Someone asked me the other day – What is a TB when used in computer terms? TB stands for Terabyte. So, what is a byte?

A byte is the unit of measure of one character of text on a computer [the most common size byte being 8 bits, but it’s apparently not standard]. Another way to say this is a byte is the base unit of measure for how many characters computer storage/memory space can hold. So, a 1 byte drive can hold 1 character of data. Working from 1 byte, the next largest measured capacity is the kilobyte. 1 kilobyte is 1000 bytes [or characters] of data storage space. They could theoretically have a decabyte [10] and an hectobyte [100], but they aren’t typically used as a measure of computer storage capacity. Bytes are based off of the base 10 [metric] system.

The meter is the unit of length in the base 10 system. Some of the more familiar measures of length are:

millimeter [10 to the negative 3rd power = 1/1,000th of a meter]

centimeter [10 to the negative 2nd power = 1/100th of a meter]

decimeter [10 to the negative 1st power = 1/10th of a meter]

meter [10 to the zero power = 1 meter]

decameter [10 to the 1st power = 10 meters]

hectometer [10 to the 2nd power = 100 meters]

kilometer [10 to the 3rd power = 1,000 meters]

So, replace meter with byte and you have the same table:

A byte can be or is made up of bits, but I won’t get into that!

1 byte [10 to the 0 power = 1 character space]

1 kilobyte (KB) [10 to the 3rd power = 1,000 character spaces]

1 megabyte (MB) [10 to the 6th power = 1,000,000 character spaces or 1,000 kilobytes]

1 gigabyte (GB) [10 to the 9th power = 1,000,000,000 character spaces or 1,000 megabytes or 1,000,000 kilobytes]

1 terabyte (TB) [10 to the 12th power = 1,000,000,000,000 character spaces or 1,000 gigabytes or 1,000,000 megabytes or 1,000,000,000 kilobytes]

1 petabyte (PB) [10 to the 15th power = 1,000,000,000,000,000 character spaces or 1,000 terabytes or 1,000,000 gigabytes or 1,000,000,000 megabytes or 1,000,000,000,000 kilobytes]

1 exabyte (EB) [10 to the 18th power = 1,000,000,000,000,000,000 character spaces]

1 zettabyte (ZB) [10 to the 21st power = 1,000,000,000,000,000,000,000 character spaces]

1 yottabyte (YB) [10 to the 24th power = 1,000,000,000,000,000,000,000,000 character spaces]

And one last one for kicks!

1 googol (aka: google – which is a misspelling of googol, but pronounced the same) [10 to the 100th power = 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,

000,000,000,000,000,000,000,000,000,000,000,000,000 character spaces]

If a computer program says that it requires 300MB of storage space to run, that means it needs 300,000,000 bytes or character spaces on the storage device in order to be installed. That is fine if it is installed on a 500GB hard drive because 500GB = 500,000,000,000 bytes [character spaces]. So the 300MB program would take up 300,000,000 / 500,000,000,000, which is 6 times 10 the negative 4th power, which is .0006 amount of the available character spaces.

Now, that is why memory capacity becomes more important than hard drive capacity for computer speed. If you only have 12GB of memory, that is 12,000,000,000 bytes [character spaces]. 300,000,000 / 12,000,000,000 is a larger amount at .025 of the capacity of character spaces available. So, the computer is trying to cram the same amount of bytes [character spaces] into a smaller space of available bytes [character spaces], which slows the computer down.

Computers rarely run programs straight off the hard drive. They usually pull the data that is required to run the program into memory because the memory can communicate more quickly with the processor and other computer components. That is why some programs take a while to load but then run more quickly after they have loaded. As long as there is enough memory, there should be enough space to run everything fairly quickly!

If there is not enough memory, the computer then has to decide what information is more critical and try to pull that data from the hard drive onto the memory. The process may have to repeat several times. It has to clear memory space before it can pull more information off the hard drive. That is also why a computer slows down when it is running multiple programs at the same time. Now it is really filling up all the memory space with a lot of bytes and the computer has to start backlogging processes in order of priority.

Here is a brief description of processor speed that I calculated. 1 GHz is 1,000,000,000 bytes per second. This is because second is usually the standard unit of measure for time. With that known, a 1GB program will run in 1 second. 1,000,000,000 divided by 1,000,000,000 equals 1, and second is the unit of measure for time. It’s like rate times time equal distance [meters] only distance is replaced with bytes [storage character spaces].

Also, program load, run speed or download speed can also be calculated. A connection speed of 1KB/s is transferring data at a rate of 1 kilobyte per second. A 1 kilobyte file takes 1 second to transfer at that rate. Now, a 3MB file at 300KB/s is going to take how long to download? Convert megabytes to kilobytes. 3MB equals 3,000KB. Take the program size [or file size] divided by the rate to get time. 3,000KB / 300KB = 10 seconds for the amount of time for that much data to make the transfer.

That’s a long explanation to what a Terabyte is, but hopefully it makes more sense now. The larger the size hard drive, the more bytes [characters] it can hold. However, that doesn’t mean increased computer performance.

***References:

http://en.wikipedia.org/wiki/Byte

http://en.wikipedia.org/wiki/Terabyte

http://en.wikipedia.org/wiki/Googol