IS310 Exam 3 Chap 5 Vocab

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IS310 Exam 3 Chap 5 Vocab
2011-11-21 02:15:21
IS310 Exam Chap Vocabulary

Vocab for Chap 5
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  1. Access arm
    in magnetic disks, the device where read/write heads are mounted; it's attached to a positioning servo for placing read/write heads on specific tracks
  2. Access time
    the time required to perform one complete read or write operation; a measure of storage device time
  3. Advanced Intelligent Tape (AIT)
    a magnetic tape standard developed by Sony based on Digital Audio Tape; uses helical scanning and an improved tape drive tech to pack more data onto a single tape. AIT includes a small RAM cache in cartridge, which stores directory info. to speed searching and data access.
  4. Areal density
    the surface area allocated to a bit on a storage medium, typically measured in bits, bytes, or tracks per inch
  5. Average access time
    typically expressed as an average of access time for all storage locatiosn
  6. Block
    a generic term for describing secondary storage data transfer units. also refers to a set of logical records grouped on a storage device for efficient processing , storage, or transport as well as a portion of a program that's always executed as a unit.
  7. Blu-ray Disc (BD)
    An update to DVD-ROM, orginally designed for high-definition video discs but has been adapted to data storage
  8. CD digital audio (CD-DA)
    a read-only format for storing and distributing music on a CD
  9. CD read-only memory (CD-ROM)
    a standard 120-mm read-only optical disc; compatible with CD-DA but includes additional formattng info. to store directory and file info.
  10. Coercivity
    the capability of a substance or magnetic storage medium to accept and hold a magnetic charge; directly proportional to mass
  11. Compact disc (CD)
    a technology developed by Sony and Phillips for storing and distributing musicin the CD-DA format on a 120-mm optical disc
  12. Core memory
    in early computers, a technology for implementing primary storage as rings of ferrous materials embedded in a two-dimensional wire mesh
  13. Cylinder
    in magnetic disks, consists of all tracks at an equivalent distance from the edge or spindle on all platter surfaces
  14. Data transfer rate
    the rate at which data is tranmitted through a medium or communication channel; measured in data units per time interval; essentially, it's measure of communicaiton capacity. For storage device, it's computed by dividing 1 by the access time and multiplying the result by the unit of data transfer
  15. Digital Audio Tape (DAT)
    an early magnetic tape tech on which Digital Data Storage standards are based
  16. Digital Data Storage (DDS)
    magnetic tape standards developed by Hewlett-Packard and Sony and based on Digital Audio Tape; DDS drives use helical scanning
  17. Direct access
    see random access
  18. Disk deframentation
    reorganizing data on a disk data so that a file's contents are stored in sequential sectors, tracks, and platters; an OS utility us used to perform this task
  19. Double data rate (DDR)
    a series of techs, each doubling the data transfer rate of the previous synchronous DRAM versions
  20. Double inline memory module (DIMM)
    a small printed circuit board that essentially a SIMM with independent electrica contacts on both sides of the module.
  21. Drive array
    an arrangement of hard drives enclosed in a storage cabinet and accessed as though they're a single storage devices
  22. Dual inline packages (DIPs)
    an early form of packaging for RAM or ROM circuits; had two rows of electrical contact pins
  23. DVD
    An optical disc format for distributing movies and other audiovisual content; stands for both digital video disc and digital versatile disc
  24. DVD read-only memory (DVD-ROM)
    a format for general-purpose read-only data storage on a DVD
  25. Dynamic RAM (DRAM)
    a type of RAM that stores each bit by using a single transistor and capacitor
  26. Electronically erasable programmable ROM (EEPROM)
    a type of nonvolatile memory that can be programmed, erased, and reprogrammed by signals snet from a CPU; the only type of ROM that's currently used
  27. Erasable programmable ROM (EPROM)
    a type of nonvolatile memory that's manufacutured blank, written (programmed) with aspecial EPROM writer, erased by exposure to ultraviolted light
  28. Firmware
    Software, such as system BIOS, stored in nonvolatile memory; can be loaded into main memory at high speeds
  29. Flash RAM
    the most common type of nonvolatile memory; typically used to store firmware and in portable secondary storage systems, such as USB flash drives
  30. Fragmented
    the condition of a hard disk (or other storage drive) with many programs and files scattered across it in noncontiguous storage locations.
