[Novalug] Accessing BIOS

[Bryan J Smith]

Megan had it correct.

PXE is what allows SYSLinux (more specifically, the PXELinux program)
to be loaded.  Yes, this is provided by BOOTP/TFTP, but PXE is
the standard that is _not_ part of the PC BIOS that hooks itself
in to provide this support.  Without PXE, or another approach
(the PC world has had several), there is *NO* netboot capability
(at least not without "helper media").

Hence my analogy to DMI.  It's just one standard, of several, to
provide facilities that are not inherent, differ and, in some cases,
are vendor-specific and not universal.  Fortunately PXE has become
the most common, just like DMI.  Not everything has DMI, just like
not everything has PXE.

--  
Bryan J Smith - mailto:b.j.smith at ieee.org  
http://www.linkedin.com/in/bjsmith
Sent via BlackBerry from T-Mobile  
    

-----Original Message-----
From: James Ewing Cottrell 3rd <JECottrell3 at Comcast.NET>
Date: Fri, 15 Jan 2010 16:52:56 
To: Megan Larko<larkoc at iges.org>
Cc: <novalug at calypso.tux.org>
Subject: Re: [Novalug] Accessing BIOS

BOOTP, and DHCP by extension, supplies a field which the client can 
interpret as a filename and retrieve via TFTP. Sound like PXE?

Perhaps the best example is an X Terminal. The X Terminal BIOS (er  ... 
firmware (Bryan rests his case again)) sends a BOOTP request, and 
downloads the operational code for the terminal.

Many embedded systems use BOOTP to download their executable images to 
run in memory this way, saving the need for a local disk.

JIM

Megan Larko wrote:
> James Ewing Cottrell 3rd wrote:
>> We all do. I am still wondering, however, how PXE differs from any 
>> other BOOTP or DHCP environment.
> 
> Well, I thought it was in the diskless boot (syslinux execution) 
> ability.  DHCP can assign a lease for an IP number (either routable or 
> non-routable).  PXE allows exectution of syslinux.  I don't know if 
> plain DHCP "executes" anything.
> 
> I'm sure Bryan J. Smith will correct me.   Smile.
> 
> megan
>>
>> Or is PXE a specification about what the downloaded program's 
>> environment will be?
>>
>> JIM
>>
>> Megan Larko wrote:
>>> Gee Whiz...I actually like the PXE (pre-execution environment) name; 
>>> it makes sense to be for diskless booting of many node cluster 
>>> systems.   Is that so wrong?
>>>
>>> SMILE!
>>> megan
>>>
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