@table @code
@item char rec_type[4];
-Record type code, set to @samp{$FL2}.
+Record type code, set to @samp{$FL2}, that is, either @code{24 46 4c
+32} if the file uses an ASCII-based character encoding, or @code{5b c6
+d3 f2} if the file uses an EBCDIC-based character encoding.
@item char prod_name[60];
Product identification string. This always begins with the characters
@end multitable
@end quotation
+A few system files have been observed in the wild with invalid
+@code{write} fields, in particular with value 0. Readers should
+probably treat invalid @code{print} or @code{write} fields as some
+default format.
+
@node Value Labels Records
@section Value Labels Records
been actually observed in system files:
@table @asis
+@item 1
+EBCDIC.
+
@item 2
7-bit ASCII.
The following additional values are known to be defined:
@table @asis
-@item 1
-EBCDIC.
-
@item 3
8-bit ``ASCII''.
Other Windows code page numbers are known to be generally valid.
-Old versions of SPSS always wrote value 2 in this field, regardless of
-the encoding in use. Newer versions also write the character encoding
-as a string (see @ref{Character Encoding Record}).
+Old versions of SPSS for Unix and Windows always wrote value 2 in this
+field, regardless of the encoding in use. Newer versions also write
+the character encoding as a string (see @ref{Character Encoding
+Record}).
@end table
@node Machine Floating-Point Info Record
@itemize @bullet
@item
-The set's name (an identifier that begins with @samp{$}).
+The set's name (an identifier that begins with @samp{$}), in mixed
+upper and lower case.
@item
An equals sign (@samp{=}).
A space.
@item
-The names of the variables in the set, each separated from the
-previous by a single space.
+The short names of the variables in the set, converted to lowercase,
+each separated from the previous by a single space.
@item
A line feed (byte 0x0a).
The total number of bytes in @code{encoding}.
@item char encoding[];
-The name of the character encoding. Normally this will be an official IANA characterset name or alias.
+The name of the character encoding. Normally this will be an official
+IANA character set name or alias.
See @url{http://www.iana.org/assignments/character-sets}.
+Character set names are not case-sensitive, but SPSS appears to write
+them in all-uppercase.
@end table
This record is not present in files generated by older software. See