Chapter 7 and 8  - Notes

Storage - nonvolitile sotrage medium such as USB hard drive, CD's DVD's and microfilm

Storage capacity reminders:

    KB (kilobyte)  1024 bytes, but generally rounded to 1000
    MB (megabyte) 1 million bytes
    GB (gigabyte) 1 billion bytes
    TB (terabyte) 1 trillion bytes
    PB (petabyte) 1 quadrillion bytes
    EB (exabyte) 1 quintillion bytes
    SB (zettabyte) 1 sextillion btes
    YB (yottabyte) 1 septillion bytes

Typical flash or USB drives traditionally hold ___________

Magnetic disks

    tracks -

    sectors -


Current hard drives store between 80-750GB+
Hard drives can be read and written to
Depending on size,hard drives usually contain multiple platters
Each platter has 2 read/write heads, one for each side
Drive designation is usually "C"
Floppy disk drive is usually "A"
Portable and removable drives offer many advantages such as:


Optical discs - store susing pits (indentations and lands (flat areas)

Types of optical disk formats:

CD-ROM -


CD-R -(no erase)


CD-RW -

DVD's have higher storage capacities than CD's and store images at a higher resolution

DVD-ROMs -


DVD-R and DVD+R (competing recordable formats)


DVD-RW, DVD+RW and DVD+RAM (competing formats) -


Magnetic Tape - what is it used for?


Sequential access vs random or direct access -





Smart cards, picture cards, memory sticks etc -

 
Operating systems definition -



Starting or booting a computer:

Step one - turn computer on, power supply sends electronic signal to the components in the system unit

Step two - The electrical charge causes the processor chip to resetitself and find the ROM chip that contains the BIOS

Step three - BIOS executes hardware tests called POST which checks system components

Step four - POST results are compared with data on CMOS chip

Step five - If POST completes successfully, the BIOS searches for the system files of the O/S  

Step Six - system files loaded into RAM

Step seven - O/S loads configuration information.

What is the command line interface?

Single tasking operating system compared to multi-tasking operating system-

Operating system utility programs -
    file manager
    search utility
    image viewer
    personal firewall
    uninstaller
    disk defragmenter
    screen saver

Examples of non-operating system utility programs -


Examples of operating systems: