Something that can be quite confusing is all the talk of bits, bytes, Megabytes, Gigabytes and so on.
These words are measures of the size of a data file or size of the storage space like a hard drive in a computer.
Knowing a little about these sizes can help to understand the capacity of a mobile device to store information.
Some practical examples of how many of these bytes are needed for different purposes is given immediately below.
If you want to know a little bit more of the technical detail see the Bits and Bytes section below.
What do these sizes mean in practical terms?
Here are some common thing that might be stored on a computer along with a typical size in bytes to give a feel for how much storage is needed for different activities on a computer.
Text, Books, Documents
A 1,000 bytes (or one kilobyte) can store 1,000 characters and so a whole A4 page of text and numbers will require about 10-14 kilobytes. (10,000-14,000 bytes)
About 1 Megabyte, or one million characters, is enough for a small paperback book (text only)
Music
About 6 Megabytes could store a single popular song if it uses special compression (squashing) of the file
(Compression will result in lower sound quality)
About 60 Megabytes could store a single uncompressed popular song with high quality; CD quality.
Still Images
One thousand Megabytes or one Gigabyte) will be able to store about 40 images from a modern digital camera (14 Megapixel camera)
About 16 Gigabytes will hold around 700 images from the same digital camera
A mobile phone with 32 Gigabytes memory might be able to store store over 1,000 digital images as the camera in the phone could be around 12 megapixel. (with no video stored)
Video
5 to 10 Gigabytes is needed to store a DVD movie
One Terabyte (one thousand Gigabytes) could store about 100 DVD movies
Video can be further compressed to reduce storage, but like music, the compressed version has reduced quality.
Around 10 compressed movie-length videos could be stored on a 16 Gigabyte memory stick.
(These numbers are for a normal High Definition DVD but there are now multiple newer variations which require more storage for a higher definition picture)
Bits and Bytes
This discussion is a bit technical but is deliberately simplified to try to help understanding.
The numbers below are approximations to give the sense of the issue.
Bits
A bit is the smallest unit of information that a digital device recognises.
It can take a value of 1 or 0 as computers only recognise these two numbers and use what is known as binary arithmetic to do everything that we experience from them.
Computers only use these two numbers, but other numbers are converted so that they can do calculations like decimal arithmetic, for humans.
This 'binary arithmetic' concept is important for computers but can be mostly ignored in the explanation below.
Bytes
Groups of 8 bits make up a byte which can represent decimal numbers from 0 to 255.
Here is what a byte looks like: 0000 1010
[This byte is equivalent to 10 in decimal.]
A byte is roughly equivalent to a single character or number in a document.
Characters such as; A, z, #, 5 or ] can be stored as a single byte.
When we have lots of bytes we use the following prefixes to show the bigger numbers:
- kilo means 1,000
- Mega means 1,000,000 (one million)
- Giga means 1,000,000,000 (one thousand million)
- Tera means 1,000,000,000,000 (one million million)
- Peta means 1,000,000,000,000,000 (one thousand million million)
Bits and Internet Speed
Just to confuse things, the speed of internet connections uses bits per second rather than bytes per second.
The usual measure is in is millions of bits per second or Megabits per second (Mbps)
The reason for this is that internet data is transmitted bit by bit so counting the total bits makes more sense for this purpose.
Because the internet speed is Mbps then a 100 Mbps connection will require 8 seconds to deliver 100 Megabytes.
(each byte needs 8 bits so 100 Megabytes is equivalent to 800 Megabits.
Computer Processor Bit Size
The summary below explains how bit size is just a development feature of computers generally.
The only reason to know about this is that it is important to match software with the bit size of your computer.
When early computers moved to 8 bits (1 byte) it made operation faster and, for technical reasons, more memory could be used.
As computers were further developed, bytes were grouped to give larger 'words'. Computers moved from 8 bit to 16, 32 and now are usually 64 bit. (that is an 8 byte word because 8 bytes x 8 bits per byte gives a total of 64 bits)
The most important thing to remember here is to match your software choices to your computer.
Most software will have a 64 bit version so if your computer is 64 bit then this matches.
An older computer may be 32 bit and requires 32 bit software.
Normally the 64 bit computer can run 32 bit software but it may be slower.
A 32 bit computer cannot run 64 bit software.