The following mainframe REXX facilities are not supported by 
               		MSS: 
               	 
            
 
            	 
             
               		
               - Sequence numbers in the last eight bytes of fixed-length source records are recognized but no checking is done on the order
                  of these numbers. Sequence numbers in variable-length records are not recognized. 
                  		
               
- The TRACE S instruction is syntactically allowed but does not trace the remaining clauses in the exec. The exec is fully syntax
                  checked when it is first loaded. 
                  		
               
- Numeric options entered during interactive debugging are not supported. 
                  		
               
- CICS REXX is not supported. 
                  		
               
- Compiled REXX execs are not supported. 
                  		
               
- APPCMVS, ATTACH, ATTACHMVS, ATTACHPGM, CONSOLE, CPICOMM, ISPEXEC, ISREDIT, LINK, LINKMVS, LINKPGM, and LU62 host command environments
                  are not supported: 
                  		
               
- User-defined host command environments are not supported. 
                  		
               
- The following REXX programming services are not supported: 
                  		  
                   
                     			 
                     - IRXEXCOM - variable access routine 
                        			 
                     
- IRXEXEC - exec processing routine 
                        			 
                     
- IRXHLT - halt condition routine 
                        			 
                     
- IRXIC - trace and execution control routine 
                        			 
                     
- IRXINIT - initialization routine 
                        			 
                     
- IRXLIN - LINESIZE function routine 
                        			 
                     
- IRXRLT - get result routine 
                        			 
                     
- IRXSAY - SAY instruction routine 
                        			 
                     
- IRXSUBCM - maintain entries in the host command environment table 
                        			 
                     
- IRXTERM - termination routine 
                        			 
                     
- IRXTXT - text retrieval routine 
                        			 
                     
 
- Replaceable routines and exits are not supported. 
                  		
               
- DBCS is not supported.