To give a first impression about the data structure, here follows a simple test file, which contains the header, a label, a couple of scalars, an array, and a short table:
fileform uio form=formatted convert=native version=0.1.1997.11.29 &
date='29.11.1997 21:23:39.835' system=IRIX machine=atlas osrelease=6.3 &
osversion=12161207 hardware=IP32 language=Fortran90 program=uiotst
label testdata n='sample test data field' date='29.11.1997 21:23:39.835'
integer ia f=I3 b=4 n='This is the answer'
42
complex ca f='''('',E13.6,'','',E13.6,'')''' b=8 n='This is a complex answer'
( 0.400000E+01, 0.200000E+01)
real da f=E23.15 b=8 n='precise answer'
0.420000000000000E+02
real answer f=F4.0 b=4 n=answer u=1
42.
real real2d d=(100:103,200:204) f=E13.6 p=4 b=4
0.100000E+01 0.200000E+01 0.300000E+01 0.400000E+01
0.500000E+01 0.600000E+01 0.700000E+01 0.800000E+01
0.900000E+01 0.100000E+02 0.110000E+02 0.120000E+02
0.130000E+02 0.140000E+02 0.150000E+02 0.160000E+02
0.170000E+02 0.180000E+02 0.190000E+02 0.200000E+02
table f77table d=(1:5,1:7) f=1X b=1 n='test table to test the table routines'
integer int1 f=I5 b=4 n='Integer: 1. Spalte'
real real1 f=F5.1 b=4 n='Real: 2. Spalte'
character char1 f=A16 b=16 n='Char: 3. Spalte'
real real2 f=E13.6 b=4 n='Real: 4. Spalte'
integer int2 f=I5 b=4 n='Integer: 5. Spalte'
int1 real1 char1 real2 int2
1 2.0 a 0.100000E+02 1
2 4.0 ab 0.200000E+02 2
3 6.0 abc 0.300000E+02 3
4 8.0 abcd 0.400000E+02 4
5 10.0 abcde 0.500000E+02 5
6 12.0 abcdef 0.600000E+02 6
7 14.0 abcdefg 0.700000E+02 7