http://www.bsp-gmbh.com/turnkey/ http://www.bsp-gmbh.com/turnkey/ "The MVS Tur(n)key system is a package of freely available parts of the MVS 3.8J Operating Sy

http://www.bsp-gmbh.com/turnkey/ http://www.bsp-gmbh.com/turnkey/ "The MVS Tur(n)key system is a package of freely available parts of the MVS 3.8J Operating System. The Tur(n)key System does not (to the best of my knowledge) contain any copyrighted or licenced software by IBM or any other company. Especially, the MVS 3.8 Operating System is not OS/390, nor z/OS, or any other such thing. The provided hardware emulator (Hercules) may perfectly run these operating systems, but you would need to obtain them, and a licence, yourself. Also keep in mind, please, that CICS, RACF, DB2, ISPF etc are all licenced program products and as such are not available in the Turnkey distribution." It uses Hercules emulator: https://en.wikipedia.org/wiki/Hercules_(emulator) https://en.wikipedia.org/wiki/Hercules_(emulator) See there: "Operating systems which may legally be run, without license costs, on Hercules" MVS is: https://en.wikipedia.org/wiki/MVS https://en.wikipedia.org/wiki/MVS "Multiple Virtual Storage" "Developer IBM" "Initial release 1974" "MVS releases up to 3.8j (24-bit, released in 1981) were freely available and it is now possible to run the MVS 3.8j release in mainframe emulators for free.[2]" "MVS originally supported 24-bit addressing (i.e., up to 16 MB). As the underlying hardware progressed, it supported 31-bit (XA and ESA; up to 2048 MB) and now (as z/OS) 64-bit addressing. The most significant motives for the rapid upgrade to 31-bit addressing were the growth of large transaction-processing networks, mostly controlled by CICS, which ran in a single address space—and the DB2 relational database management system needed more than 8 MB of application address space to run efficiently." "The system is typically used in business and banking, and applications are often written in COBOL. COBOL programs were traditionally used with transaction processing systems like IMS and CICS. For a program running in CICS, special EXEC CICS statements are inserted in the COBOL source code. A preprocessor (translator) replaces those EXEC CICS statements with the appropriate COBOL code to call CICS before the program is compiled — not altogether unlike SQL used to call DB2." "MVS/ESA: MVS Enterprise System Architecture. Version of MVS, first introduced as MVS/SP Version 3 in February 1988. Replaced by/renamed as OS/390 late 1995 and subsequently as z/OS." That is necessary information to understand the comment: https://mobile.twitter.com/mainframed767/status/1258018826823729154 https://mobile.twitter.com/mainframed767/status/125801882682... "Bull. Shit. Theres no TCP stack. Theres no cics, no DB2, no ims." What's certain is that, using just that, one can't run all the "real life" sources that typically depend on CICS or DB2. But also see icedchai's message: https://news.ycombinator.com/item?id=23091687 https://news.ycombinator.com/item?id=23091687 Also, if somebody would think it's easy to hack that using more common tools and on more common platforms: "The native character encoding scheme of MVS and its peripherals is EBCDIC" and not ASCII.