Introduction To Computers: Hardware and Software In this section of notes you will learn how the basic parts of a computer work as well what are the fundamental categories of computer programs

What Is Hardware? The physical components of a computer system e.g., a monitor, keyboard, mouse and the computer itself.

Basic Units Of Measurement Bit binary digit smallest unit of measurement two possible values Byte 8 bits Show on the board how the number of bits translates to the amount of information that can be represented (number of possible combinations) Word The number of adjacent bits that can be stored and manipulated as a unit 32, 64 for home computers, 128 for the most powerful

Large Units Of Measurement (Memory, Storage) Note: use powers of two because computer memory and storage are based on the basic unit (bit). Kilobyte (kB) – a thousand bytes (1,024 = 210) Megabyte (MB) - a million (1,048,576 = 220) Gigabyte (GB) – a billion (1,073,741,824 = 230) ~ A complete set of encyclopedias requires about 600 MB of storage Terabyte (TB) – a trillion (1,099,511,627,776 = 240) ~ 20 million four-drawer filing cabinets full of text

Small Units Of Measurement (Speed) millisecond (ms) – a thousandth of a second (1/1,000 = 10-3) microsecond (μs) - a millionth of a second (1/1,000,000 = 10-6) nanosecond (ns) – a billionth of a second (1/1,000,000,000 = 10-9) Millisecond – hard drive seek time speeds (track-track) Nanosecond – speed of RAM

High Level View Of A Computer

Input

Input Devices Used by a person to communicate to a computer. Person to computer

Example Input Devices Keyboard Mouse Need not be mundane! (A Jouse) From http://www.jouse.com/

Processor

Processor The brains of a computer (maybe not…) A real processor

Processor Speed Determined by: Type of processor e.g., Pentium III, IV, AMD Duron, Athalon Clock speed 1 Hz = 1 pulse is sent out each second (1 second passes between each pulse) 10 Hz = 10 pulses are sent out each second (0.1 seconds passes between each pulse) : 25 MHz machine = 25 million pulses sent out each second (0.000 000 04 seconds between each pulse or 40 ns between pulses)

The Processor And The Computer Control Unit Directs the flow of data traveling between the different parts of the computer ALU - If the control unit encounters information that requires mathematical calculations or a logical operation to be performed then it is sent to the ALU. Image from Peter Norton's Computing Fundamentals (3rd Edition) by Norton P.

Memory

RAM Volatile Used for temporary storage Typical ranges 256 MB ~1 GB

RAM (2) Means direct access to any part of memory Picture from Computers in your future by Pfaffenberger B

How Does RAM Work? Like a leaky bucket From www.howstuffworks.com

How Does RAM Work? Like a leaky bucket Transistor Capacitor From www.howstuffworks.com

RAM: A Collection Of Capacitors A capacitor

Types Of RAM Old versions of RAM EDO RAM SD-RAM Slowest For older computers SD-RAM Faster Was the former standard EDO RAM Name means it allows another access to memory to start while the previous access is still being completed 60 ns Pentium I 4MB – 64 MB chips SD-RAM Synchronous RAM (runs at processor speed) 7 – 8 ns Pentium I onwards 32 – 512 MB chips P100 & P133 MHz – speed information is sent Pictures from http://www.geekshelter.com

Types Of RAM (2) Newer version of RAM DDR-RAM (Double Data Rate RAM) Double the speed of SD-RAM Originally exclusively used with AMD processors RD-RAM (Rambus Dynamic RAM) Produced by Rambus Fast! Used with Pentium 4 powered computers DDR-RAM Like SD-RAM but able to send data twice as fast PC-200MHZ (The PC-1600) and PC-266MHZ (The PC-2100). Now up to 333 MHz. Originally used only with AMD Athalon and Thunderbird (but no longer) 128 MB – 1 GB chips Less than 1 ns RD-RAM 128 MB – 1 GB 400 or 800 MHz Pictures from http://www.geekshelter.com

Storage

Storage Vs. Memory? Memory (e.g., RAM) keep the information for a shorter period of time (usually volatile) faster more expensive Storage (e.g., Hard disk) the information is retained longer (non-volatile) slower cheaper

Categories Of Storage 1) Magnetic 2) Optical Floppy disks Zip disks Jazz drives Hard drives 2) Optical CD-ROM DVD

Magnetic Drives: A Hard Drive In Action

Magnetic Drives: Storage Capacities Floppy disks ~ 1 MB Zip disks 100 or 250 MB Jazz drives 1 – 2 GB Hard drives ~20 – 120+ GB

Optical Drives: Reading Information Pits and land don't represent info. Land represents 0's Transition (pits-land, land-pits) represents a 1.

Optical Drives: Recording and Reading Information

Optical Drives: Re-writing

Optical Drives: Re-writing

Optical Drives CD's DVD-ROM ~ 700 MB storage CD-ROM (read only) CD-R: needs a CD-burner to create (record) to a CD CD-RW: can write and erase CD to reuse it (re-writable) DVD-ROM ~ 3.8 – 17 GB storage DVD- ROM (read only) Many recordable formats (e.g., DVD/CD-RW, DVD-RAM, DVD-R, CD-RW etc)

Output

Output Devices Displays information from the computer to the a person.

