The five new primitive numeric types are:

• ubyte, an unsigned 1-byte integer
• ushort, an unsigned 2-byte integer
• uint, an unsigned 4-byte integer
• int64, a signed 8-byte integer
• uint64, an unsigned 8-byte integer

Before using these types, consider how the values will be accessed in a language without support for unsigned integers. The uint64 type is especially problematical in this respect.

2008 Unidata NetCDF Workshop for Developers and Data Providers > Using Groups and the New NetCDF-4 Atomic Types