2. CSCI-100 Introduction to Computing Hardware Part II

3. © Prentice-Hall, Inc Digitizing the Real World  Scanner  Digital camera  Speech recognition  Sensing devices  Audio and video digitizers

4. Continuous & Discrete Signals

5. © Prentice-Hall, Inc Audio Input  Computers can accept input from a microphone  An expansion card called a sound card records and plays back sound files  Sound files contain digitized sound data  Popular sound file formats include: Windows WAV Windows WAV Moving Pictures Expert Group (MPEG) Moving Pictures Expert Group (MPEG) MP2 and MP3 MP2 and MP3 Musical Instrument Digital Interface (MIDI) Musical Instrument Digital Interface (MIDI)

6. © Prentice-Hall, Inc Audio Digitizers  Audio digitizers capture spoken words, music and sound effects and convert them to digitized sounds  These sounds can be stored in a computer’s memory and modified with computer software

7. Sound Card  Functions: facilitates the input and output of audio signals to and from a computer under control of computer programs play previously recorded sound (translates a digital file into sound) play previously recorded sound (translates a digital file into sound) to record new sound (translate sound into a digital file) to record new sound (translate sound into a digital file)

8. © Prentice-Hall, Inc Digital Cameras Digital Video Digital Input: Digital Cameras and Digital Video

9. © Prentice-Hall, Inc Video Digitizers Video digitizers capture input from video sources such as video camera and convert it to a digital signal that can be stored in memory and displayed on a computer screen Video digitizers capture input from video sources such as video camera and convert it to a digital signal that can be stored in memory and displayed on a computer screen

10. Data Representation Binary Numbers!!! Sound  pitch  number  binary number Sound  pitch  number  binary number Letter  number  binary number Letter  number  binary number Image  color at each pixel  number  binary number Image  color at each pixel  number  binary number

12. Data Representation But how many bits are needed to store n symbols? Or, how many bits are needed to represent n numbers? log 2 n

13. © Prentice-Hall, Inc Output Devices: Engaging our Senses  Output devices are peripheral devices that enable us to view or hear the computer’s processed data Visual output – Text, graphics, and video Visual output – Text, graphics, and video Audio output – Sounds, music, and synthesized speech Audio output – Sounds, music, and synthesized speech

14. © Prentice-Hall, Inc Monitors  A monitor is a peripheral device which displays computer output on a screen  Types of monitors: Cathode-ray tube (CRT) Cathode-ray tube (CRT) Liquid Crystal Display (LCD or flat-panel) Liquid Crystal Display (LCD or flat-panel) CRT LCD

15. © Prentice-Hall, Inc Cathode-ray tube (CRT)  Resemble televisions  Use picture tube technology  Less expensive than a LCD monitor  Take up more desk space and use more energy than LCD monitors

16. © Prentice-Hall, Inc Screen Talk  Monitor size - measured as a diagonal line across the screen  Pixels (or picture element) - tiny dots that compose a picture  Resolution - the number of pixels displayed on the screen (the higher the resolution, the closer together the dots)

17. © Prentice-Hall, Inc Monitor Specifications  Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21)  Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)  Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)

18. © Prentice-Hall, Inc Image Quality  Image quality is affected by resolution and color depth (or bit depth)  Color depth refers to the number of bits used to represent a pixel.

19. © Prentice-Hall, IncPrinters  A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output

20. © Prentice-Hall, Inc Inkjet Laser Types of Printers  Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper  Letter-quality printouts  Cost of printer is inexpensive but ink is costly  Laser printer works like a copier  Quality determined by dots per inch (dpi) produced  Color printers available  Expensive initial costs but cheaper to operate per page

21. Modem  Connects you computer to the outside worlds  Modulate - Converts a digital signal into an analog one  Demodulate - Converts an analog signal to a digital one.  Modem = Modulate demodulate  Example

22. Modem  Speed is measured in BPS (Bits per second)  Standard speed is 56k BPS

23. © Prentice-Hall, Inc Storage Devices  Storage devices are categorized by: The type of operations they perform The type of operations they perform The method they use to access the information The method they use to access the information The technology they use The technology they use Their location in the storage hierarchy Their location in the storage hierarchy Their capacity and speed Their capacity and speed

24. © Prentice-Hall, Inc Sequential vs. Random Access Storage  Sequential – Storage devices that read and write data in a serial (one after the other) fashion  Random-Access – Storage devices that read and write data without going through a sequence of locations Tape Drive – sequential storage Hard Disk – random-access storage Floppy Disk Drive – random-access storage

25. © Prentice-Hall, Inc Storage Technologies: Magnetic and Optical  Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material  Optical – Storage devices that use laser beams to read patterns etched into plastic disks Magnetic Storage Optical Storage – CD/DVD drive

26. © Prentice-Hall, Inc Optical Disk Storage  Microscopic indentations called pits scatter the laser beam’s light. A light-sensing device receives no light from the pits. A signal is sent to the computer corresponding to a 0 in the binary system  Flat, reflective areas, called lands, bounce the light back to the light sensing device, which sends a signal corresponding to a 1 Cross-section of a disk Disk surface magnified

27. © Prentice-Hall, Inc CD-ROM Discs and Drives  CD-ROM stands for Compact Disc-Read Only Memory  CD-ROM drives can not write data to discs  They are capable of storing ~700 MB of data  They are used for storing operating systems, large application programs, and multimedia programs

28. CD-ROMs and Recordables  1st CD-ROMs had speeds of 600 millisecond access time and transfer rates of 150 KB.  32 times the original speed (32X).

29. © Prentice-Hall, Inc CD-R and CD-RW Discs and Recorders CD-R  Discs can be read and written to  Discs can only be written to “once”  CD-R drives are capable of reading and writing data CD-RW  Discs can be read and written to  Discs are erasable  Discs can be written to many times  CD-RW drives are capable of reading, writing, and erasing data

30. © Prentice-Hall, Inc DVD-ROM Discs and Drives  DVD stands for Digital Video Disc  DVD technology is similar to CD- ROM technology  DVDs are capable of storing up to 17GB of data  The data transfer rate of DVD drives is comparable to that of hard disk drives  DVD-R and DVD-RW drives have the ability to read/write data

31. Ports  Serial port: one bit at a time  Parallel port  USB port (Universal serial port): USB can connect computer peripherals (such as mice, keyboards, digital cameras, printers, personal media players, flash drives, Network Adapters, and external hard drives to the computer. USB can connect computer peripherals (such as mice, keyboards, digital cameras, printers, personal media players, flash drives, Network Adapters, and external hard drives to the computer. For many of those devices, USB has become the standard connection method. For many of those devices, USB has become the standard connection method. USB was designed for personal computers, but it has become commonplace on other devices such as smartphones, PDAs and video game consoles, and as a power cord. USB was designed for personal computers, but it has become commonplace on other devices such as smartphones, PDAs and video game consoles, and as a power cord.  Other types of ports. © Prentice-Hall, Inc