The byte is the smallest unit of computer storage and represents:
Computer storage capacity is measured in bytes.
In today’s large-capacity servers, gigabyte is more often used.
It implements the first concept of buffer as processing data bit by bit would be really slow. Computer are even going now further processing data at the word size (16/32/64)
Accessing an individual byte frequently requires reading or writing a word at once
You must use the binary notation for the computer resource (memory, disk)
Decimal | Binary | ||||||
---|---|---|---|---|---|---|---|
Value | Si | Value | IEC | JEDEC | |||
1000 | k | kilo- | 1024 | Ki | kibi- | K | kilo- |
10002 | M | mega- | 10242 | Mi | mebi- | M | mega- |
10003 | G | giga- | 10243 | Gi | gibi- | G | giga- |
10004 | T | tera- | 10244 | Ti | tebi- | ||
10005 | P | peta- | 10245 | Pi | pebi- | ||
10006 | E | exa- | 10246 | Ei | exbi- | ||
10007 | Z | zetta- | 10247 | Zi | zebi- | ||
10008 | Y | yotta- | 10248 | Yi | yobi- |
Because a byte is just a binary number (of a maximum of length 8), all byte operations are binary operation.
A byte is also an integer between:
A byte is just a binary number of length 8
//parseInt(x, base)
let byteString = '10101101';
let byteInt = parseInt('10101101', 2);
console.log(byteInt)
A byte is a decimal integer between:
In Javascript:
let toByteStringFormat = function (byteInt) {
let byteString = byteInt.toString(2); // to string base 2
let byteStringWithLeadingZero = String(byteString).padStart(8, '0')
return byteStringWithLeadingZero;
}
console.log(' 0: '+toByteStringFormat(0));
console.log('100: '+toByteStringFormat(100));
console.log('255: '+toByteStringFormat(255));
Byte to hexadecimal means generally to go to integer before converting to the hexadecimal base (16)
In Javascript:
let byteStringToHexadecimal = function(byteString){
let byteInt = parseInt(byteString,2); // Byte is a number of base 2, we parse the string in base 2
return byteInt.toString(16).toUpperCase(); // Hexadecimal is a number of base 16
}
console.log('00000000 ( 0): '+byteStringToHexadecimal('00000000'));
console.log('01100100 (100): '+byteStringToHexadecimal('01100100'));
console.log('11111111 (255): '+byteStringToHexadecimal('11111111'));
All the conversion in a table where the binary column contains the byte.
A byte array is an array of byte.
let byteArrayToLong = function(/*byte[]*/byteArray) {
let value = 0;
for ( let i = byteArray.length - 1; i >= 0; i--) {
value = (value * 256) + byteArray[i];
}
return value;
};
let longToByteArray = function(/*long*/long) {
let byteArray = [0, 0, 0, 0, 0, 0, 0, 0];
for ( let index = 0; index < byteArray.length; index ++ ) {
var byte = long & 0xff;
byteArray [ index ] = byte;
long = (long - byte) / 256 ;
}
return byteArray;
};
The maximum decimal by number of Byte (N) is: <MATH> 2^{N*8} </MATH>
Calculate it:
1 Kilobyte = 103 = 1000 bytes
1 Megabyte = 106 = 1,000,000 bytes
1 Gigabyte = 109 = 1,000,000,000 bytes
1 Terabyte = 1012 = 1,000,000,000,000 bytes
1 Petabyte = 1015 = 1,000,000,000,000,000 bytes
1 Exabyte = 1018 = 1,000,000,000,000,000,000 bytes
1 Zetabyte = 1021 = 1,000,000,000,000,000,000,000 bytes
1 Yottabyte = 1024 = 1,000,000,000,000,000,000,000,000 bytes
1 million seconds = 11.57 days
1 billion seconds = 31.6 years
1 trillion seconds = 31,688 years
1 million inches = 15.7 miles
1 trillion inches = 15,700,000 miles (30 round trips to the moon)
$1 million = < $ .01 for every person in U.S.
$1 billion = $ 3.64 for every person is U.S.
$1 trillion = $ 3,636 for every person in U.S.