> Change of IPL mode is more complex I suppose. > Assuming all current OS'es do start in 31-bit mode and switch to 64-bit > mode in early phase and that feature will be removed - no current OS > will IPL ...unless some patches will be issued for them (supported ones > at least). > > It is even more complicated: let's assume I have two machines: z13 as > backup and z14 as production. Will it be possible to simply re-IPL the > system from the same disk? Or I would have to prepare two flavours of > IPL device, dedicated to each of the machines? > Been there during 9672-z/Series times and I could simply re-IPL same > system on both machines. Both systems: OS/390 and z/OS. I don't know > about other OSes.
z/OS and z/OS Stand-alone Dump have been prepared for a z/Architecture-only machine since z/OS 1.12. z/OS used to run in ESA/390 mode up until the point in IPL where LOADxx was processed, so that a LOADxx parm could be used to determine whether ESA/390 or z/Architecture should be the final mode. And stand-alone dump needed to run in the mode of the system it was dumping. Removing the ESA/390 support was a fair amount of work, especially in stand-alone dump, and I did not want us to have to do that in multiple releases via PTFs, so I did in in z/OS 1.12, long before there was a plan as to when a z/Architecture-only machine would be built. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
