 chip beside an Athlon chip

XP Practical PC, 3e Chapter Hardware – Microprocessors Processor speed called clock speed contributes to overall system performance. Clock speed is measured in megahertz (MHz) or millions of cycles per second. The faster the clock speed, the more instructions a processor can process in a second. Some processors can process multiple instructions per clock cycle. These are referred to as superscalar.

XP Practical PC, 3e Chapter Hardware – Microprocessors Cache memory, it’s size and location is also a factor of processor speed. Level 1 cache is on the microprocessor chip. Level 2 is on a separate chip, but closer than RAM. Some processors have extended instruction sets that speed up their processing time.

XP Practical PC, 3e Chapter Hardware – Microprocessors MMX (multimedia extensions) accelerate the processing of 2-D graphics, video and sound. SSE ( streaming SIMD extensions) accelerate video, speech, image and photo processing. 3DNow! extensions speed up processing 3-D graphics.

XP Practical PC, 3e Chapter Hardware – Microprocessors Benchmark tests rate computer performance by measuring the time it takes to do standard instruction sets. There are three categories of benchmarks: –Multimedia benchmarks measure performance with multimedia data. –Integer benchmarks measure number processing. –Floating point benchmarks measure performance with floating point numbers used in special situations like CAD.

XP Practical PC, 3e Chapter Hardware – Microprocessors Results of a processor benchmark

XP Practical PC, 3e Chapter Finding the technical specifications for your PC Using Windows to view technical specifications

XP Practical PC, 3e Chapter What do you think? Who invented the first electronic digital computer? 1.Does it appear to you that the judge made the right decision, despite the fact that Atanasoff never filed for a patent? 2.Do you think that Zuse, instead of Atanasoff, should be declared the inventor of the first electronic digital computer? 3.Do you think that the computer industry would be different today if Sperry Rand had won its [patent case?

XP Practical PC, 3e Chapter Chapter Summary You should now be able to: –Understand the basic workings of your computer –Know what RAM and processing circuitry looks like –Understand binary coding of data –Understand how different types of data is coded –How software and hardware tie together –Find the technical specifications for your PC –About the basic types of Microprocessors