So what is translating the x86 opcodes to Z opcodes? -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Paul Edwards Sent: Tuesday, August 5, 2025 9:07 PM To: [email protected] Subject: Re: z/OS PCDOS
On Tue, 5 Aug 2025 18:08:37 -0400, Phil Smith III <[email protected]> wrote: >This is...interesting, but what is the goal? Or is it just an interest >project? (Nothing wrong with that!) > >Another "interest project": Way back in 2000, Adam Thornton fired up Linux >under VM/ESA on a P/390. In Linux, he ran Bochs. In Bochs, he ran Windows. In >Windows, he ran Exchange. > >Well, maybe "ran" isn't the right word: more like "crawled". But it DID come >up. Eventually. On modern hardware, might even be tolerable! I just realized something - you might have the wrong idea of what z/OS PCDOS is. This is not emulation. It runs applications natively on z/Arch. ie full speed. The applications are not MVS executables though. They are z/PDOS-generic executables. I do happen to use the MVS load module format though. But that's not very important because I have my own loader, so could have used a different format. And indeed, I intend to use PE/COFF format for z/OS Windows. But once the executable is loaded, regardless of format, it is directly executed. There is no emulation. There isn't even a VM (which also means that if there are any bugs in your application, it can crash z/OS PCDOS, ie the EXEC PGM=BIOS will get a S0C4 or whatever). The lack of VM means I don't need privilege. ie any MVS end user can install this software and have an EBCDIC FAT32 system running .exe files at full z/Arch speed. With long filenames too (although you can't see that in the "dir" display currently, because it has been implemented in a crude manner to focus on important technical things). BFN. Paul. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