  31. Germanium, antimony, and tellurium (GST)
    a glasslike compound, used in phase-change memory, that can change between amorphous and crystalline states
  32. Hard disk
    a magnetic disk medium with a rigid metal base (substrate) where data is recorded as patterns of magnetic storage
  33. Head-to-head (HTH) switching time
    the time needed to switch a hard drive's read/write circuitry to the correct read/write head before accessing a sector
  34. Helical scanning
    a geometric approach to recording data on a tape surface in which data is read and written by rotating the read/write head at an angle and moving from tape edgeto tape edge
  35. Linear recording
    a geometric approach to recording data on a tape surface in which bits are placed along parallel tracks that run along the tape's entire length
  36. Linear Tape Open (LTO)
    a magnetic tape standard developed by Hewlett-Packard, IBM, and Seagate; uses linear recording and has tech improvements in tape cartridges, coercible materials, read/write heads, and tape control
  37. Magnetic decay
    the tendency of magnetically charged particles to lose their charge over time; it's constant over time and proportional to the power of the charge
  38. Magnetic leakage
    the reduction in strength of a stored magnetic charge because of interference from adjacent magnetic charges of opposite polarity
  39. Magnetic tape
    a ribbon of plastic with a coercible (usually metallic oxide) coating, used to store data
  40. Magneto-optical (MO) drive
    a secondary storage device that uses a laser and reflected light to sense magnetically recorded bit values; data reading is based on the polarity of the reflected laser light, which is determined by the polarity of the magnetic charge
  41. Magnetoresistive RAM (MRAM)
    a type of nonvolatile memory under development that stores bit values by using two magnetic elements, one with fixed polarity and the other with polarity that changes when a bit is written; has better longetivity than conventional flash RAM
  42. Mammoth
    a magnetic tape standard, developed by Exabyte, based on Digital Audion Tape; uses helical scanning and an improved tape drive tech. to pack more data onto a single tape
  43. Nonvolatile
    a term describing storage devices that hold data without loss for long periods; secondary storage is usually nonvolatile
  44. Nonvolatile memory (NVM)
    a generic term for memory devices with long-term or permanent data retention
  45. Parallel access
    an access method that can access multiple storage locations simultaneously; can also be achieved by subdividing data items and storing the component pieces on multiple storage devices
  46. Phase-change memory (PCM)
    a type of nonvolatile memory under development that uses a GST compound capable of switching between amorphous and crystalline states; has fast write times and high longevity
  47. Platters
    in magnetic disk media, they're flat, circular disks with metallic coatings that rotated beneath read/write heads; data is normally recorded on both sides
  48. Quarter Inch Committee (QIC)
    a committee that develops open standards for magnetic tape drives on smaller computers.
  49. Random access
    an access method that can access any storage location directly and in any order; primary storage devices and disk storage devices use random access
  50. read-only memory (ROM)
    the earliest type of nonvolatile memory, which data content written permanently during manufacturer; this primary storage device can be read, but no further data can be written
  51. Read/write head
    a mechanism in a storage device that reads and writes data to and from the storage medium
  52. Refresh cycle
    in dynamic RAM, the period during which circuitry supplies fresh infusions of power automatically; read and write operations can't be performed during this cycle. Also refers to the transfer of a full screen of data from the display generator to the monitor
  53. Rotational delay
    the time a hard disk controller must wait for the right sector to rotate beneath read/write heads
  54. Sector
    the data transfer unit for magnetic disk and optical disc drives; the size is generally stated in bytes and can vary from one device to another. Also refers to a fractional portion of a track on magnetic disk media.
  55. Sequential access time
    the time required to read the second of the two adjacent sectors on the same track and platter of a hard disk
  56. Serial access
    an access method that stores and retrieves data items in a linear (sequential) order; mainly used to hold backup copies of data stored on other storage devices
  57. Single inline memory module (SIMM)
    a small printed circuit board that incorporates mulitiple DIPs and has a row of electrical contacts on the edge; the entire package is designed to lock onto a SIMM slot on a motherboard
  58. Solid-state drive (SSD)
    a storage device that mimics the behavior of a magnetic disk but uses flash RAM or other nonvolatile memory devices as the storage medium and read/write mechanism; expected to replace magnetic disks gradually
  59. Static RAM (SRAM)
    a type of RAM that's implemented entirely with transistors; the basic storage unit is a flip-flop circuit
  60. Storage medium
    a device or substance in a storage device that actually holds data
  61. Super Digital Linear Tape (SDLT)
    a magnetic tape standard developed by Quantum Corporation; the cartridge has only one reel, and the device records in parallel linear tracks in an end-to-end format
  62. Sustained data transfer rate
    the maximum data transfer rata a storage device or communication channel can sustain during lenthly data transfer operations
  63. Synchronous DRAM (SDRAM)
    a read-ahead RAM that uses the same clock pulse as the system bus; read and write operations are broken into simple steps that can be completed in one bus clock cycle
  64. Tape drive
    a slow serial access device containing motors that wind and unwind tapes and read/write heads to access tape content
  65. Track
    one oncentric circle of a platter; the surface area that passes under a read/write head when its position is fixed
  66. Track-to-track (TTT) seek time
    the average time needed to move a read/write head between two adjacent tracks; typically measured in milliseconds
  67. Volatile
    a term describing storage devices that can't hold data for long periods; primary storage is usually volatile