No, he said it's not emulation or a VM. Something is doing some translation. The language isn't the point...
-----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Mike Schwab Sent: Thursday, August 7, 2025 1:27 PM To: [email protected] Subject: Re: z/OS PCDOS Its coded in GCC. On Thu, Aug 7, 2025 at 12:12 PM Phil Smith III <[email protected]> wrote: > 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 > -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- 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
