STAR23.COM
A slightly tinier version.

While working with os2man to reduce the starfield to 24 bytes, I looked through
the opcodes to see if there were any convenient byte values that could be
reused.  I noticed that the 41h which represents "inc cx" could be a reasonable
substitute port value for the random number generator.  So I changed the
"in al,40h" to "in al,41h", and changed the destination address of the main
loop to land on the second byte of the port read instead of the next
instruction.  This made it possible to remove the explicit "inc cx" (which
fortunately came immediately before the jump) at the end of the loop and save
a byte.  I don't remember the exact reason why he stayed with the 24 byte
version.  It is possible that he preferred the original look, or that I may
have made an error in the version I sent to him.

With this modification, the starfield looks slightly different.  Most
noticeable to me is that there are none of the bright yellow and fast stars
that a value of 14 would create.  There are fewer stars, and not as many are
getting eaten up at the beginning.  I considered this a lucky side effect, but
it's subjective, so I suggest watching both versions.

-bigcheese