[log in to unmask] wrote: :just make sure that every time you install a patch or a new subsystem to move :the 5.0 LinkEdit back - the 4.0 LinkEdit cannot deal with the 5.0 enhancements :such as shared globals etc.pp. :I would suggest to move the 'old' compilers and linkedit out of PUB.SYS into :another group (i.e. COMPILE.SYS) to make sure your developing environment does :not interfere with the MPE OS environment. :Kindest regards: :Christian Frank, :RCO Ratingen, Network Operating Systems :<[log in to unmask]> - Maybe you could use something like we use here in HP CSY (networking lab - OS lab has a bit different setup to my knowledge), where we have several build environments (like 4.0, 4.5, 5.0 pull/push). Compile/link scripts set up the proper account name to use for includes etc, *and* for compiles and linkedit. Even when the source may be the same for all OS versions, the list of include files, defined types, compilers and linkedit may have tricks that need to be executed bit differently from release to release. For example, here's a list of SYS-accounts on a system that I use for building NS stuff for different OS'es. SYS <<-- the 'real' one SYS22 '2.2' SYS30 '3.0' SYS31 '3.1' SYS40 '4.0' SYS45 '4.5' SYS47 '5.0 pull' - some of the early ones SYS4718 ...later one SYS4720 ...and the final 5.0 pull SYS5002 '5.0 push' SYS5004 ...next version SYS5007 ...next version SYS5010 ...MR'd version Thus the compilers then are as: PASCALXL.PUB.SYS PASCALXL.PUB.SYS22 PASCALXL.PUB.SYS30 PASCALXL.PUB.SYS31 PASCALXL.PUB.SYS40 PASCALXL.PUB.SYS45 PASCALXL.PUB.SYS47 PASCALXL.PUB.SYS4718 PASCALXL.PUB.SYS4720 PASCALXL.PUB.SYS5002 PASCALXL.PUB.SYS5004 PASCALXL.PUB.SYS5007 PASCALXL.PUB.SYS5010 :-) Cheers, Eero Laurila - HP CSY Networking lab, NS services.