no interaction in xterm, but it works in a cygwin shell

[Andreas Seidl <seidlcw at gmx dot net>]

I'm using a Lisp-based computer algebra system called REDUCE. Basically 
it is started by a call of the form:

#!/usr/bin/bash -v
/cygdrive/c/devred/lisp/psl/win32/psl/bpsl -td 16000000 -f 
'C:\devred\lisp\psl\win32\red\reduce.img'

The -v option is for printing the executed commands on the screen. The 
second line calls the Lisp (bpsl.exe) with the memory size (16Mb) and an 
image file (reduce.img). The binary bpsl.exe was compiled under Windows.

In a Cygwin shell, i can have an interactive session without problems, e.g.:

----- start -----
seidl@Bellarmin /cygdrive/d
$ reduce
#!/usr/bin/bash -v
# Run Windows PSL REDUCE.
/cygdrive/c/devred/lisp/psl/win32/psl/bpsl -td 16000000 -f 
'C:\devred\lisp\psl\w
in32\red\reduce.img'
Loading image file :C:\devred\lisp\psl\win32\red\reduce.img

REDUCE Development Version, 10-Dec-03 ...

1: factorial 40;

815915283247897734345611269596115894272000000000

2: factorial 50;

30414093201713378043612608166064768844377641568960512000000000000

3: quit;

Quitting

seidl@Bellarmin /cygdrive/d
$
------ end -----

Now, if I do the same in an xterm, the following happens: There is no 
output on the screen from REDUCE. But I can enter line by line:

factorial 40;
factorial 50;
quit;

As soon as the quit; is entered, all the missing output is flushed to 
the screen, see this screenshot of an xterm session:

----- start -----
seidl@Bellarmin ~
$ reduce
#!/usr/bin/bash -v
# Run Windows PSL REDUCE.
/cygdrive/c/devred/lisp/psl/win32/psl/bpsl -td 16000000 -f 
'C:\devred\lisp\psl\w
in32\red\reduce.img'
factorial 40;
factorial 50;
quit;
Loading image file :C:\devred\lisp\psl\win32\red\reduce.img

REDUCE Development Version, 10-Dec-03 ...

1:
815915283247897734345611269596115894272000000000

2:
30414093201713378043612608166064768844377641568960512000000000000

3:
Quitting

seidl@Bellarmin ~
$
----- end -----

So my question is: Can somebody explain this behaviour, is there a 
solution? (E.g. the command line version of Maple works nicely both in 
xterm and a Cygwin shell.)

Ciao,
Andreas.
--
http://www.fmi.uni-passau.de/~seidl