Cross Section of CD-R

• .

Polycarbonate Substrate

Printed labelProtective lacquerReflective gold layer

1.2mm

Dye layer

Transmit beam

Reflective beam

Dark spot burned by laser

Information on the CD disks

• Data are written in series form and are read in series fashion, too.

• The disks have to rotate with a constant linear velocity for CD-music.

• Single-speed CD-ROM drives operate at 75sectors/sec---153,600 bytes/sec in mode 1 and 175,200 bytes/sec in mode 2.

• The difference between 1 and 2 is between music and video mode or data mode.

Yellow Book Definition

• The basic format of a CD-ROM consists of encoding every byte in a 14 –bit symbol.

• A group of 42 consecutive symbols forms a 588-bit frame. (each frame holds 192 data bits and the remaining 396 bits are used for error correction and control)

• 98 frames make 1 sector

Logical data layout on a CD-ROM

• The physical layout

Data

Preamble

Bytes 16 2048 288

ECC

14 bits make one symbol42 symbols make one frame98 frames make one sector

The Reliability of CD-ROM

• They are highly reliable.

• One undetected error is less than 1 in 10 .

• What this number mean?

• If we stack the CD-ROM disks up to 1 billion miles high, we may have one undetected error!!

25

1 billion miles high!!!

                                     

We already know that the average distance between the center of the Moon and the center of the Earth is about 385,000 kilometers (239,000 miles).

1 billion/23900 = 4184---more than 4,000 piles of disks to the Moon!

The price paid for the reliability?

• With the ECC added into the data on CD-ROM format, we only have 28% of efficiency of disk space usage.

File Names on CD-ROM

• By international standard, there are 3 levels.• Level 1--- file names up to 8 characters,

followed by an extension of up to 3 char. Only upper letters, digits and _ is allowed.

• Directory names may not including extensions and directory names can nested up to 8 deep.

• Level 1 also requires that all files to be continuous.

One important property for level 1 is the compatibility.

• Any CD-ROM conform this standard (IS9660) can be read using MS-DOS, an Apple computer, a UNIX computer, or just about any computer.

Level 2 and Level 3

• Level 2 in this IS9660 standard allows 32 characters.

• Level 3 allows noncontiguous files.

• We pay the price for the compatibility.

Similarity to HD

• Both are external memories

• Both disks rotate and have the head move above the disks

• The heads float on the surface of the disks

• Both can be made with high capacity

The Differences Between the Two

• HD is much faster than CD-ROM or CD-RW

• CD-ROMs have much longer life if handled carefully.

DVD

• The capacity improvement are due to 3 factors:

• 1. Smaller pits (0.4 microns versus 0.8 )

• 2. A tighter spiral (0.74 microns versus 1.6)

• 3. A red laser at 0.65 microns versus 0.78 microns.

Capacity of DVD

• 1. Single-sided, single-layer (4.7GB).

• 2. Single-sided, dual-layer (8.5GB).

• 3. Double-sided, single-layer (9.4GB).

• 4. Double-sided, dual-layer (17GB).

Keyboard

The part of the computer that we come into most contact with is probably the piece

that we think about the least. But the keyboard is an amazing piece of

technology. For instance, did you know that the keyboard on a typical computer

system is actually a computer itself?

Keyboard

• At its essence, a keyboard is a series of switches connected to a microprocessor that monitors the state of each switch and initiates a specific response to a change in that state. .

Keyboard Types

• The most common keyboards are:

• 101-key Enhanced keyboard

• 104-key Windows keyboard

• 82-key Apple standard keyboard

• 108-key Apple Extended keyboard

Inside the KeyboardThe processor in a keyboard has to understand several things that are important to the utility of the keyboard, such as:

•Position of the key in the key matrix. •The amount of bounce and how to filter it. •The speed at which to transmit the typematics.

                                              

 

A look at the key matrix.

The bottom view of a mouse

Mouse Inside View

Another view of a mouse from inside

The Optical MouseWith advances it mouse technology, it appears that the venerable wheeled mouse is in danger of extinction. The now-preferred device for pointing and clicking is the optical mouse.

