411 REFERENCE · Wikibooks
360 Assembly/360 Assemblers
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
IBM Provided
There are two assemblers. The older "Basic Assembly Language" and the "High Level Assembler". There are certain constructs in the macro language as well as some of the newer assembly language instructions which are available only in the High Level Assembler.
Third-Party Assemblers
The ASSEMBH assembler for the Fujitsu BS2000 is essentially the same as IBM's High Level Assembler.
The z390 Assembler provides an open-source assembler and emulation of the 360, 370 and z/System computers.
For more information, check out the pages IBM basic assembly language and IBM High Level Assembler on Wikipedia.