Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!ames!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!gryphon!oleg From: oleg@gryphon.COM (Oleg Kiselev) Newsgroups: comp.unix.aix Subject: Re: AIX on IBM370 machines Keywords: AIX, IBM, mainframe Message-ID: <20027@gryphon.COM> Date: 18 Sep 89 07:44:19 GMT References: <13676@well.UUCP> Reply-To: oleg@gryphon.COM (Oleg Kiselev) Distribution: comp Organization: HASA Lines: 64 In article <13676@well.UUCP> sebic@well.UUCP (Dave Truckenmiller) writes: >Does anyone out there know if one could run AIX on a mainframe (IBM370) >while also running OSes like MVS, CICS, and TSO? Yes. AIX currently runs as a guest on a VM of its own, in no way interfering with other virtual machines. >If this is possible >is it possible for "files" to be shared between the OS partitions >while they are running? Not quite. Or rather, yes, but there are peculiarities. From AIX, one can go into CP mode of the VM and access files and devices strictly via VM. The access can be interactive or non-interactive. If the former, the system behaves as if you were accessing a pure VM. In the latter case, the output of the VM command can be piped to a UNIX program on AIX side. This means that you can't open a file on a CMS disk from your UNIX program by doing open(), but there is no reason why a driver can not be written to access a CMS or MVS or TSO disk s a raw device and do file access according to that OS's idea of a file system layout. >Also, will AIX work with the existing 3270 >terminals, or does one need to add ASCII terminals for AIX? Yes, you can use a 3270, but there are problems. First, there is a problem with a block mode terminal interacting with an inheretly character stream system. Using vi(1) is possible but hardly pleasant. Some software uses the full-screen block mode 3270 with some amount of grace (there is a modification to curses and terminfo and driver support for that mod to allow full-screen controllable access to the 3270), but there is no editor that would use all of the features of the 3270 and work around all the deficiencies of this (in my opinion) brain-damaged terminal Second, there is a basic flaw in the very concept of VM that presumes that the guest OS is a single-user, single-process system. AIX circumvents this flaw by making AIX site the "single user" and the UNIX system the "single process" on the virtual machine. However, AIX is not capable of allowing more than one console on the VM. So only one 3270 terminal, the "console" from which the AIX site was logged in, can be truly "directly" connected to the site. Other 3270 terminals would need to be attached to other virtual machines. If such "other" VM is running AIX and is on the same TCF cluster, all file access and resource use is transparent between sites and for all intents and purposes, you can say that there are multiple 3270s accessing the system. If these "other" VMs are not AIX or are in another AIX cluster, telnet and rlogin would let the 3270 be connected to the site via BSD-style pseudo terminals (pty). Of course, if you have at least one PS/2 running AIX/TCF, you can hang some 2 dosen or so terminals on it and do all your access to your 370 AIX through a "normal" UNIX style ASCII terminal. >We do however have a client who >wants our U*IX product to "run" on his mainframe. I was just >wondering if we could easily port it to AIX. Most probably yes. AIX is very close to both System V and 4.3 BSD. If you are not doing anything sVr3-like (streams) and have written your code in a more or less portable way, you should have no problems at all. -- "No regrets, no apologies" Ronald Reagan Oleg Kiselev ARPA: lcc.oleg@seas.ucla.edu, oleg@gryphon.COM (213)337-5230 UUCP: [world]!{ucla-se|gryphon}!lcc!oleg