Subject: Booting from other devices

From: [email-masked] (Markus Illenseer)

Starting loadbsd with option -b ends up in a requestor for the boot-device.
It displays the choice between sdxa, fdxa and cdxa. (Isn't 'a' wrong ?)
(rstxa is missing, too >;-)

 My question: is cdxa what i think it is? CD-ROM ? 
What should the CD contain, whoich flag must be set to make NetBSD boot
from a CD? Does this work - /dev/* cannot be written on CD, the device-nodes
are missing in ISO-9660 Level 2 (w/ or w/o RR)?

-- 
Markus Illenseer

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From: [email-masked] (Michael L. Hitch)

> (rstxa is missing, too >;-)

  Um, the code shows that it should be printing "fd%d sd%d cd%d" - there
isn't any 'a' there to be printed.

  Exactly how would you get a root file system on a tape drive and be able
to do random accesses from it :-)

>  My question: is cdxa what i think it is? CD-ROM ? 

  Yes.

> are missing in ISO-9660 Level 2 (w/ or w/o RR)?

  I would guess that the CD would have to be written with a ffs file system
and a partition table that includes the 'a' partition - unless there is
some other code somewhere that knows enough to mount the root with the
cd9660 filesystem.  I don't remember seeing that anywhere.  Anyway, I don't
think an ffs formatted CD would work anyway - the kernel won't work if
the block size isn't 512 bytes.  If the CD could do 512 byte blocks (I
think some drives are capable of working in 512 byte blocks - I assume
the drive must be doing the buffering & deblocking) and were written with
a ffs partition (and in the Amiga's case, the RDB would also have to be
present to provide the partition information), it might work.

Michael

-- 
Michael L. Hitch			INTERNET:  [email-masked]
Computer Consultant
Office of Systems and Computing Services
Montana State University	Bozeman, MT	USA

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From: [email-masked] (Ty Sarna)

Yes.

> from a CD? Does this work - /dev/* cannot be written on CD, the device-nodes

What do you mean by setting flags? You just enter cdXa.

> are missing in ISO-9660 Level 2 (w/ or w/o RR)?

Rock Ridge disks can have device nodes.

-- 
Ty Sarna                  "Shut up, I'm having a rhetorical conversation!"
[email-masked]                  -Max, _The Producers_

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From: Hubert Feyrer <[email-masked]> "Re: Booting from other devices" (Sep 26, 2:00pm)

> > (rstxa is missing, too >;-)
...
> to do random accesses from it :-)

I don't know *how* to do it, but I know this is possible on e.g. SUNs and HPs.
So, this isn't impossible. Maybe some SUN/HP-guru could enlighten us?

Hubert

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=============== Hubert Feyrer ============================================
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From: [email-masked] (Ty Sarna)

> So, this isn't impossible. Maybe some SUN/HP-guru could enlighten us?

Sun, at least for older versions, had a special "munix" (memory unix)
kernel that used a ramdisk for root, and preloaded the ramdisk from an
image on the tape.

There are some systems with random-access tapes though, which can boot
directly off tape. I think Sequent was one, but my memory is fuzzy.

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From: Alan Bair <[email-masked]>

> So, this isn't impossible. Maybe some SUN/HP-guru could enlighten us?

Typically the way this works is to copy the root image off of tape into the
future swap partition. Then perform a special boot that does all processing in
real memory, no use of the swap space. This "mini-unix" (munix in Sun terms)
is used to setup the other filesystems copying the OS files from the rest of
the tape or other tapes. Then you boot the newly constructed system.

I have never heard of actually running the OS off of tape, though it can be
done with CD-ROM using the same type of swap less execution.

-- 
Alan Bair             		MCTG AMCU DSCS
Motorola, Inc.            	    (Design Software &
Mail Stop OE-320		     Computer Services)
6501 William Cannon Dr. West	(512) 891-2336
Austin, TX  78735-8598          [email-masked]

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From: [email-masked] (Markus Illenseer) "Re: Booting from other devices" (Sep 26, 2:00pm)

On Sep 26,  2:00pm, Michael L. Hitch wrote:
> Subject: Re: Booting from other devices

 Well yes, the code states this, that's true. But it's wrong. You have to type
'sd0' rather than 'sd0a' to boot.

> to do random accesses from it :-)

 Tapeworm? Well, it was just a suggestion...

> the block size isn't 512 bytes.  If the CD could do 512 byte blocks (I

 Hu? 

> present to provide the partition information), it might work.

 If you state 'cd0' fro booting, the kernel should switch over to ISO-9660,
no? I don't believe the kernel really requires FFS! 

 The RDB is another problem which bothered me, too.

-- 
Markus Illenseer

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From: Olaf Seibert <[email-masked]>

> So, this isn't impossible. Maybe some SUN/HP-guru could enlighten us?

I seem to recall (from reading about it) that a common procedure to boostrap
v7 on pdp-11s was to boot from a tape with a carefully prepared file system
on it. The important thing was to arrange it so, that it only needed to be
read in forward direction. I presume it relied on the relevant inodes to be
cached in core. For files it should not be too difficult to arrange, if every
file is read just once.

