Re: [MI400] Does as400 use open firmware at IPL?

[Keith Carpenter <carpcon@xxxxxxx>]

IBM used OF in their RS/6000s.  Now that IBM offers basically the same 
machine as i5, p5 and OpenPower (linux) models it's entirely possible 
they share a similar firmware (differences more for marketing/licensing 
reasons).

With the new “Virtualization Engine", it's doubtful the OS would touch 
the hardware boot rom.   AFAIK, the traditional AS/400 boot sequence 
involved loading the microcode (hardware diags), starting the virtual 
machine (MI level), loading and starting OS400.  This might have been 
covered in the Diagnostics Aids manual.

If you interested in how an OS boots, you might look at how Linux loads 
in a LPAR.  I don't know if the iSeries versions of RedHat or Suse are 
available for download, but here's an effort to run Debian in a LPAR.
http://www.adelux.fr/site_adelux/libre/howto/iseriesen


Keith





Steve Richter wrote:
> http://www-128.ibm.com/developerworks/library/pa-spec2.html
>
> "...Open Firmware is software that is used after powering a machine to bring
> the operating system online (most visibly on PowerPC® and SPARC systems).
> ..."
>
> "...OF is "Firmware" in the sense that it is "boot firmware," the code that
> runs in a machine between when power first hits the CPU and when the OS gets
> loaded. ... OF is written in ANSI Forth. ..."
>
> Curious to know how the as400 IPLs. Does it run open firmware?
>
> -Steve
>
>
>
>
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