Almost all products on the IBM mainframe has a three letter abbreviation (TLA). In order to make the confusion complete IBM has given all products a synonym TLA used for naming the product components like LOAD modules, message identifiers and BookManager manuals. This tip will give you a comprehensive cross reference between product names and their IBM TLA.
Before looking at the cross reference I will give some insight into the peculiarities of the IBM TLAs. My favourite product DB2 uses DSN as a synonym TLA. How on earth could anyone in their right minds do this. DSN is the abbreviation of Data Set Name and has been it for many many years before DB2 entered the scene. Another curiosity is the synonym abbreviation for PL/I which is IBM. They has a field day at the PL/I development team when they came up with this TLA.
Let us look into the cross reference. It it far from complete but I have tried to cover the most well known products and hope you can use it as a word of reference. And there are lots of exceptions like product name changes and TLA name changes, but the synonym TLA does not change. This constant name changing also increases the confusion.
| Product name | Normal abbreviation | IBM synonym TLA |
| DB2 | DB2 | DSN |
| CICS | CICS | DFH |
| IMS | IMS | DFS |
| TSO | TSO | IKJ |
| ISPF | ISPF | ISP |
| PL/I | PLI | IBM |
| COBOL | COB | IGY |
| REXX | REXX | IRX |
| Language Environment | LE | CEE |
| DFSMS | SMS | DGT |
| HSM | HSM | ARC |
| RACF | RACF | ICH |
| DFSORT | SORT | ICE |
| MQSeries/Websphere MQ | MQ | CSQ |
| QMF | QMF | DSQ |
| SDSF | SDSF | ISF |
| Tivoli | OPC | EQQ |
| JES2/JES3 | JES | IEF |