Developed by Agilent Technologies and introduced to the world in late 1999, the optical mouse actually uses a tiny camera to take 1,500 pictures every second. Able to work on almost any surface, the mouse has a small, red light-emitting diode (LED) that bounces light off that surface onto a complimentary metal-oxide semiconductor (CMOS) sensor. The CMOS sensor sends each image to a digital signal processor (DSP) for analysis. The DSP, operating at 18 MIPS (million instructions per second), is able to detect patterns in the images and see how those patterns have moved since the previous image. Based on the change

Developed by Agilent Technologies and introduced to the world in late 1999, the optical mouse actually uses a tiny camera to take 1,500 pictures every second. Able to work on almost any surface, the mouse has a small, red light-emitting diode (LED) that bounces light off that surface onto a complimentary metal-oxide semiconductor (CMOS) sensor. The CMOS sensor sends each image to a digital signal processor (DSP) for analysis. The DSP, operating at 18 MIPS (million instructions per second), is able to detect patterns in the images and see how those patterns have moved since the previous image.

Optical mice have several benefits over wheeled mice:

•No moving parts means less wear and a lower chance of failure. •There's no way for dirt to get inside the mouse and interfere with the tracking sensors. •Increased tracking resolution means smoother response. •They don't require a special surface, such as a mouse pad.

How Monitor Works ?

1. CRT monitor—the only vacuum tube left in the computers.

Display TechnologyDisplays have come a long way since the blinking green monitors in text-based computer systems of the 1970s. Just look at the advances made by IBM over the course of a decade:

•In 1981, IBM introduced the Color Graphics Adapter (CGA), which was capable of rendering four colors, and had a maximum resolution of 320 pixels horizontally by 200 pixels vertically.

•IBM introduced the Enhanced Graphics Adapter (EGA) display in 1984. EGA allowed up to 16 different colors and increased the resolution to 640x350 pixels, improving the appearance of the display and making it easier to read text.

•In 1987, IBM introduced the Video Graphics Array (VGA) display system. Most computers today support the VGA standard and many VGA monitors are still in use.

•IBM introduced the Extended Graphics Array (XGA) display in 1990, offering 800x600 pixel resolution in true color (16.8 million colors) and 1,024x768 resolution in 65,536 colors.

Most displays sold today support the Ultra Extended Graphics

Array (UXGA) standard. UXGA can support a palette of up to 16.8 million colors and resolutions of up to 1600x1200 pixels, depending on the video memory of the graphics card in your computer.

The maximum resolution normally depends on the number of colors displayed. For example, your card might require that you choose between 16.8 million colors at 800x600, or 65,536 colors at 1600x1200.

1: Red out 6: Red return 11: Monitor ID 0 in

2: Green out 7: Green return

12: Monitor ID 1 inor data from display

3: Blue out 8: Blue return 13: Horizontal Sync out

5: Ground 10: Sync return

15: Monitor ID 3 inor data clock

Multi-scanning MonitorsIf you have been around computers for more than a decade, then you probably remember when

NEC announced the MultiSync monitor. Up to that point, most monitors only understood one frequency, which

meant that the monitor operated at a single fixed resolution and refresh rate. You had to match your monitor with a

graphics adapter that provided that exact signal or it wouldn't work.

The introduction of NEC MultiSync technology started a trend towards multi-scanning monitors. This technology allows a monitor to understand any frequency sent to it

within a certain bandwidth. The benefit of a multi-scanning monitor is that you can change resolutions and refresh

rates without having to purchase and install a new graphics adapter or monitor each time. Because of the obvious

advantage of this approach, nearly every monitor you buy today is a multi-scanning monitor.

Dot Pitch

• Briefly, the dot pitch is the measure of how much space there is between a display's pixels. When considering dot pitch, remember that smaller is better. Packing the pixels closer together is fundamental to achieving higher resolutions.

A display normally can support resolutions that match the physical dot (pixel) size as well as several lesser resolutions. For example, a display with a physical grid of 1280 rows by 1024 columns can obviously support a maximum resolution of 1280x1024 pixels. It usually also supports lower resolutions such as 1024x768, 800x600, and 640x480.

Color DepthThe combination of the display modes supported by your graphics adapter and the color capability of your monitor determine how many colors can be displayed. For example, a display that can operate in SuperVGA (SVGA) mode can display up to 16,777,216 (usually rounded to 16.8 million) colors because it can process a 24-bit-long description of a pixel. The number of bits used to describe a pixel is known as its bit depth.

With a 24-bit bit depth, 8 bits are dedicated to each of the three additive primary colors -- red, green and blue. This bit depth is also called true color because it can produce the 10,000,000 colors discernible to the human eye, while a 16-bit display is only capable of producing 65,536 colors. Displays jumped from 16-bit color to 24-bit color because working in 8-bit increments makes things a whole lot easier for developers and programmers.

