Bootstrap Loader vs Firmware - was Re: [plug] How does "signing" work?

[Arie Hol]

At 05:25 PM 20-06-2003 +0800, you wrote:

>When the "general computer" boots, its firmware will be in charge of
>bootstrapping the system. At the appropriate time (e.g. after doing
>hardware checks), it will load some (first-stage) executable objects
>from an input device for which the device driver is in the firmware's
>limited repertoire (it could be read-only or read-write, local or
>networked, etc.). Those objects are then executed and they may load
>device drivers to allow reading of a second-stage executable such as a
>UNIX kernel (which would itself have the ability to reading the rest of
>theOS via your hard disk's filesystem).
>
>If look back to the loading of the first-stage executable, it is
>essentially a process whereby the ("immutable") firmware loads
>executable objects into RAM and executes them. The firmware can
>obviously decide not to load, or to load but not execute, those objects.
>It would generally do so on the basis of validity -- does the format
>match the current hardware, for instance. It is easy to imagine that
>some 'checksum' system could also be employed: scan the objects and make
>sure they appear to be intact.  The next step could be to perform
>cryptographic analysis of the objects to make sure that they were signed
>by a signer that is known to the firmware (presumably the firmware
>manufacturer and its business partners of the season). To answer your
>question: since the CPU and firmware reside on the same board and are
>thus "inseparable" (you could take the CPU out of the board but then you
>wouldn't have anywhere to run the CPU), and the CPU relies on the
>firmware to load the operating system, the firmware has control over
>what operating system is loaded.
>

You have lost me with the above explanation - are you sure you got it right ?

The above seems to be overly complex and a little off target .

Firmware - usually relates to ROM embedded software in a specific device ??

BIOS - Basic Input Output System

Bootstrap Loader - goto :
http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?bootstrap+loader

Firmware - goto : http://forum.firmware-flash.com/portal.php

Could somebody enlighten me please ?

Regards Arie

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For the concert of life, nobody has a program.

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