Mainframe Express Assembler Option
- Includes IBM mainframe high level language compatible macro assembler, linker, and emulator for seamless execution of COBOL and mainframe assembler applications on Windows PC.
- http://www.microfocus.com/products/mfeee/

Hello, World program
- MVS JCL (Assembly 370)
- http://www2.latech.edu/~acm/helloworld/asm370.html

NIH Computer Center - Using Assembler Language
- Inhouse doc for NIH, but also contains general assembler programming tips.
- http://datacenter.cit.nih.gov/assem/

The Assembler Connection
- at SimoTime site. Provides examples of 370 assembler coding techniques, instruction set, utilities.
- http://www.simotime.com/sim4lib1.htm#ASMConnect

Assembly Language: CS-310
- Text for the class 'IBM Mainframe Assembly Language Programming: CS310', by Dr. Laurence Leff at Western Illinois University.
- http://www.wiu.edu/users/mflll/cs310/head.html

Tachyon 390 Cross Assembler
- Now you can develop and maintain 370/390 assembler programs from your workstation! With the Tachyon Operating System you can test 370/390 Programs On Your Workstation!
- http://tachyonsoft.com/

Assembler for the mainframe
- Basic routines in High Level Assembler Language.
- http://www.sysprog.net/hlasm.html

Dave's unofficial HLASM web page
- Tips and Frequently Asked questions about IBM's High Level Assembler (HLASM) and S/390 Assembler programming
- http://www.planetmvs.com/hlasm/index.html

Systems/Asm
- Dignus' HLASM compatible assembler product for the IBM mainframe. It's available as a native assembler for OS/390 and z/OS, or as a cross-assembler hosted on Windows, AIX, Solaris, FreeBSD, Linux and Linux/390.
- http://www.dignus.com/

Cole Software's XDC
- The most comprehensive and flexible product available for the debugging of Assembler language programs which execute in the OS/390 (MVS) operating system environments on IBM (and compatible) mainframes.
- http://www.colesoft.com/