Bit-Depth Number of Colors1 2 monochrome2 4 CGA4 16 EGA8 256 VGA

16 65,536 (High Color, XGA)24 16,777,216Truecolor,SVGA32 16,777,216

(True Color + Alpha Channel)

You will notice that the last entry in the chart is for 32 bits. This is a special graphics mode used by digital video, animation and video games to achieve certain effects.

Flat Panel Display --- LCD

• A simple calculator display.

Color LCD

• R-G-B

The States of Matter

• 1. Solid

• 2. Liquid

• 3. Gas

• 4. Plasma

• Liquid Crystal

• What is a Plasma?• Plasma is one of four states of matter.

Plasma, the least familiar state of matter to us here on Earth, is actually the most common form of matter in the universe. Plasma makes up 99% of all visible matter in our universe. Although naturally occurring plasma is rare on Earth, there are many man-made examples. Inventors have used plasma to conduct electricity in neon signs and fluorescent bulbs. Scientists have constructed special chambers to experiment with plasma in laboratories.

Properties of Liquid Crystal

• There many different types of liquid crystals.• The type we use in LCD is called nematic

liquid crystals. The display using this type of liquid crystal is called TN display.

• http://www.howstuffworks.com/lcd2.htm

A Simple Monochrome LCD • A-Mirror

• B-A piece of glass with film

• C-A glass with transparent conductive coating

• D-Liquid crystal

• E- A glass partially coated conductive film.

• F-Another piece of glass with polarizing film.

Passive Matrix versus Active Matrix

• http://www.howstuffworks.com/lcd4.htm

• LCD technology is constantly evolving. LCDs today employ several variations of liquid crystal technology, including super twisted nematics (STN), dual scan twisted nematics (DSTN), ferroelectric liquid crystal (FLC) and surface stabilized ferroelectric liquid crystal (SSFLC).

Active Matrix Display

• For the display with 1,024 columns by 768 rows by 3 subpixels, we get 2,359,296 transistors etched onto the glass! If there is a problem with any of these transistors, it creates a "bad pixel" on the display. Most active matrix displays have a few bad pixels scattered across the screen

Other Types of Display

• 1. Projector

• 2. Plasma

Rear or reflective projection display system

Front or transmissive projection display systems

Plasma Display

Advantage

• High intensity light (Much more bright)

• Large screen with less thickness.

Printers

• A. Black and White

• B. Color

• 1. Ink-jet

• 2. Laser

• 3. Dot Matrix

• An inkjet printer is any printer that fires extremely small droplets of ink onto paper to create an image. If you've ever looked at a piece of paper that has come out of an ink jet printer, you know that:

• The dots are extremely small (between 10 and 30 dots per millimeter).

• The dots are positioned very precisely. • In color printers, the dots can have

multiple colors.

Laser Printer

Dot Matrix Printer

• It still is a common printer in business and large computers.

• The advantages for this kind is:

• 1. They can be made very quick.

• 2. They can be made big to print on wide papers.

Modem

• 1. Problems associated with long distance transmission.

• 2. Three different types of modulation.

• 3. Speed of modem-28.8kbps-57.6kbps

• 4. Full-duplex, half-duplex and simplex.

Brief History• 300 bps - 1960s through 1983 or so • 1200 bps - Gained popularity in 1984 and 1985 • 2400 bps • 9600 bps - First appeared in late 1990 and early

1991 • 19.2 kilobits per second (Kbps) • 28.8 Kbps • 33.6 Kbps • 56 Kbps - Became the standard in 1998 • ADSL, with theoretical maximum of up to 8

megabits per second (Mbps) - Gained popularity in 1999

DSL-Digital Subscriber Line

Advantages• Here are some advantages of DSL: • You can leave your Internet connection

open and still use the phone line for voice calls.

• The speed is much higher than a regular modem (1.5 Mbps vs. 56 Kbps)

• DSL doesn't necessarily require new wiring; it can use the phone line you already have.

• The company that offers DSL will usually provide the modem as part of the installation.

Disadvantages

• But there are disadvantages:

• A DSL connection works better when you are closer to the provider's central office.

• The connection is faster for receiving data than it is for sending data over the Internet.

• The service is not available everywhere.

ASCII and UNICODE

• We should all familiar with the ASCII code.

• 1. Background for UNICODE

• 2. The basic idea:

• a. Assign every char. And symbol a unique, permanent 16-bits value-- a code point.

• b. No multibyte characters and no escape sequences are used.

Main Advantage

• 1. It makes software writing simpler.

• 2. It makes transfer information between different country easier.

• 3. ASCII becomes Latin-1 in UNICODE.

•