Fixed syntax

If a group data object is always the same size (in bytes), it has a fixed syntax. For example, a record that is always 160 bytes has a fixed syntax.

Each component of a fixed group must be fixed. If you break down a fixed group, it ultimately consists of items that are fixed. Each is padded to a fixed size or its minimum and maximum content size are equal. Do not specify the size of a fixed group. The size is automatically calculated based on the size of the group's components.