| RELCODE | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | Assmbler for UNIVAC I and II |
| SAC | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | Electrodata assembler for Burroughs |
| SOAP I | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | First release of SOAP |
| STAR | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | Burroughs 200/205 assembler |
| SYMBOLIC ASSEMBLY | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | Symbolic assembler for IBM 705 |
| X-1 | ⊕ 1956 | ↓ ↑ ⊕ Excluded from Sammet | ⊕ Symbolic assemblers | ⊕ United States | Experimental Assembler For Univac II |