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Guy Malachi

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Binary Powers of 10

. Bytes Bits . Deviation from 10^x
1 bit =
1 byte =
1 kilobyte =
1 megabyte =
1 gigabyte =
1 terabyte =
1 petabyte =
1 exabyte =
1 zettabyte =
1 yottabyte =
1 xonabyte =
1 wekabyte =
1 vundabyte =
.125 byte. =
1 byte. =
1,024 bytes =
1,048,576 bytes =
1,073,741,824 bytes =
1,099,511,627,776 bytes =
1,125,899,906,842,624 bytes =
1,152,921,504,606,846,976 bytes =
1,180,591,620,717,411,303,424 bytes =
1,208,925,819,614,629,174,706,176 bytes =
1,237,940,039,285,380,274,899,124,224 bytes =
1,267,650,600,228,229,401,496,703,205,376 bytes =
1,298,074,214,633,706,907,132,624,082,305,024 bytes =
1 bit.
8 bits
8,192 bits
8,388,608 bits
8,589,934,592 bits
8,796,093,022,208 bits
9,007,199,254,740,992 bits
9,223,372,036,854,775,808 bits
9,444,732,965,739,290,427,392 bits
9,671,406,556,917,033,397,649,408 bits
9,903,520,314,283,042,199,192,993,792 bits
10,141,204,801,825,835,211,973,625,643,008 bits
10,384,593,717,069,655,257,060,992,658,440,192 bits


. Bytes 2^X Bits
1 bit =
1 byte =
1 kilobyte =
1 megabyte =
1 gigabyte =
1 terabyte =
1 petabyte =
1 exabyte =
1 zettabyte =
1 yottabyte =
1 xonabyte =
1 wekabyte =
1 vundabyte =
.125 byte. =
1 byte. =
1024 bytes =
1048576 bytes =
1073741,824 bytes =
1099511627776 bytes =
1125899906842624 bytes =
1152921504606846976 bytes =
1180591620717411303424 bytes =
1208925819614629174706176 bytes =
1237940039285380274899124224 bytes =
1267650600228229401496703205376 bytes =
1298074214633706907132624082305024 bytes =


1 bit.
8 bits
8192 bits
8388608 bits
8589934592 bits
8796093022208 bits
9007199254740992 bits
9223372036854775808 bits
9444732965739290427392 bits
9671406556917033397649408 bits
9903520314283042199192993792 bits
10141204801825835211973625643008 bits
10384593717069655257060992658440192 bits

Some interesting facts about what these various-sized bytes can store:

* 1 bit: a binary decision
* 1 byte: a character
* 5 Megabytes: The complete works of Shakespeare
* 2 Gigabytes: 20 meters of shelved books
* 10 Terabytes: The printed collection of the US Library of Congress
* 200 Petabytes: All printed material
* 5 Exabytes: All words ever spoken by human beings

Etymology of Units by PC Hariharan
1.Kilo Greek khilioi = 1000
2.Mega Greek megas = great, e.g., Alexandros Megos
3.Giga Latin gigas = giant
4.Tera Greek teras = monster
5.Peta Greek pente = five, fifth prefix, peNta - N = peta
6.Exa Greek hex = six, sixth prefix, Hexa - H = exa Remember, in standard French,
the initial H is silent, so they would pronounce Hexa as Exa.
It is far easier to call it Exa for everyone's sake, right?
7.Zetta almost homonymic with Greek Zeta, but last letter of the Latin alphabet
8.Yotta almost homonymic with Greek iota, but penultimate letter of the Latin alphabet.

The first prefix is number-derived; second, third, and fourth are based on mythology. Fifth and sixth are supposed to be just that: fifth and sixth. But, with the seventh, another fork has been taken. The General Conference of Weights and Measures (CGMP, from the French; they have been headquartered, since 1874, in Sevres on the outskirts of Paris) has now decided to name the prefixes, starting with the seventh, with the letters of the Latin alphabet, but starting from the end. Now, that makes it all clear! Remember, both according to CGMP and SI, the prefixes refer to powers of 10. Mega is 10**6, exactly 1,000,000, kilo is exactly 1000, not 1024.

With thanks to Duke Ionescu and PC Hariharan for the information contained in the above tables.


