Random Post: DMR posts dws.s from pdp-7 Unix to net.unix-wizards

December 8, 1984 Dennis Ritchie posted the following:
I happened to dredge up an old notebook and found a listing
of the PDP-7 version of dsw.  Because several people have approached
me recently about reviving a version of PDP-7 Unix as a sort of
paleontological exhibit, and because the subject has been discussed
here, I thought people might be interested in seeing the code.
I first considered net.sources, but decided not to carry whimsy too far.                Dennis Ritchie
1) The assembler has Knuth-style temporary labels but no literals.
2) The name of the current directory was evidently ".."
3) Formatting is faithfully reproduced.
4) "sys save" makes a core image.
" dsw
   lac djmp
   dac .-1
   oas cla
   tad d1
   dac t1
   sys open; dd; 0
   lac d2
   sys read; dir; 8
   sys exit
   lac dir
   jmp 1b
   isz t1
   jmp 1b
   lac d1
   sys write; dir+1; 4
   lac d1
   sys write; o12; 1
   sys save
   sys unlink; dir+1
   sys exit
d1: 1
d2: 2
o12: 012
t1: 0
djmp: jmp do
dd: 056056; 040040; 040040; 040040
dir: .=.+8