1 byte (1B)  8 binary digits, a byte can have 1 of 256 possible values
1 kilobyte (1KB)  1024 bytes, a side of A4 printed text can be stored in 3 or 4 KB
1 megabyte (1MB)  1024 kilobytes - a 3.5inch floppy disc holds about 1.5 MB. a CD holds about 700MB
1 gigabyte (1GB)  1024 megabytes, a CD stores 0.75GB, and writable DVD holds 4.7GB
1 terabyte (ITB)  1024 gigabytes, this is about the same as 110 commercially produced DVDs
download  to copy information from another computer
upload   to send information to another computer