This is the boring stuff. Everybody wants to just jump in the car and start driving, just like everyone wants to just flip the switch and compute. But, like cars, there should be a license requirement before you log on so that you know what you’re doing. You should know (1) the size of your computer’s files and (2) the structure that those files are stored in. The first so that you will know how fast you’re filling up your drives, the second so that you can find whatever you’re created.
I apologize in advance, because there’s no way to make this stuff interesting. But it’s necessary. You have to have an idea about the size of your files, graphics, videos, MP3 and other digital items and also the size of the drives and other peripherals required to handle them most efficiently. Whether it’s the amount of RAM on your main board or other computer memory, your hard drive, DVD burner, flash drive or network backup drive, they’re all expressed in the size measurements which follow. (And all of these bits and bytes are stored on your hard drive in a heirarchal file structure, but that’s a separate discussion.) So, like it or not, you have to have at least a relative basic understanding of bits and bytes:
A bit (short for BInary digiT) is the smallest unit of data in a computer. A bit can have a binary value of either 0 or 1. Binary means that there are only two logical (i.e. on/off, true/false) choices. Until the value is actually determined, it can have two states. [To learn about other systems with more than two choices per digit, go to BASE-X.] With respect to the physical storage of bits on a computer’s hard disk drive, the binary value reflects whether the bit is on (magnetic) or off (not magnetic). Click HERE for more explanation. Think of it like this: if you wrap lots of copper wire around a rod, then connect each end of the wire to the two poles of a battery, the rod will be magnetized and pick up iron. When you take one of the wires off of the battery, it’s no longer a magnet. You’ve turned it on and then off. There are only those two choices. That’s binary system (bi = two), and it also demonstrates the relationship between electricity and magnetism, a recurring computer principle. For more about how your computer computes with binary code, click HERE.
[To confuse the issue slightly more, there’s quantum computing, where the values of data can both (i.e 0 and 1) exist together at the same time (“superposition”) and are known as “qubits”. But that’s another entirely separate area. Click on the definitions above if you want to understand this somewhat philosophical data principle.]
A byte is composed of 8 bits. Similar to the bit, the value of a byte is stored on the hard drive as either above or below a designated level of electrical (therefore magnetic) charge in a single capacitor. Half a byte (4 bits) is called a nibble. [Sometimes, the term octet is used for an 8 bit unit instead of a byte.] Also, in many systems, 4 - 8-bit bytes form a 32 bit word (and sometimes a half-word 16 bits long).
A kilobyte is 1024 bytes (Why exactly 1024 bytes? Because binary computers count in twos, so 1024 is the closest power of 2 to 1000 (2 to 10th power). Click HERE for more information about this). A megabyte is approximately 1 million bytes (actually, it’s 1,024 kilobytes or 1,048,576 bytes, see the comparison charts below). Similarly, a gigabyte is 1024 megabytes (1024 megabytes, 1,048,576 kilobytes, 1,073,741,824 bytes); and a terabyte is 1024 gigabytes. A petabyte is 1024 terabytes. An exabyte is 1024 petabytes. And a zetabyte is 1024 exabytes. The largest current unit of measurement for computer data is the yottabyte, which is 1024 zetabytes.
An Mb is not the same as a MiB! As mentioned above, making matters even more confusing, there is terminology distinguishing the above approximations with the exact unit measurements. For example, a a Pebibyte is exactly 2 to the 50th power, or 1,125,899,906,842,624 bytes and a Mebibyte is exactly 2 to the 20th power, or 1,048,576 bytes. A mebibyte is 1024 Kibibytes and precedes the Gibibyte as a unit of data storage measurement. [These exact measurements were introduced by the International Electrotechnical Commission (“IEC”) [see Associations] back in 1998 for those scientific and engineering instances where exact data measurement is required.]