-Olaf.
--
___ Olaf 'Rhialto' Seibert    [email-masked]     Ooey-Gooey-Fluffy-Barfie
\X/ I'm not weird, I'm differently percepted. D787B44DFC896063 4CBB95A5BD1DAA96

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From: [email-masked] (Markus Illenseer) "Re: Booting from other devices" (Sep 26, 8:12pm)

> Rock Ridge disks can have device nodes.

 Hu? Are you really sure about this? Why don't all those Linux-Distributions
use this? They all use a boot-floppy. I was almost certain that RR doesn't
support device node entries, i guess i have to check again.

 It would be nice to have a bootable NetBSD-(Amiga) CD, i need more
info to do so.

-- 
Markus Illenseer

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From: [email-masked] (Markus Illenseer) "Re: Booting from other devices" (Sep 27, 1:18pm)

On Sep 27,  1:18pm, "Chris G. Demetriou" wrote:
[RR on CD with device nodes]
> >  Hu? Are you really sure about this?
> 
> Yup, it's true.  RR disks can have device nodes.

 Aha? Great! :-) This eases the process. Anyone have mkisofs for NetBSD? 

> > Why don't all those Linux-Distributions
> > use this? They all use a boot-floppy.
> 
> Don't forget, PC's can't boot off of CD-ROM's...

 I am not sure if understand this correctly. There is no way telling the BIOS to
boot from CD rather than from C: ? *Faint memory* Hm, you might even be right,
poor PC-Users :) 

 So they need the Bootfloppy to be able to mount the CD and then start-off the
rest of the system? 

 Anyway, i don't believe Amiga can either. No RDB. And requires CD-driver in ROM.
So we have to deal with a Bootfloppy or at least a 'loadbsd' and 'special.netbsd'
startable from CD. 

 Hm, i could be in need for a new flag in loadbsd: -boot_from_cd_but_don't_use_-b_flag
is that hard to do? 

-- 
Markus Illenseer

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From: [email-masked] (L. Todd Masco)

In article <[email-masked]>,
>the tape or other tapes. Then you boot the newly constructed system.

Actually, munix (at least, SunOS 4.1.1 munix) can run straight out of
memory, from tape, without using the swap partition.  I genned a 4/260 a
week ago doing this... it's tight, but it works.

In general, though, you do load the mini-root to a swap partition.
-- 
L. Todd Masco  | "'War's good business, so give your sons': Oh, I'd rather
[email-masked]  |   have my country die for me." - Jefferson Airplane

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From: [email-masked] (Ty Sarna)

>  Aha? Great! :-) This eases the process. Anyone have mkisofs for NetBSD? 

Yes, 1.0 works fine. 1.01 works if you back out one change, otherwise it
generates disks on which NetBSD can't seem to find the RR information.

> > Don't forget, PC's can't boot off of CD-ROM's...

386BSD-1.0 claims to ;-) ;-)

>  So they need the Bootfloppy to be able to mount the CD and then start-off the

No, you can just boot into AmigaOS, mount the CD, and run loadbsd off of
it. You're only going to do this for installation anyway, since you'll
need a writable root (at a minimum) on HD for real use.

> So we have to deal with a Bootfloppy or at least a 'loadbsd' and 'special.netbsd'

Well, CDTV and CD32 can, obviously, but that's because they have the ISO
filesystem in ROM.  Although, if you're clever you might be able to fit
a RDB on an ISO filesyetem, if there is any free space in the first
RDB_LOCATION_LIMIT blocks...  then the rest of the blocks could be in a
file.  It would be a lot of work, but it might be possible without
breaking the rules.  I'm almost certain that it's possible by bending
the rules a bit, in a way that shouldn't break much.  I don't think
it's worth the effort though. How often are they going to boot the CD to
install?

>  Hm, i could be in need for a new flag in loadbsd: -boot_from_cd_but_don't_use_-b_flag

I don't think that loadbsd needs any changes at all.

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From: Hubert Feyrer <[email-masked]> "Re: Booting from other devices" (Sep 27, 4:58pm)

> support device node entries, i guess i have to check again.

I guess the fact that they use a boot-floppy over a bootable CD is simply the
fact that you (usually...) can't boot a PC off a CD-ROM.

Hubert

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From: [email-masked] (Markus Illenseer) "Re: Booting from other devices" (Sep 28, 10:37am)

> fact that you (usually...) can't boot a PC off a CD-ROM.

 Well, why don't they boot into normal DOS (from drive C:) and mount
the CD and then start Linux off the CD? Why the Floppy? 

 I thought the floppy was necessary because the device node entries
couldn't be written onto the CD and thus had to be moved onto the floppy.

-- 
Markus Illenseer

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From: "Matthias Scheler" <[email-masked]>

Hi Markus,

> the CD and then start Linux off the CD? Why the Floppy? 

Why do they use MS-DOS or Windows ?
Never ask for the reason of anything related to PCs.

> couldn't be written onto the CD and thus had to be moved onto the

Ok, let's go for the booting Amiga NetBSD CD.

-- 
Matthias Scheler
[email-masked]

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From: John Shardlow <[email-masked]>

Hi

> In general, though, you do load the mini-root to a swap partition.

That's right. The Sun machines do a two stage boot for the initial install.

First munix (totally memory resident) which allows you to partition the disk.

Then once you have created the swap partition you can load mini-root into
it which allow you to do the actual installation of root and /usr partitions.

Munix and mini-root are quite different beasts.

John 

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