A segment defines additional database storage characteristics . A segment must map to a single file. A segment can be mapped by only one region.
GT.M uses a segment to define a physical file and access method for the database stored in that file.
A segment-name:
Must begin with an alphabetic character
Can include alphanumerics, dollar signs ($), and underscores ( _ )
Can have from one to 16 characters
GDE automatically converts segment names to uppercase. GDE uses DEFAULT for the default segment name.