How Things are Measured(1)

Sometimes we loose our way in all those huge numbers. Here is a page to help you remembering.
Mind You! Whilst the rest of the world uses milliard the Americans use: Billion (2)

Definitions

BIT	Binary digit, smallest piece of information a computer can process
BYTE	8 bits
MICRON	One millionth of a meter, equal to 0.000039 inches
MIPS	Millions of instructions per second. An instruction is fetched, decoded, and executed.
REGISTER	A storage location used by a computer to do work (I.e. load a number into a register, or add 1 to the value in a register)
HERTZ	A unit of frequency equal to one cycle per second
TRANSISTOR	A device that can transfer or resist electrical current

Measures of Quantity

K	Kilo one thousand
Kb	Kilobyte 1024 bytes 2 to the 10th power	1 page of A4 paper can contain approximately 4200 characters (12 points 6 lines per inch) A 360 K Floppy Disk (5-1/4 inch) = 360,000 bytes or 86 pages
M	Mega one million
Mb	Megabyte 1024 x 1034 bytes = 1,048,576 bytes 2 to the 20th power	1.44 Mb Diskette (3.5 inch) = 1,440,000 bytes = 343 pages 120 Mb Diskette (Imation 3.5 inch)= 120,000,000 bytes = 28,571 pages 250 Mb Iomega Zip disk (3.5 inch) = 250,000,000 bytes = 59,524 pages 650 Mb CDROM disk = 650,000,000 bytes = 154,762 pages
G	Giga = billion = milliard
Gb	Gigabyte 1024 x 1024 x 1024 bytes = 1,073,741,824 bytes 2 to the 30th power	DVD disk = 17,000,000,000 bytes or 4,047,619 pages 120 Gb Hard disk = 120,000,000,000 bytes or 28,571,429 pages
T	Terra = Trillion
Tb	Terabytes 1024 x 1024 x 1024 x 1024 bytes = 1,099,511,627,776 bytes 2 to the 40th power	64 DVD's or 261,788,483 pages
P	Peta = Quadrillion
Pb	Petabytes Quadrillion bytes 1024 x 1024 x 1024 x 1024 x 1024 bytes = 1,125,899,906,842,620 2 to the 50th power	268 billion pageswhen a pack of paper - 5 cm then it is a stack of 26,807,140 km high or 65 times to the moon
Eb	Exabyte1024 x 1024 x 1024 x 1024 x 1024 X 1024 bytes = 1,152,921,504,606,850,000 2 to the 60th power	274,506 billion pages, a stack of 27,450,512,014 km high or 68,000 times to the moon

Measures of Time:

Milli	Millisecond Thousand 1/1,000 of a second
Micro	Microsecond Million 1/1,000,000 of a second
Nano	Nanosecond Billionth - Milliard-th 1/1,000,000,000 of a second
Pico	Picosecond Trillionth 1/1,000,000,000,000 of a second
Fento	Fentosecond Quadrillionth 1/1,000,000,000,000,000 of a second

How Components Are Measured:

CPU Word Size	Bit
Bus Size	Bit
Disk, Tape Capacity	Bytes
Memory	Overall Capacity Bytes
SIMM/DIMM/RIMM	Bytes
Individual Chips	Bits
Transmission Speeds:	CPU Clock Speed - MHz
BUS Speed	MHz
Network Line/Channel	bits per second (bps)
Disk Transfer Rates	Bytes per second
Disk Access Time	Milliseconds
Memory Access Time	Nanoseconds
Machine Cycle Time	Nanoseconds
Instruction Execution time	Nanoseconds
Transistor Switching	Nanosecond, picosecond, fentosecond

Last Updated on 17 September, 2002

For suggestions please mail the editors

Footnotes & References

1.	based on: http://caxton.stockton.edu/nascargo/csis1180
2	to imagine how this measures to real world things go here