The SPARC 10u6 & later miniroot

[Tim Bradshaw]

Does anyone know how this works? This is the thing that can be found
in boot/sparc.miniroot on the install DVD.

This looks like a UFS disk image. So, on a SPARC box I made it
available as a device using lofiadm, used fstyp / fsck to check it
really was a UFS image, and mounted it (r/o). You get what is pretty
clearly a miniroot, except the contents of all the files looks like
gibberish.

My guess is that they may use some kind of auto-uncompressing thing (so
the files are actually compressed somehow), but I don't know how that
works. Can anyone help?

A related question is: is the failsafe boot archive the same image (I
think it's not), and if not, where does it come from (or how is it
made)?

The x86 miniroot is much more straightforward.

Thanks

--tim

(The reason I'm poking about in this stuff is that I want to make sure
I understand the nasty rebuild-the-boot-archive-on-mirrored-root bug.)

[Drazen Kacar]

Tim Bradshaw wrote:

> My guess is that they may use some kind of auto-uncompressing thing (so
> the files are actually compressed somehow), but I don't know how that
> works. Can anyone help?

/boot/solaris/bin/root_archive is the compress/decompress utility. It's a
shell script and the usage is explained in the comments.

You use it to unpack miniroot into some directory where you get the normal
files, then you modify stuff in that directory and finaly pack it again
into the miniroot image.

--
.-. .-. Yes, I am an agent of Satan, but my duties are largely
(_ \ / _) ceremonial.
|
| da...@fly.srk.fer.hr

[Casper H.S. Dik]

Tim Bradshaw <t...@tfeb.org> writes:

>Does anyone know how this works? This is the thing that can be found
>in boot/sparc.miniroot on the install DVD.

>This looks like a UFS disk image. So, on a SPARC box I made it
>available as a device using lofiadm, used fstyp / fsck to check it
>really was a UFS image, and mounted it (r/o). You get what is pretty
>clearly a miniroot, except the contents of all the files looks like
>gibberish.

>My guess is that they may use some kind of auto-uncompressing thing (so
>the files are actually compressed somehow), but I don't know how that
>works. Can anyone help?

All the files are compressed; there's a command called "fiocompress"
and it requires changes to ufs and the uncompress driver "dcfs".

>A related question is: is the failsafe boot archive the same image (I
>think it's not), and if not, where does it come from (or how is it
>made)?

I believe so; typically, a failsafe archive is exactly that file.
It's more than the standard boot archive (kernel only)

>The x86 miniroot is much more straightforward.

grub allows you to uncompress the whole root archive. With
SPARC we can't do that so instead we give compress all the
file individually (except the kernel, ufs, dcfs and everything needed
to load ufs and dcfs)

Casper
--
Expressed in this posting are my opinions. They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.

[Tim Bradshaw]

On 2009-07-03 09:41:38 +0100, Casper H.S. Dik <Caspe...@Sun.COM> said:

> grub allows you to uncompress the whole root archive. With
> SPARC we can't do that so instead we give compress all the
> file individually (except the kernel, ufs, dcfs and everything needed
> to load ufs and dcfs)

Thanks! Based on the other followup I'd found fiocompress and dcfs,
but hadn't worked out the underlying reason for it all. So thanks to
both followups.

--tim