On Mon, 17 Mar 2003 16:21:43 -0500, Steve Gentry <[EMAIL PROTECTED]> wrote:
>The writer made the comment that : ><snip> > > >Well, IBM (NYSE: IBM - news) mainframes as old as the original System 370, which >debuted in 1970, had >the ability to create what are called virtual machines, which allow one >version of the operating system to keep running while a kind of duplicate >copy running on the same physical machine is upgraded. Once a fix is made >to code, the patched version of the OS can be swapped into place for the >running version, all without taking down the system. > ></snip> > >Further . . . > >"Once a fix is made to the code, the patched version of the OS can be >swapped into place . . . without taking down the system" > >I've been a sys.prog. for about 20 years, 15 of those in VM and I don't >know of any feature that will let a sys prog do this! If so, I've spent a >lot of late nights and weekends upgradeing when I could have done it >during the week. In reality, no you do not have to power the box off, but >you do have to cycle VM or VSE. I'm not sure about z/OS, but since the >author mentions "virtual machines" aka VM, in my opinion he is wrong. Now >don't misunderstand me, I'm for VM getting all the "accurate" press it can >get. However, if some unknowing decision maker takes this and runs with >it, VM could be set up for some bad press. As I understand the article, >he is trying to imply that VM never has to be taken down, cycled, IPL'd, >booted, what ever term you want to use, to bring new OS code in. I should >mentioned one exception that I know of. VSE had/has a mechanism to bring >patched code in. I don't remember the exact process anymore, but it was >used in emergency situations only. I would never apply a list of PTF's to >VSE and bring it on line via this method. VM may have a similar function. >If so I've never used it. Heck, VM hardly ever breaks. (my plug for VM). >But in this case, the method of bring in patched code is not unique to VM. >Sort of off thread. At one site I worked at, me and another sys.prog >convinced the Op. Manager that we had done a "Shadow IPL", i.e, bring new >OS code, more than one module, into use while the machine was still >running. He believed us for about 5 minutes. >Steve G A couple of times I patched a VM system using STCP commands... <grin> john alvord
