Comp Sci 1BA3 Test #2 Review

Comp Sci 1BA3 Test #2 Review - Comp Sci 1BA3 Review#2...

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Comp Sci 1BA3 Review #2 Unit #3: Storage Storage Device: A piece of hardware, such as a floppy drive or CD drive, into which a storage medium is inserted to be read from or written to. Example: CD-ROM Drive, Floppy Drive - Can be internal (inside the computer), external (outside the computer) or remote (located on another computer like a server) Storage Medium: The part of a storage system where data is stored, such as a floppy disk or CD disc - Storage medium is volatile, therefore, when you shut down your computer and turn it on again, the information you stored on them is still there. This is the opposite of RAM. Random Access: data can be retrieved directly from any location on the storage medium. Example: disk drives, floppy discs, CDs Sequential Access: Data can only be retrieved iin the order in which it is physically located on the medium Logical Representation: Certain areas of a disk serve the special purpose of being used by only the operating system Physical Representation: Access data stored on the storage media using its physical location Magnetic Disks: A storage medium that records data using magnetic spots on disks made of flexible plastic or rigid metal. Example: Floppy disc and hard drive - Data is written by read/write heads which magnetize particles a certain way on a medium’s surface to represent the data’s 0’s and 1’s - Round piece of flexible piece of plastic coated with a magnetized substance - The surface is organized by circular rings called tracks and pie-shaped sectors Hard Disc Drives: storage system consisting of one or more metal magnetic disks permanently sealed with an access mechanism - Uses read/write heads like floppy disks - Disks used with a hard drive are made with metal and are permnaneltly-sealed Hard Drive Speed and Caching 1. Move the read/write heads to the cylinder that contains the data – seek time 2. Rotate disks into proper position so that the read/write heads are located over the part of the cynclinder to be used – rotational delay
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3. Move data, transfer it to memory, etc – data movement
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This note was uploaded on 08/04/2008 for the course COMP SCI 1BA3 taught by Professor Ebrahim during the Fall '08 term at McMaster University.

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Comp Sci 1BA3 Test #2 Review - Comp Sci 1BA3 Review#2...

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