Doesn't sound very accidental... :-) Odd. 'run' in /usr/sys on my V6 machine (not that I use that, mind) says: chdir ken cc -c -O *.c ar r ../lib1 rm *.o chdir ../dmr cc -c -O *.c ar r ../lib2 rm *.o which should regenerate them - sort of. I suspect you really meant 'doing sh run creates a lib1 and lib2, but then I get errors from the ld phase with missing symbols'. Yes? If so, the thing is that the V6 linker won't pull in an object module from a library unless a global in it satisfies an already existing (i.e. in the linking process) undefined global. (I don't know if this is true of later linkers; never used 'em.) In other words, when loading a multi-module system, the module with 'main' has to be first, and then the rest in an order such that each one holds a previously-undefined symbol. So the order of the object modules you'll get in lib? from the above, if you precede them with 'rm lib?', is probably not the right order. (The above shell script assumes they already exist, with the modules in the right order, so the above just replaces them with the newly compiled versions...) Here's the ordering in lib1: main.o alloc.o iget.o prf.o rdwri.o slp.o subr.o text.o trap.o sig.o sysent.o clock.o fio.o malloc.o nami.o pipe.o sys1.o sys2.o sys3.o sys4.o Other orders would work too (e.g. you could move sys?.o up just after sysent.o and it should work). My lib2 is somewhat odd, so I hesitate to list it, but since most modules in dmr are pulled in from entries in c.c, almost any order will work, I think. Noel