amount of boot data read using BIOS;

NTDEV
1

Does anybody know how much data is read using BIOS (before boot drivers kick in) during -

  1. boot?
  2. resume from hibernation?

in Win 7 ?

Thanks.

2

Why not boot Windows over the network using the capability of some network
adapters? Then you can monitor with WireShark or another utility to see how
much data is being transferred in various phases. You could also try using
a bus analyzer for the hard drive and see how much is transferred. Make
sure you set up Windbg on the booting system so you can see when the
transition from BIOS to drivers occurs.

If you have an active MSDN subscription you could post in one of the
monitored Microsoft newsgroups to ask this question and maybe they will
answer if you post gets sent to them. You have to set up a special email
address in MSDN for it to be flagged.

wrote in message news:xxxxx@ntdev…
> Does anybody know how much data is read using BIOS (before boot drivers
> kick in) during -
>
> 1. boot?
> 2. resume from hibernation?
>
> in Win 7 ?
>
> Thanks.
>
>

3

> Does anybody know how much data is read using BIOS (before boot drivers kick in)

By the time " boot drivers kick in" kernel must be already up and running - although boot drivers are loaded before the kernel in order to avoid load-order circular dependency, their entry points are invoked only after kernel has been initialized. One of the very first things that kernel does is initializing HAL, so that HAL image must be already in RAM before kernel’s entry point is invoked.

Therefore, images of kernel, HAL and boot drivers have to be loaded into RAM before ntoskrnl.exe’s entry point is invoked…

Anton Bassov

4

Add one more to the system hive of the registry is loaded after the kernel
and hal to identify the boot drivers. look at
windows\sysystem32\config\system

–
Don Burn (MVP, Windows DKD)
Windows Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr

wrote in message news:xxxxx@ntdev…
>> Does anybody know how much data is read using BIOS (before boot drivers
>> kick in)
>
> By the time " boot drivers kick in" kernel must be already up and
> running - although boot drivers are loaded before the kernel in order to
> avoid load-order circular dependency, their entry points are invoked only
> after kernel has been initialized. One of the very first things that
> kernel does is initializing HAL, so that HAL image must be already in RAM
> before kernel’s entry point is invoked.
>
> Therefore, images of kernel, HAL and boot drivers have to be loaded into
> RAM before ntoskrnl.exe’s entry point is invoked…
>
>
> Anton Bassov
>
>
> Information from ESET NOD32 Antivirus, version of virus
> signature database 4236 (20090712)
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>

Information from ESET NOD32 Antivirus, version of virus signature database 4236 (20090712)

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

5

I don’t have the exact amount of data… I lost that statistic apparently. I *did* have it.

But, I can tell you two things:

  1. It was waaay more than I guessed. Waaaay more;
  2. It’s mostly read in little bitty chunks;

Peter
OSR

6

@Don:

>Add one more to the system hive of the registry is loaded after the kernel and hal to identify the boot drivers. look at windows\sysystem32\config\system

Hi Don, can you please elaborate on this? I looked at this file and it seems to be a binary.

@Peter:
do you remember if it was in hundreds of mega bytes during boot?

7

> Therefore, images of kernel, HAL and boot drivers have to be loaded into RAM before ntoskrnl.exe’s

…and also .NLS tables and the SYSTEM registry.

–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com

8

You could load a copy of the OS into a virtual machine, connect a kernel
debugger to the virtual com port and break on OS start. I know Virtual PC
shows up as a process in task manager, and you can select the column that
shows total I/O read bytes.

Jan

Does anybody know how much data is read using BIOS (before
boot drivers kick in) during -

  1. boot?
  2. resume from hibernation?

in Win 7 ?

9

> …and also .NLS tables and the SYSTEM registry.

I mentioned kernel and HAL just because the OP seems to misunderstand the term “boot driver” - judging from the way he presented his question, he thought that,apart from being loaded before the kernel, boot drivers start their actual operations before kernel’s entry point is invoked…

Anton Bassov