A hex editor (or binary file editor or byte editor ) is a type of
computer program that allows a user to manipulate the fundamental binary (0 /
1, zero / one) data that makes up computer files. Note that computer files can
be very small (just a name, with no content) to very large (content spanning
multiple hard disks). A typical computer file occupies multiple areas on the
platter(s) of a disk drive, whose contents are put together to form the file.
For more details see the wikipedia:Hex_editor.
One of the best Hex Editors, and probably the most user friendly is
XVI32. The
name XVI32 is derived from XVI, the roman notation for the number 16.
A fairly comprehensive comparison chart can be found on
[wikipedia:Comparison_of_hex_editors wikipedia]
The most common uses for a hex editor are:
http://www.chmaas.handshake.de/delphi/freeware/xvi32/xvi32.htm
http://en.wikipedia.org/wiki/Comparison_of_hex_editors