Options for boot program

Giorgos Keramidas keramida at ceid.upatras.gr
Thu Jun 15 10:56:34 UTC 2006

On Thu, 15 Jun 2006 07:02:11 GMT, "gs_stoller at juno.com" <gs_stoller at juno.com> wrote:
> My way of operating is to multi-task almost all the time [...]
> Hence I want the boot program to sound a bell (possibly several
> times with a short interval to wait between successive times, and
> proceed immediately when I respond [and not wait for a set # of bells
> to be sounded]) if it is waiting for input [...]
> I realize that other users of the boot program may want it to
> behave differently than I do.  Consequently, each user should be able
> to tell the boot program how he wants it to behave regarding these
> matters, and other matters that some user may be able to describe [...]
> One way to make the boot program aware of a user's preferences
> is to store these preferences (options) in the boot sector [...]

I apologise in advance if excessive snipping was done above, but I tried
to keep your major points intact.

I don't think it is a good idea to try to cram more features in the
severely limited space the boot0 stage currently has.  The entire boot0
object code should fit in less than 512 bytes (some of that space is
used to store the BIOS-partition table too).  Adding more and more
features every time we want to extend it will quickly make it either
buggy or unusable for the majority of the people who currently use it.

On the other hand, there are other boot managers, which can use more
space and are not as limited.  It may be a good idea to try one of those
and extend it to cover your needs.  A very featureful and nice option is
GRUB, which -AFAIK- currently supports Windows, Linux, FreeBSD, Solaris
and a few other OSes.

Unfortunately, the GRUB port of FreeBSD is i386-only, so if you are
running something else (sparc64 or amd64), it is impossible to use it.

I'd put my own money into porting GRUB to work with all the major
architectures currently supported by FreeBSD.  Then, I would add the
features you like to GRUB, which already includes an extended set of
configuration options and can easily incorporate more.

> I would like to suggest some minor changes to the boot program for
> FreeBSD , mainly in the area of options that the user can set when
> installing it.  Hopefully the space available for the boot program
> will be big enough to allow these changes.  By the way, is there more
> space available (e.g., more sectors on the platter/cylinder) for the
> boot program?

Not much space is available.

> Where can one get the code for the boot?

The source code for the boot0-stage loader is:


> Also, how much space is available for the boot code?

A very small number of bytes.  Forget about this, if you ask me...

- Giorgos

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