Gentoo Archives: gentoo-mips

From: Kumba <kumba@g.o>
To: gentoo-mips@l.g.o
Subject: Re: [gentoo-mips] Question - Kumba LiveCD RC6
Date: Tue, 23 Jan 2007 02:15:32
In Reply to: Re: [gentoo-mips] Question - Kumba LiveCD RC6 by Mike Martin
1 Mike Martin wrote:
2 > I recently downloaded and attempted to boot an Octane with this disk. It
3 > died mounting the root partition:
4 >
5 > mount: Mounting /newroot/dev/loop0 on /newroot/mnt/livecd failed:
6 > Invalid argument
7 >
8 > Not sure what happened. I assume I burnt the disk correctly else it
9 > wouldn't have made it that far. Any suggestions?
10 >
11 > MikeM
14 It's really hard to say. I tested it on all of my systems before uploading, and
15 with the Octane, this means an external drive (funny enough, an O2 CD drive
16 jammed into a Sun 411 case). And that booted fine on both my Octane and Indy.
18 "Invalid Argument" from mount could mean a wide array of things (yay for Unix's
19 legacy of non-descriptive, ambiguous errors). The process that occurs on an SGI
20 bootcd for us is a rather complex one:
22 1. arcload boots from the DVh partition of the CD
23 (yes, these CDs have partitions)
24 2. arcload finds and boots a kernel
25 3. kernel loads, and executes /init in an embedded initramfs file linked
26 into the kernel
27 4. /init does some prep work, and launches `getdvhoff` to scan the CD
28 for the offset of the next partition (where / lives), and passes a
29 number representing this offset back to `losetup`.
30 5. losetup uses this number to "point" /dev/loop0 at this offset, which
31 effectively makes /dev/loop0 a block device with data on it.
32 6. mount tries to mount /dev/loop0 and pivot_root into the real Gentoo
33 filesystem.
36 Quite likely, step #5 might've failed somewheres along the line. The offset has
37 to be exact to the bit, so maybe something got whacked in the burn and the
38 detected offset is invalid. Hard to say without more information. Thus, when
39 it got to step #6, boom.
41 I'd try re-burning the disk at a slower speed, use only CD-R's of decent quality
42 (TDK, Memorex, Sony, Ricoh/Ritek, etc,.. brands), and use cdrecord (or whatever
43 license-unencumbered version is out there. stupid license wars). A few people
44 reported getting it to work with a windows burn tool, but we have little data on
45 that, thus why cdrecord is the suggested tool.
47 Mostly, you were able to read the kernel into memory, which is ~8MB. It's
48 possible the disc you burned was good enough to get those 8MB off to boot the
49 kernel, but when it went looking for the meat, it got denied and pwned.
53 --Kumba
55 --
56 Gentoo/MIPS Team Lead
58 "Such is oft the course of deeds that move the wheels of the world: small hands
59 do them because they must, while the eyes of the great are elsewhere." --Elrond
60 --
61 gentoo-mips@g.o mailing list


Subject Author
Re: [gentoo-mips] Question - Kumba LiveCD RC6 Mike Martin <mikemartin@×××××.ca>