This document discusses different types of storage systems including hard disk drives, optical drives, portable storage devices, network drives, and remote storage. It explains that hard disk drives are most commonly used for permanent storage due to their high data transfer rates and storage capacities. Optical drives like CD and DVD drives allow data to be burned to portable discs for backup or sharing purposes. Other options include removable drives, network server storage, and remote online storage through an ISP.

1. Lesson 3: Working with Storage Systems
• storage systems
• hard disk drives
• optical drives
• portable or removable storage devices
• network drives
• remote storage
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2. What Are Storage Systems?
• RAM is temporary so you must save work to storage
device
• Storage device you use depends on amount of storage
you need and speed of data retrieval or data transfer rate
• Hard disk drives used most often to store and retrieve
software programs and data
• Can use other media such as flash drive or optical disc for
backup or portability purposes
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3. Working with Disk Drives
• Disk drive performs three functions:
− Rotates disk at constant speed to access sectors on entire disk
surface
− Moves read/write head across tracks on entire disk surface
− Reads data from disk and writes data to disk using read/write head
• Data from RAM written on disk arranged in tracks divided
in sectors
• Process of preparing disk for use is called formatting
− Places special information on each track that marks location of
each sector
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4. Working with Hard Disk Drives
• Primary storage area for both data and programs
− Software programs must be installed on hard drive
− Hard drive stores and retrieves information at high speeds
• Data transfer rate (throughput) of hard drive is function of
hard drive rotation speed and number of heads per surface
− The higher the rotation speed and/or number of heads,
the less time it takes to find data
− Range in capacity from 100 MB to 100+ GB
− Also used in network servers where drives very large to
accommodate requirements of whole organization and data
storage requirements
− Data transfer rate quite fast although can be restricted by type of
network interface cards and number of users or tasks to be processed
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5. Working with Optical Drives
• Designed to read flat, circular disc, commonly referred to as
Compact Disc (CD) or Digital Versatile/Video Disc (DVD)
− Read by laser device or optical drive that spins disc at speeds from
200 rpm or higher
• CD-ROM (Compact Disc Read Only Memory) or DVD-ROM
drive
− Similar to player in audio/video entertainment system
− Information written or burned onto surface and retrieved with laser
beam
− Can only read data
• New computers come with at least one optical drive
− Usually DVD optical drive or CD/DVD optical writer drive.
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6. Optical Writers
• Also known as burner drive, looks and acts like regular optical disc
drive
− Software comes with optical writer drive to “burn” or write data onto a disc
• Formats of drives include:
− CD-R/ DVD-R: can write once only to blank disc, but disc can be read
multiple times
− CD-RW/ DVD-RW: can read and write multiple times onto same disc
− DVD-RAM: similar to DVD-RW but can only be used on devices that
support this format; usually in the form of cartridges
• Blank discs relatively inexpensive, with -R disks cheaper than -RW
• Size of disc can be 650 or 700 MB, while DVDs can be 4.7GB to
17+GB with rapid access speeds
• Special software needed to manipulate or edit video before burned to
DVD
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7. Using Other Types of Storage Devices
• Tape drive or tape streamer uses cartridge with magnetic tape
− Generally used to back up large amount of data
− Use different formats, with tape sizes ranging from 250MB to over 80GB
− Other tape drives use Digital Audio Tape (DAT) format
• Zip drive similar to DVD-RAM drive except that disk can hold
between 100MB and 750MB data
− Offers relatively inexpensive storage option
− Newer systems not compatible with original 100MB devices
• Removable media systems can include flash memory cards,
sticks or USB flash key/thumb drives, or external hard drives
− Benefits include portability, large storage size, and data-sharing capability
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8. Using Other Types of Storage Devices
• Hard drives in network server similar to hard disk drives in
computer
− Traditionally much larger than available with desktop computer
− May be set as disk array, as drives usually organized to work
together
• Remote or virtual storage systems do not exist on your
computer or location
− Common service provided by Internet Service Providers (ISP)
− Drives on network or dedicated server at particular site
− Must login to with secure ID and password to access information
− Very useful for off-site backup storage of data, or as “central
system” for people in multiple locations to share information
− Disadvantage can be speed of Internet connection
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9. Lesson Summary
• storage systems
• hard disk drives
• optical drives
• portable or removable storage devices
• network drives
• remote storage
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