Subject: Re: MIPS Kernel size

From: Ralf Baechle <[email-masked]>
Date: Mon, 2 Feb 2004 15:09:25 +0100

On Tue, Jan 27, 2004 at 03:51:31PM +0100, [email-masked] wrote:

> What will be the approximate size for a minimal MIPS kernel?

Btw, the -tiny tree of 2.6 has been booted on a 2MB system.  Supposedly that
was an i386 system so MIPS16 should boot in an even smaller system and a
normal 32-bit MIPS kernel should have enough space to wiggle in 4 megs.

Does anybody on this list actually still care about that small systems?

  Ralf

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From: Karsten Merker <[email-masked]>
Date: Mon, 2 Feb 2004 19:43:25 +0100

> Does anybody on this list actually still care about that small systems?

Depends on what you consider "that small". Kernel size is a large
issue for the Cobalt series due to the firmware limits (although
Peter Hortons attempts at a Cobalt bootloader will hopefully help in
this regard). Embedded stuff and PDAs is another field where 2.6
currently seems to pose a problem.

Regards,
Karsten
-- 
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oder Uebermittlung meiner Daten fuer Werbezwecke oder fuer die Markt- oder
Meinungsforschung.

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From: Ralf Baechle <[email-masked]>
Date: Mon, 2 Feb 2004 19:57:26 +0100

> currently seems to pose a problem.

I really hate that term "embedded" - it's very hard to define.  Anyway,
there's an increasing amount of so-called embedded systems with several
gigabytes of memory and even for much smaller system 2.6 is already
making 2.4 look pale.

The Cobalt case is special; it's firmware could almost be the definition
of the term crap ...

  Ralf

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From: Geert Uytterhoeven <[email-masked]>
Date: Mon, 2 Feb 2004 20:38:18 +0100 (MET)

> gigabytes of memory and even for much smaller system 2.6 is already

Indeed. Today's embedded can easily be larger than desktop/server from only
a few years ago...

Fortunately, system size is still important for some applications. Witness the
existence of a System Size Working Group in the CE Linux Forum. So yes, some
people still care.

> The Cobalt case is special; it's firmware could almost be the definition

Can't you use the firmware to load a second stage booter, which can load larger
kernels?

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email-masked]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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From: Ralf Baechle <[email-masked]>
Date: Mon, 2 Feb 2004 20:46:22 +0100

> existence of a System Size Working Group in the CE Linux Forum. So yes, some

All but one of the new MIPS systems I got in the past years support memory
sizes in the GB range ...

> Can't you use the firmware to load a second stage booter, which can load
> larger kernels?

That would be possible - but would still leave all the other limitations
of the original firmware such as not supporting netboots.  Peter Horten
seem to have worked on something better.

  Ralf

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From: Geert Uytterhoeven <[email-masked]>
Date: Mon, 2 Feb 2004 20:50:38 +0100 (MET)

> seem to have worked on something better.

Unles the second stage booter supports netboots. I don't know anything about
the Cobalt firmware, but just using it to load something like uBoot should be
possible, right?

Gr{oetje,eeting}s,

						Geert

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From: Ralf Baechle <[email-masked]>
Date: Mon, 2 Feb 2004 20:59:37 +0100

> the Cobalt firmware, but just using it to load something like uBoot should be

Oh, it boots everything as long as it's a compress ELF executable named
/vmlinux.gz on a PC-style partitioned disk with an ext2 filesystem
(must be revision 0!) on it's first partition or it uploaded with cu(1)'s
send file command at 115200bps, 8N1.  No luxury, whistles or bells at
all.

  Ralf

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From: Thiemo Seufer <[email-masked]>
Date: Mon, 2 Feb 2004 21:07:42 +0100

Ralf Baechle wrote:
> /vmlinux.gz

AFAIK it also boots such a kernel from a NFS(!) export.

> on a PC-style partitioned disk with an ext2 filesystem

Thiemo

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From: Ralf Baechle <[email-masked]>
Date: Mon, 2 Feb 2004 21:32:37 +0100

> AFAIK it also boots such a kernel from a NFS(!) export.

Well possible - the firmware contains a Linux kernel of approx 2.0.30
vintage, so that would have been easy to arrange.  When I kernel work for
Cobalt however booting from disk and over serial were the only two
available options.

  Ralf

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From: Peter Horton <[email-masked]>
Date: Mon, 2 Feb 2004 22:29:47 +0000

> Can't you use the firmware to load a second stage booter, which can load larger

Yes, but you still have to maintain a old style EXT2 partition just for
the firmware.

Besides, after a while your second stage loader starts to look like a
boot loader anyway, once you've added network booting of large kernels,
kernel command line support and the other things the original firmware
was missing.

P.