Data types
This page describes common binary data types used by Factorio, and most modern day computer applications, internally.
Endianness
All data stored in computers are stored in single, small unit of data called a "byte". Larger units of data are split into multiple bytes. The order in which sequential bytes are assembled together to form a larger unit of data is referred to as it's "endianess". All data saved locally by Factorio is stored in "little"-endian format (because Intel favored little endian processors in the ancient times). All data transferred over the network by Factorio is done in "big"-endian format (the standard for network stuffs, so much so that it's often refered to as "network"-endian). (Please correct any of this if I'm wrong!!) For more information about endianness, please see the Wikipedia entry.