Header Block
The header block contains metadata for use by file readers to identify the type,
                version and format of the file. This is a mandatory block. The keywords that are
                used in this block are:
            | Parameter | Type | Description | 
|---|---|---|
| FILE_TYPE | quoted_string | The only legal value is 'gbs'. | 
| FILE_VERSION | quoted_string | The only legal value is  '1'. | 
| FILE_FORMAT | quoted_string | The only legal value is 'ASCII'. | 
The following is an example of a HEADER
                block:
        $-----------------------------------------------------------------HEADER
[HEADER]
FILE_TYPE     = 'gbs'
FILE_VERSION  = '1'
FILE_FORMAT   = 'ASCII'