What are ISO and BS standard?

ISO is the International Standard Organization. It is essentially a federation of national standards bodies from around 150 different countries.
Established in 1947, it is non-governmental organization, with a mission broadly to promote the development of standardization with the objective of facilitating international trade. ISO standards are of course prefixed with 'ISO' (eg: ISO 9000).
BSI is the British Standards Institute. This is the oldest standards body in the world, stemming from a meeting of various industrial institutes in 1901. It alone currently publishes over 20, 00 standards and has operations in over 100 countries. The prefix for its standards is BS (e.g.: BS7799).