The more advanced the technology, the more primitive the tool needed to break it

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The more advanced the technology, the more
primitive the tool needed to break it
http//www.amazon.com/exec/obidos/tg/detail/-/B000
04WG7T/002-9936590-5259256?vglance

• Tom Baker in The Pirate Planet (1978)

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Computer Science 101Lecture 13
electronics.howstuffworks.com/ capacitor.htm

• Spring Semester 2008
• Monday, February 11
• Week 5/18
• Albert H. Carlson

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Announcements

• First exam is Friday, February 15. Get your HW
  done early.
• Due on February 15 Excel Project and the first
  set of HTML Layouts
• This week for Lab, bring your Excel project on
  your Flash drive

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Memory

• What is cache?

• Helps speed computer processes by storing
  frequently used instructions and data
• Also called memory cache

• L1 cache built into processor
• L2 cache slower but has larger capacity
• L2 advanced transfer cache is faster, built
  directly on processor chip
• L3 cache is separate from processor chip on
  motherboard (L3 is only on computers that use L2
  advanced transfer cache)

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Virtual Memory

• Your hard drive sometimes has open space on it
• That space can be used by the computer to run
  programs and store things that it wants to
  quickly retrieve
• This is called virtual memory
• Slower than chip, but faster than some hard drive
  accesses

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• Paging The action of using the space on the
  disk and changing swap files, when needed
• Swap Files Files saved and paged in and out of
  memory when needed

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Inside the Hard Drive
Sector
Track
Spindle
Head
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Access Time

• Total access time for a disk depends on the
  following
• Seek Time (very long)
• Rotational time (this is why the rpms are
  listed)
• Data transfer rate
• How much data is transferred
• Ttotal (Trot/30) Tseek (Size/Rate)

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A Comparison
Seek Time
Latency Time
Transfer Time
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Disk Naming

• The first disks were floppies
• They got named A, then duals A and B
• Then came the hard drive
• This got named the C\ drive
• Now there are other drives
• All other drives get labeled AFTER the C\ drive
• These include removable and additional hard
  drives

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Questions?