CSIS 2810

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CSIS 2810
2012-03-07 22:44:06

CSIS 2810 Midterm terms
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  1. Moor's Law
    The transistor count on an IC will double every 18 to 24 months.
  2. Amdahl's Law
    The performance enhancement is limited to the amount that the improvement is used.
  3. Performance
    • A broad scope term used in describing the overall ability for a computer to exicute a program.
    • Or, Performance = 1 / Execution time
  4. CPU speed
    The frequency that the processor runs at
  5. CPI
    • Cycles per instruction
    • CPI = CPU Clock cycles / Instruction count
  6. Seek
    The process of positioning a read/write head over the pproper track on a disk.
  7. Tracks
    Concentric circles that makes up the surface of a magnetic disk
  8. Sectors
    Segments that make up a track on a magnetic disk.
  9. Platters
    Something you put shrimp salads on.
  10. Rotational Latency
    The time it takes for the read/write head to locate the proper sector within a track.
  11. Polling
    The processor continually checks the I/O device to determine if the I/O device has a request for the CPU.
  12. Interrupt
    An Interrupt driven I/O sends an interrupt flag to the CPU to tell the CPU that it has a request of services from the CPU. This eliminates the need for the CPU to continually poll the devices.
  13. Direct Memory Access. (DMA)
    DMA is a process where a DMA controller provides the ability to transfer data to and from the memory without putting a load on the processor.
  14. RAID 0
    RAID 0 is used simply for speed but has no redundancy.
  15. RAID 1
    RAID 1 uses mirroring to make a duplicate of the hard drive on another. Used for redundancy.
  16. RAID 2
    RAID 2: uses error detection and correction.
  17. RAID 3
    RAID 3: Uses a parity check on an additional drive to rebuild any failures.
  18. RAID 4
    RAID 4: Uses block parity similar to RAID 3.
  19. RAID 5
    RAID 5 (JBOD) A combination of RAID 0 and RAID 3. It has the speed of RAID 0 bit with parity redundancy of RAID 3. Hard disks can be of any size as parity blocks can be located on any disk.
  20. RAID 6
    RAID 6: Multiple check blocks are in place for failure detection.
  21. Block
    The minimum unit of information that either can or can’t be present in a cache.
  22. Hit
    Requested data located in some block in the upper level.
  23. Miss
    Requested data not located in some block in the upper level.
  24. Word
    A term for the natural unit of data used by a particular processor design. Usually a fixed bit size. 32-bit for mips.
  25. Index
    Part of a memory address in a block.
  26. Tag
    • 1.
    • A field in a table that used to identify whether
    • the associated block in the hierarchy corresponds to a requested word.
  27. Write through
    A scheme designed for consistency where data is always written to both the main memory and the cache.
  28. Write back
    A write-back handles writes by updating values only to the block in the cache, then writing the modified block to the lower level of the hierarchy when the block is replaced.
  29. Page
    A virtual memory block.
  30. Page table
    The table containing the virtual to physical address translations in a virtual memory system.
  31. Translation-lookahead buffer
    A cache that keeps track of reciently used address mappings to try to avoid an access to the page table.
  32. Page fault
    A miss on the block is a page fault.
  33. Virtual address
    A virtual address is a location in virtual memory which is translated by hardware and software into a physical address.
  34. Physical address
    The physical address can be used to access the memory.