Removable Media

• Bits, Bytes, Meg and Gig
  • You should read the first 21 pages of Essential Computing Concepts.
    • You really should read the entire thing.
    • Pay attention to Bits and Bytes, Memory, and Auxiliary Storage
  • The primary unit of storage in a computer is a bit.
    • This stands for Binary digIT
    • and is either a 0 or a 1.
    • But we don't use this measure very often
    • because it is too small.
    • But combinations of bits add up quickly.
    • Example naming students with a bit, or a bit pattern.
  • A collection of 8 bits is a BYTE
  • For most things, this is the basic unit of measurement.
  • Memory, disk space, file sizes ...
  • But it takes a bunch of bytes to do anything, so we group them as well
  K, M, G
  • Kilo - Greek for thousand, normally 10³ or 1000
  • In computing we use the term for 2¹⁰ or 1024
  • So 1 kilobyte, or 1KB is 1024 bytes, or 8x1024 bits
  • We don't measure much in KB these days, just modem speeds (28.8 K bps), and cache sizes.
  • Mega - Greek for mighty, normally 10 ⁶ or 1,000,000 (a million)
  • When measuring memory, we use the term to refer to 2²⁰ or 1,048,576
  • So 1 megabyte, or 1MB is 1,048,576 bytes 8x 1,048,576 bits.
  • This is currently the most common unit for removable storage and main memory in a personal computer.
    • Floppy disks are about 1.5 MB
    • CDs can hold around 600 MB
    • A zipdisk can hold 100, 200, or 750 MB
    • USB drives can hold from 15 - 512 MB (or more)
    • Most new personal computers have between 128 and 512MB of main memory.
  • Giga - Greek for giant, normally 10⁹ or 1,000,000,000
  • When measuring memory, we use the term to refer to 2³⁰ or 1,073,741,824
  • We measure disk space in gigabytes (GB)
    • Today most new computers have between 20GB and 160GB of hard drive space.
    • DVD disks can hold up 17GB
    • Some USB drives are in the 1GB range
  • There are other measurements, (tera, peta, ...)
    • They are in use now, and will drop to the pc world in most of our life times.
• Media for class:
  • If you plan to work exclusively on campus, you can use your university disk space to store work for this class.
  • If you plan to work at home, you will need to store your work on removable media.
  • Your media choices
    • Floppy - you would need at least 4-5 of these
      • + They are inexpensive
      • + They can be found everywhere
      • + Almost every computer has a floppy disk.
      • - they break easily (physically)
      • - They Break easily (electronically)
      • - they don't hold much data
    • Zip - you would need one of these.
      • + The machines in the lab have 750MB zip drives
      • + They will work with 200MB and 750MB zip disks
      • + The work well and are not too expensive ($10)
      • + They are hard to break, and don't fail often
      • - Most machines don't have such drives.
    • CD rewritables - you would need 1 of these.
      • + They are very inexpensive
      • + They don't fail very often
      • - they are somewhat difficult to use (not bad)
      • - you need a cd writer at home, but most machines have these
    • USB drive - you would need one of these.
      • + They come in a variety of sizes
      • + They are GREAT
      • +/- They are moderately prices (free - $hundreds)
      • - You need a usb port to use these, but most machines have these.
• The media you need to buy will depend on what you want to do and what computing resources you will use. If you are confused, please see me or the graduate assistant.