Subject: RISCOS/ARMlinux dual boot

From: Wookey <[email-masked]>
Date: Mon, 14 Feb 2000 18:16:32 +0000 (GMT)

Is there a recommended way to set up a machine for dual boot?

First I tried putting !Linux in Predesk but I just get a complaint that
it can't get the 2Mb it needs, so I gave up on that and replaced !Boot
with !linux instead so that you get a 1:RISCOS, 2: Linux choice straight
away. This boots ARMLinux fine but if you choose RISCOS it just drops you
to the supervisor prompt - fair enough, but is there a way of getting it
to execute an obey file on exit so that you can on to do a normal desktop
boot? Perhaps a different set-up would achieve a similar effect?

I'd just like to be able to choose which OS to start on boot, but
otherwise have them start up as normal.

On a related note, if you normally start to RISCOS, and run !linux to
boot Linux, is there a mechanism to get shutdown to leave some kind of
pointer around so that it would either restart to RISCOS or restart to
ARMlinux according to parameters given? I can see that this could be
difficult, but it would be nice.

Wookey
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From: Peter Naulls <[email-masked]>
Date: Mon, 14 Feb 2000 21:17:23 +0000

In message <[email-masked]>

> difficult, but it would be nice.

In both cases, you could do what NetBSD does.  That is:

(a) catch a key press in Preboot (Basic program, with INKEY), and then
set a system variable to cause boot sequence to be largely skipped over.
In desktop, if it's set, run !Linux.

(b) BSD sets a value in CMOS - it uses this to alter the
default behaviour of (a).

I suggests taking a look at the BSD bootloader.

Peter

-- 
+---------------------------------------------+-----------------------------+
| Peter Naulls - [email-masked]              |                             |
| http://free.prohosting.com/~chocky/         | Java and JVM Consultant     |
| Java for RISC OS and ARM - [email-masked] | Technical Author            |
| http://free.prohosting.com/~chocky/java/    | Program performance analyst |
+---------------------------------------------+-----------------------------+

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From: Russell King - ARM Linux Admin <[email-masked]>
Date: Mon, 14 Feb 2000 22:12:38 +0000 (GMT)

> Is there a recommended way to set up a machine for dual boot?

Yes, please read the !Help file within !Linux - IIRC it gives information
on exactly how to do this.

> difficult, but it would be nice.

Yes, it's a WIBNI, but not currently possible.  I've thought about allowing
it to write back to the partition some sort of identifier (into the
/boot/boot.map file) to indicate which OS was last selected - there's some
space in the header for this iirc.  However, if you re-run loadmap under
Linux, it will reset it back to the default.  Maybe this is a good thing?

A better choice may be a CMOS RAM location, but that means we have to "pinch"
it.

Ideas?
   _____
  |_____| ------------------------------------------------- ---+---+-
  |   |        Russell King       [email-masked]      --- ---
  | | | |  http://www.arm.linux.org.uk/~rmk/armlinux.html    /  /  |
  | +-+-+                                                     --- -+-
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