Powers of Ten - SI Prefixes
The following tables of prefixes show how to use terms like Gigabytes and Nanoseconds.
The prefix is placed on the front of words to imply a multiple of millions or billions,
or to show a division by (negative powers of ten) a number, as in microsecond.
These prefixes are used with metric measurements. They are also called SI prefixes,
because the metric units are known as the SI Units, where SI means Systeme Internationale.

Powers of 10 - SI Prefixes
prefixletterpower of 10multiplierUS English words
Greater than one - a multiple
kiloK31,000one thousand
megaM61,000,000one million
gigaG91,000,000,000one billion
teraT121,000,000,000,000one trillion
petaP151,000,000,000,000,000 one quadrillion
exaE181,000,000,000,000,000,000 one quintillion
zetta Z211,000,000,000,000,000,000,000one sextillion
yotta Y241,000,000,000,000,000,000,000,000one septillion
Less than one - a fraction
millim-31/1,000one thousandth
microµ *-61/1,000,000one millionth
nanon-91/1,000,000,000one billionth
picop-121/1,000,000,000,000 one trillionth
femtof-151/1,000,000,000,000,000 one quadrillionth
attoa-181/1,000,000,000,000,000,000 one quintillionth
zecto z-211/1,000,000,000,000,000,000,000 one sextillionth
yocto y-241/1,000,000,000,000,000,000,000,000 one septillionth
* note: the letter for micro is the Greek letter 'mu'.
One picosecond is 0.0000000000001 second, or 10-12 second.
(Some say "pie-co", some say "pee-co.")
A terawatt is 1,000,000,000,000 watts of energy.
166 Megahertz means 166 million cycles per second.

Information in the above table courtesy John Bagwell


The Peta-Principle
Jim Binder

Since shortly after the French Revolution of 1789, scientists--and eventually computer scientists--have found it convenient to refer to large quantities of various units of measure with verbal prefixes and letter symbols. Thus kilo- (symbol K) and mega- (M) stand for 10**3 and 10**6, thousands and millions. After World War II, this pair of terms was extended, three zeroes at a time, to giga- (G) and tera- (T), standing for 10**9 and 10**12, billions and trillions (usage here and below is American). In 1975, the world arbiter of the metric system, the General Conference of Weights and Measures (CGPM), based at Sevres near Paris, agreed to add two more terms to the ascending series: peta- (P) and exa- (E) for 10**15 and 10**18, quadrillions and quintillions.

The creation of these newest terms is interesting. The older prefixes, kilo-, mega-, giga-, and tera-, are generally understood to be derived from the ancient Greek words for "thousand," "large," "giant," and "monster," respectively. But peta- departs from the traditional pattern to the extent that there is no Greek (or any other) word to explain it in its present form.

Considering the context, however, (preceding exa-) it is the Greek prefix for "five," penta-, minus the letter "n." The reduction of five letters to four makes it similar in this respect to the existing prefixes. On the other hand, exa- has been reduced to three letters by dropping the "h" from hexa-, the Greek prefix for "six," possibly because the "h" would be silent in standard French.

According to a CGPM report, prefixes meaning "five" and "six" are used because 10**15 and 10**18 are fifth and sixth in the ascending series 10**3, 10**6, 10**9, and 10**12.

(If tera- for 10**12 were taken to mean the Greek prefix for "four," te(t)ra-, minus the second letter "t," that would be an additional reason for its being followed by pe(n)ta- as the prefix for "five." However, the acceptance of tera- as derived from "teras," the Greek word for "monster," seems to be universal.)

The use of Greek words for magnitudes through 10**12 turns out to be awkward in the late twentieth century, since it is difficult to extend the series easily. (After all, what could be bigger than giants and monsters?) Yet it would be even more awkward to throw away the established size-words and start from scratch. Therefore, a backward switch in midstream from a Greek-conceptual to the original Greek-numerical basis (using kilo- for "thousand") is announced as the "expedient" thing to do, simultaneously preserving tradition and leaving the way open to further expansion.

Since 1975, though, and so quietly that current editions of the Encyclopedia Brittanica and World Almanac do not recognize their advent, prefixes with corresponding symbols have materialized for 10**21 and 10**24: zetta- (Z) and yotta- (Y), denoting sextillions and septillions. With these it is easy to see yet another change of direction. While still disyllabic, the names are now semi-artificial (echoing Greek zeta and iota) and symbol-driven, and the series is now based on the Latin alphabet, starting with the last letter and moving backwards, with a long way to go before reaching A. Could this be the last terminological contortion?

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