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  1. 1. Secondary Storage <ul><li>What is a cylinder? A track? </li></ul><ul><li>What is secondary storage? </li></ul><ul><li>What is flash memory? </li></ul><ul><li>See Unit B in your Concepts Book </li></ul>Course Guide p. 255
  2. 2. What is (Auxiliary) Storage? <ul><li>CD-ROM </li></ul><ul><li>Tape Backup </li></ul><ul><li>Hard disk </li></ul><ul><li>Zip Drive </li></ul><ul><li>Floppy Disks </li></ul><ul><li>DVD </li></ul>RAM primary storage main memory, Needs power ROM is built in, Can change only slightly
  3. 3. Booting a computer uses ROM <ul><li>Bootstrapping: “to lift yourself up by your own bootstraps.” </li></ul><ul><li>ROM is built-in memory, doesn’t change, needed when the power comes on. </li></ul><ul><li>BIOS is a kind of Flash Memory, and can have some settings changed. Its name comes from basic input/output system ( BIOS ) </li></ul><ul><li>Finally, software loaded into RAM </li></ul>
  4. 4. Size of storage <ul><li>A binary digit; 0 or 1 = a Bit </li></ul><ul><li>8 bits, or one character = a Byte (used for one letter) </li></ul><ul><li>1000001 is the letter A (65 in ASCII) </li></ul>
  5. 5. Thinking of storage <ul><li>The letter A is one byte </li></ul><ul><li>1 GB is like 1 billion letter A's. </li></ul><ul><li>What if you could transfer one letter in each second? </li></ul><ul><li>If there are 31,557,600 seconds in a year, and it would take about 31 years and seven months to transfer 1 GB of information that way! </li></ul>
  6. 6. More…. <ul><li>a Bit True or False </li></ul><ul><li>a Byte used for one ASCII letter </li></ul><ul><li>1 Kilobyte capacity of a standard UIUC ID </li></ul><ul><li>1 Megabyte roughly a minute of compressed music </li></ul><ul><li>1 Gigabyte 18 hours of MP3 music </li></ul><ul><li>1 Terabyte 6 minutes of UHDV data </li></ul>
  7. 7. Units of Measure of Storage <ul><li>A binary digit; 0 or 1 = a Bit </li></ul><ul><li>8 bits, or one character = a Byte </li></ul><ul><li>1024 Bytes = 1 Kilobyte </li></ul><ul><li>1024 Kilobytes = 1 Megabyte (1024*1024) </li></ul><ul><li>1024 Megabytes = 1 Gigabyte </li></ul><ul><li>1024 Gigabytes = 1 Terabyte </li></ul>
  8. 8. Secondary Storage Devices <ul><li>Provide permanent storage </li></ul><ul><li>Slower to access than RAM </li></ul><ul><li>Direct access </li></ul><ul><ul><li>Magnetic Storage </li></ul></ul><ul><ul><ul><li>Removable (Floppy disk/diskettes) </li></ul></ul></ul><ul><ul><ul><li>Fixed (Hard disk) </li></ul></ul></ul><ul><ul><li>____________Disk (CD) </li></ul></ul><ul><li>Sequential access </li></ul><ul><ul><li>Magnetic ___________ </li></ul></ul><ul><ul><ul><li>Used for cassettes, archives </li></ul></ul></ul>
  9. 9. Disk Organization <ul><li>Tracks : Concentric circles where data is stored </li></ul><ul><li>Sectors : Pie-shaped wedges of tracks </li></ul>
  10. 10. Storing data on a hard drive
  11. 11. Disk Organization Track 00 Track 39 Track s and __________ Access Arm
  12. 12. Hard Disk Organization <ul><li>Cylinder : Combination of same-track locations </li></ul><ul><li>on multiple-surface disks </li></ul>
  13. 13. Formatting a disk, losing your data <ul><li>When you format a disk, the operating system erases all bookkeeping information on the disk, tests the disk to make sure all sectors are reliable, marks bad (damaged) sectors, etc. You must format a disk before you can use it. </li></ul><ul><li>Reformatting a disk does not erase the data on the disk, only the “directory” to find files. </li></ul>
  14. 14. CDs <ul><li>Digital </li></ul><ul><li>to </li></ul><ul><li>Analog </li></ul>
