the format of a system file.
System files use four data types: 8-bit characters, 32-bit integers,
-64-bit integers,
+64-bit integers,
and 64-bit floating points, called here @code{char}, @code{int32},
@code{int64}, and
@code{flt64}, respectively. Data is not necessarily aligned on a word
int32 rec_type;
int32 label_count;
-/* @r{Repeated @code{label_cnt} times}. */
+/* @r{Repeated @code{n_label} times}. */
char value[8];
char label_len;
char label[];
@table @code
@item int32 measure;
-The measurement type of the variable:
+The measurement level of the variable:
@table @asis
+@item 0
+Unknown
@item 1
-Nominal Scale
+Nominal
@item 2
-Ordinal Scale
+Ordinal
@item 3
-Continuous Scale
+Scale
@end table
-SPSS sometimes writes a @code{measure} of 0. PSPP interprets this as
-nominal scale.
+An ``unknown'' @code{measure} of 0 means that the variable was created
+in some way that doesn't make the measurement level clear, e.g.@: with
+a @code{COMPUTE} transformation. PSPP sets the measurement level the
+first time it reads the data using the rules documented in
+@ref{Measurement Level,,,pspp, PSPP Users Guide}, so this should
+rarely appear.
@item int32 width;
The width of the display column for the variable in characters.
@table @asis
@item 5
-A set of grouped variables (according to Aapi H@"am@"al@"ainen).
+A named variable set for use in the GUI (according to Aapi
+H@"am@"al@"ainen).
@item 6
Date info, probably related to USE (according to Aapi H@"am@"al@"ainen).