1. Storing Data: Electronic Filing Cabinets What You Will Learn Difference between memory and storage How storage media are categorized Measuring a storage device’s performance How data is stored on hard and floppy disks Characteristics of hard drives Uses of removable disks Various optical storage media New storage media

2. What is the difference between memory and storage? Storage devices hold programs and data in units called files Files are stored in directories or folders Memory is a temporary workplace where the computer transfers the contents of a file while it is being used Hard Drive RAM memory

3. Why is storage necessary? Storage retains data when the computer is turned off Storage is cheaper than memory Storage plays an important role during startup Storage plays an input role when starting applications Storage is needed for output Storage devices can hold a large amount of data

4. What is a storage device? Hardware that is capable of retaining data when electricity is turned off Able to read (retrieve) data from a storage medium (disk/tape) Able to write (record) data to a storage medium

5. What are the types of storage technologies? Sequential- Hardware that reads and writes data in a serial (one after the other) fashion Random Access- Hardware that reads and writes data without going through a sequence of locations Magnetic- Hardware that uses disks or tapes that are coated with magnetic material Optical- Hardware that uses laser beams to read data from plastic disks Solid State- Devices that use nonvolatile memory chips to read and write data

6. Sequential – Magnetic Storage Random Access – Magnetic Storage Tape Backup Unit Floppy DriveHard DriveJaz DriveZip Drive

7. Sequential – Optical Storage CD ROM / DVD Drive Magnetic – Optical Storage Magneto-Optic (MO) Drive

8. Solid State Storage Compact Flash Memory Flash Memory Smart Card Micro Drive Memory Stick PC Card

9. How is a storage device’s performance measured? Capacity- The number of bytes of data that a device can hold Access Time- The amount of time it takes for the device to begin reading data; measured in milliseconds (ms) Floppy Disk Hard Drive CD ROM / DVD Capacity- 720KB to 1.44 MB Access Time- 100ms Capacity- Up to 80 GB Access Time- 6 to 12ms Capacity- CD Rom 650MB; DVD 17GB Access Time- 80 to 800ms

11. What are hard disk drives? A high speed, high capacity storage device Consists of metal disks called platters Contains two or more stacked platters with read/write heads for each side Works similarly to floppy disk drives

12. What affects a hard disk’s performance? Seek time or positioning performance- How quickly the read/write head positions itself and begins transferring information. Measured in milliseconds (ms) Spindle speed or transfer performance- How quickly the drive transfers data. Measured in rotations per minute (RPM)

13. What are hard disk interfaces? Enables the hard disk to communicate with the CPU by way of the hard disk controller Types of interfaces  Integrated Drive Electronics (IDE)- also called ATA or IDE/ATA  Serial ATA interfaces, also known as SATA150  Small Computer System Interface (SCSI)  FireWire/IEEE 1394

14. What is a removable hard disk? Platters are enclosed in a cartridge which can be inserted or removed from a drive Used for data archiving and data backup Usually connected via USB Jaz Drive

15. What is a tape backup unit? A device used to store large amounts of data that are not used frequently Uses cassette type reel to reel plastic tape Tape Backup Unit

17. What is a CD-ROM? Stands for compact disk-read only memory CD-ROM drives can not write data to disks Capable of storing 700MB of data Used for storing operating systems, large application programs, and multimedia programs

18. How does a CD-ROM drive work? Laser beams read microscopic patterns of data on the disk’s surface Disks contain indentations (pits) and flat reflective areas (land) The computer interprets the pits as 0’s and the lands as 1’s

19. What is CD-R and CD-RW? CD-R Disks that can be read and written to Disks can only be written to “once” Drives that are capable of reading and writing data CD-RW Disks that can be read and written to Disks are erasable Disks can be written to many times Drives that are capable of reading, writing and erasing data

20. What is DVD? Stands for digital video disk Uses similar technology as CD-ROM Capable of storing up to 17GB of data Data transfer rate comparable to hard disk drive Compatible with CD-ROM disks DVD-RAM- Ability to read/write data

22. What is solid state storage? Nonvolatile memory chips used to retain data Solid state storage devices do not have moving parts Solid state storage devices are small, lightweight, reliable, and portable

23. Types of solid state storage devices PC or PCMCIA card- Credit card sized device used mainly with notebook computers; Various functions (modem, adapter, memory and storage)

24. Types of solid state storage devices Flash memory card- Wafer thin card used with cellular phones, MP3 players, and digital cameras Types of flash memory cards- SmartMedia card, CompactFlash card, and Sony’s Memory Stick CompactFlashMemory StickSmartMedia

25. Types of solid state storage devices Smart card- Credit card sized device combining flash memory with a microprocessor; Used as a credit card; Has more functionality, convenience, and safety than credit cards

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