  15. 15. Solid state storage and its advantages <ul><li>Flash memory in cameras and phones and home video game players, as secondary storage rather than RAM </li></ul><ul><li>CompactFlash or SmartMedia cards are examples </li></ul>
  16. 16. Why not use Flash Memory everywhere? <ul><li>Flash memory is noiseless. </li></ul><ul><li>It allows faster access. </li></ul><ul><li>It is smaller in size. </li></ul><ul><li>It is lighter. </li></ul><ul><li>It has no moving parts. </li></ul><ul><li>BUT: </li></ul><ul><li>You can buy a 40-gigabyte (40,000-MB) hard drive for less than $200, while a 192-MB CompactFlash costs more! </li></ul>
  17. 17. Since we are talking about Flash memory, what is a Smart Card? <ul><li>The term Smart Card is loosely used to describe any card with a capability to relate information </li></ul><ul><li>Magnetic stripe </li></ul><ul><li>Memory, optical </li></ul><ul><li>Microprocessor cards </li></ul>
  18. 18. Memory card with a magnetic stripe – Memory is rewritable <ul><li>Your i-card has a cash stripe on the back of the card. </li></ul><ul><li>The dollar value placed on this stripe can be used to make copies and for some campus purchases. </li></ul><ul><li>You add funds to the stored value stripe through many of the Value Card Teller machines </li></ul>
  19. 19. Sim Cards <ul><li>A smart card fitted in every modern mobile phone which stores the phone's identity and settings. </li></ul><ul><li>Phone numbers can be stored on the card </li></ul><ul><li>Its primary function is to allow the networks to identify your phone to make calls. </li></ul><ul><li>You can move the sim card from phone to phone, taking your info with you </li></ul><ul><li>YOU CAN BACK UP YOUR SIM CARD, IN CASE YOUR CELLPHONE IS LOST! </li></ul>
  20. 20. Intelligent Smart Cards <ul><li>See definition: </li></ul><ul><li>Smart cards must have a central processing unit (CPU), random access memory (RAM), read only memory (ROM), and storage. </li></ul><ul><li>The card not the terminal executes the series of commands and sends the results to the terminal </li></ul>
  21. 21. How are they used? <ul><li>Electronic purses (EP): smart cards which have stored value of electronic cash. </li></ul><ul><ul><li>No authentication is necessary </li></ul></ul><ul><ul><li>Cards can be charged at special dispensers or by telephone and can be locked by a four digit code </li></ul></ul><ul><ul><li>Can store value in up to five currencies </li></ul></ul><ul><li>Secure transactions—storing biometric data, etc. </li></ul>
  22. 22. Where do they get the power from? <ul><li>Smart cards rely on electricity from a smart card reader for the power they need to run. </li></ul><ul><li>Wireless smart cards do not require electricity; instead, they have a built-in antenna that absorbs energy from nearby short-range electromagnetic fields. </li></ul><ul><li>Thus, everyday objects can be made intelligent via &quot;smart&quot; devices. </li></ul>
  23. 23. PC cards (USB Flash cards) <ul><li>PC Cards are credit card-size peripherals that add memory, mass storage, and other capabilities to computers—you plug them into the side of your laptop, usually. </li></ul><ul><li>Examples: </li></ul><ul><li>Hard Drives </li></ul><ul><li>Joystick Interface Cards </li></ul><ul><li>Memory Cards - Flash, SRAM, and many others </li></ul><ul><li>Modem and Ethernet Combination Cards </li></ul>
  24. 24. Preset stations on your car’s radio <ul><li>If you turn the ignition off, a car radio still pulls a tiny amount of current from the battery. It saves its data in its RAM. (called also Flash RAM) </li></ul><ul><li>That is why the car radio will lose its preset stations if your car battery dies or the wires are disconnected. </li></ul><ul><li>Car radios ought to use Flash Memory —maybe one day they will. </li></ul>