The Most Common Output Device: The Monitor Types of computer monitors CRT's (Cathode Ray Tube) LCD's (Liquid Crystal Display)

CRT's Monitors Images are displayed with dots (pixels) drawn with light "guns" Picture from Computer Confluence by Beekman G.

LCD Monitors Employ a conductive grid for each row and column The meeting of a row and column allows light to be emitted (a pixel can be seen)

Colour LCD Monitors Use three subpixels: One wire for each row One wire for each subpixel One colour filter for each colour (red, blue, green)

Some Determinants Of The Quality Of Monitors Size Resolution Color depth Dot pitch

1) Monitor Quality (size) Measured diagonally

2) Monitor quality (resolution) Columns of pixels x Rows of pixels For a given monitor size, the higher the resolution the sharper the image Col 1, Row 1 Col 2, Row 1 Col 3, Row 1 … Col [c], Row 1 Col 1, Row 2 Col [c], Row 2 Col 1, Row 3 Col [c], Row 3 : Col 1, Row [r] Col 2, Row [r] Col 3, Row [r] Col[c], Row[r]

3) Monitor Quality (Color Depth) The number of possible colors that can be displayed for each pixel. e.g. monochrome (single color) 1 2 possible values Uses up 1 bit of space

3) Monitor Quality (Effects Of Color Depth) 2 colours 16 colours 256 colours 16 million colours

4) Monitor Quality (Dot Pitch) Dot pitch is the distance between the center of each color dot (mm) dot pitch

Refresh rate of monitors How fast the screen is redrawn (70 Hz / 70 times per second is usually a good minimum)

All The Basic Parts Together Diagram from http://www.jegsworks.com

The Motherboard ISA/PCI – for older/newer way of hooking up things like sound cards, internal modems etc Connectors – hard and floppy drives, CD-ROM Memory – SIMM (old - smaller) and DIMM (newer – larger) Diagram from http://www.jegsworks.com

Printers Common types Inkjet Laser Note: By default on the CPSC network you only have access to text-only printers (do not print formatted text or graphics on them!) You can pay a minimal fee to access the laser printers.

How Inkjet Printers Work. Use a series of nozzles to spray drops of ink directly on the paper Print heads Slots for print cartridges Ink nozzles Picture from www.howstuffworks.com

How Laser Printers Work Use a laser to produce patterns on an ink drum using static electricity The drum is made out of photoreceptive material (ability to conduct electricity affected by the exposure to light – photocopiers work this way) The drum is give a positive electrical charge by the Corona wire Then as the drum rotates a laser is shined across different parts of the surface of the drum This discharges the electrical charge and ‘draws’ characters and images onto the drum (the discharged areas) The drum is then covered with toner (fine black ink) which sticks only to the discharged areas (Kind of like putting ink on parts of pop can and rolling it in flour) The drum is then rolled over a piece of paper and corona wires under the paper employ another electrical charge to pull the toner off of the drum onto the paper. The fuser heats the paper to melt the toner powder and fuse the toner to the paper (that’s why the paper comes out warm) The discharge lamp removes the electrical charge from the printer drum Diagram from www.howstuffworks.com

Software The instructions that tell the hardware what to do. Balance my check book. Do taxes Print out my resume : :

Categories Of Software Application programs (applications) Operating systems Compilers

1) Common Types Of Application Programs Word processors Spreadsheets Databases Presentation software Web browsers : :

2) Operating Systems: What Do They Do? Act an an intermediary between the user and the hardware Manage the resources of the computer Some may act to secure some parts of the computer

Operating Systems: The Intermediary Between The User And The Hardware

Operating Systems: Manage System Resources (1) e.g., Processor time A = B + C

Operating Systems: Manage System Resources (2) e.g., Memory management RAM A = B + C

Operating Systems: Securing The Computer (not done) Single (faceless) user – security less of an issue Claude Rains from Phantom of the Opera My resume

Operating Systems: Securing The Computer (done) Multiple users – security is more important Bill Mary George Mary's assignment Bill's assignment George's assignment

3) Compilers (Real-World) Real life translation Same to you buddy! Merry Christmas and Happy New Year! Huh?

3) Compilers (Computers) Anybody who has this executable on their computer can then run (use) it. 1) A programmer writes a computer program 3) An executable program is created 2) The compiler translates the program into a form that the computer can understand

Summary What is hardware? What are the basic parts of a computer? What are some common input devices? What is the purpose of the processor? What are some examples of modern processors and their speeds? How does computer memory work? What are some common types of computer storage devices? What are the main types of computer monitors and how do they work? What are some of the factors that determine the quality of computer monitors? What is software? What are the main categories of software What are application programs? What do operating systems do? What is a compiler?