Start Here

This site will help you install DOS/360, an early IBM 360 mainframe operating system, on a personal computer using the Hercules 390 mainframe emulation software package. You will gain an understanding of what a systems programmer went through to install DOS/360: decisions, compromises, and working within the limitations of the then-current hardware.

At the end of the installation, you'll have a functioning DOS/360 installation with compilers for the languages IBM provided with DOS/360.

Hercules 390 configuration files, DOS/360 startup card decks, and the Job Control Language card decks needed to install DOS/360 are available in a ZIP download from this site. Links are provided, sometimes to other sites, to download the three emulated tape files containing the DOS/360 and POWER II distribution materials from IBM. This site mirrors all downloads; if the external sites go dark, you can still complete this procedure.

IBM did not copyright much of the software for DOS/360, nor did they subject it to restrictive license agreements, so you can run DOS/360 without concern about license violations.

This web site is organized into five sections:

  1. This section, "Start Here," provides a DOS/360 glossary, links to documentation sources and sites, copyright information, and credits.

  2. About DOS/360, which provides background information about DOS/360 and includes notes for non-DOS/360 users.

  3. The DOS/360 Distribution describes the available DOS/360 distribution materials and summarizes the installation process.

  4. Installation Instructions contains step-by-step installation instructions.

  5. Using DOS/360 includes instructions for normal operation of DOS/360 and a section on the Sort/Merge utility included with DOS/360.

There is no formal support program associated with the procedures or files used here. H390-DOSVS@groups.io, the successor to the Yahoo group H390-DOSVS, is the best place to ask questions. As of mid-2021, there is not a lot of history on H390-DOSVS@groups.io. All files from the retired Yahoo group are in a single zip file, and message content is also saved in a single zip file.

This site does not provide detailed instructions for installation nor general use of Hercules 390; such information is generally available on the Internet. Use "Hercules 390" as a search engine keyword.

Nor does this site provide detailed instructions for the normal operation and use of DOS/360, as such would be a rewrite of existing documentation in tutorial form. Installation instructions are detailed, and with luck and effort you'll acquire the needed operating skills in the course of the installation.

If you do not have experience using an IBM mainframe, you'll find this an uphill trip. Personal computers are quite different and, realistically, quite a bit more capable in many respects than the mainframes that were common 40-50 years ago. The About DOS/360 section includes some information that might help you get through the process.

The configuration files etc. are set up for use on Windows-based computer systems; Linux users will need to be aware of this. Hercules does not seem to care whether text file records are delimited by CR-LF or NL, so it should not be necessary to convert the line endings just to run the scripts and submit the JCL files.