Mailing List Archive: Special /etc/fstab entries

Special /etc/fstab entries

Oct 23, 2004, 11:20 AM

Post #1 of 9 (349 views)

The original /etc/fstab had two special entries for "fake" devices
/dev/ROOT and /dev/BOOT.
I still use the /dev/ROOT one (renamed /dev/root), and it catches my
root partition at startup.
However, /dev/BOOT never seems to exist, and I have to comment it out.
This raises two
questions in my mind.

1) I keep updating my system to new things, and from time to time use
a different root "/"
partition. Not being partiularaly an organized person, I
sometimes forget which partition
I'm using right now, and the /dev/root nomenclature hides this
both in /etc/fstab and in
the output of the 'df' command. Is there a quick way to figure
out which device it's on?
Just using "ls -lad /dev/root" produces the unreadable
lr-xr-xr-x 1 root root 34 Oct 23 08:11 /dev/root ->
scsi/host1/bus0/target1/lun0/part1
which I can usually figure out after some minutes of poking
around, but forget by next
month when I get curious again. This time it represents
/dev/sda1, but last time it was
/dev/sde1, before I removed a bunch of non-working and/or smaller
scsi devices. So
I'm looking for a quick way, which I will endeavor not to forget. :o)

2) What is /dev/boot or /dev/BOOT supposed to represent, and how
would a kernel know
which actual device it should point to? When it works, what do
people use it for?

++ kevin

--
Go back to the top: I almost always top-post
Kevin O'Gorman, PhD

--
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Re: Special /etc/fstab entries [ In reply to ]

res0r9lm at tampadsl

Oct 23, 2004, 11:45 AM

Post #2 of 9 (342 views)

Permalink

Kevin O'Gorman wrote:

>The original /etc/fstab had two special entries for "fake" devices
>/dev/ROOT and /dev/BOOT.
>I still use the /dev/ROOT one (renamed /dev/root), and it catches my
>root partition at startup.
>However, /dev/BOOT never seems to exist, and I have to comment it out.
>This raises two
>questions in my mind.
>
>1) I keep updating my system to new things, and from time to time use
>a different root "/"
> partition. Not being partiularaly an organized person, I
>sometimes forget which partition
> I'm using right now, and the /dev/root nomenclature hides this
>both in /etc/fstab and in
> the output of the 'df' command. Is there a quick way to figure
>out which device it's on?
> Just using "ls -lad /dev/root" produces the unreadable
> lr-xr-xr-x 1 root root 34 Oct 23 08:11 /dev/root ->
>scsi/host1/bus0/target1/lun0/part1
> which I can usually figure out after some minutes of poking
>around, but forget by next
> month when I get curious again. This time it represents
>/dev/sda1, but last time it was
> /dev/sde1, before I removed a bunch of non-working and/or smaller
>scsi devices. So
> I'm looking for a quick way, which I will endeavor not to forget. :o)
>
>2) What is /dev/boot or /dev/BOOT supposed to represent, and how
>would a kernel know
> which actual device it should point to? When it works, what do
>people use it for?
>
>++ kevin
>
>
>
BOOT and ROOT should be replaced by what ever drives you use for / and
/boot I think /dev/ROOT and /dev/BOOT were in fstab as a hint so if you
already have entries for these partition you can just remove the
/dev/ROOT and /dev/BOOT

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Re: Special /etc/fstab entries [ In reply to ]

kogorman at gmail

Oct 23, 2004, 1:21 PM

Post #3 of 9 (345 views)

Permalink

Well, the odd thing is that after booting, /dev/root is actually what's being
used, as shown by the 'df' output (in part):
/dev/ROOT 19538240 11193236 8345004 58% /

I could well be having a senior moment. It could be that I created this entry
in /dev, and have forgotten. The business of getting gentoo up on this box
was chaotic and stressful for a variety of reasons, som not related to Linux
or gentoo. I could have created that entry to satisfy /etc/fstab, I suppose,
particularly because IIRC devfs didn't get configured by default and I was
having trouble completing the boot process. But maybe that's not it --
if devfs wasn't working, there's no way I would have set it up using that
long pathname, because at that point I would not have know what it was.

Anyway, what to gentoo users usually see from df(1) after booting, as
relates to boot and root?

++ kevin

On Sat, 23 Oct 2004 14:45:52 -0400, Ralph <res0r9lm@tampadsl.net> wrote:
> Kevin O'Gorman wrote:
>
>
>
> >The original /etc/fstab had two special entries for "fake" devices
> >/dev/ROOT and /dev/BOOT.
> >I still use the /dev/ROOT one (renamed /dev/root), and it catches my
> >root partition at startup.
> >However, /dev/BOOT never seems to exist, and I have to comment it out.
> >This raises two
> >questions in my mind.
> >
> >1) I keep updating my system to new things, and from time to time use
> >a different root "/"
> > partition. Not being partiularaly an organized person, I
> >sometimes forget which partition
> > I'm using right now, and the /dev/root nomenclature hides this
> >both in /etc/fstab and in
> > the output of the 'df' command. Is there a quick way to figure
> >out which device it's on?
> > Just using "ls -lad /dev/root" produces the unreadable
> > lr-xr-xr-x 1 root root 34 Oct 23 08:11 /dev/root ->
> >scsi/host1/bus0/target1/lun0/part1
> > which I can usually figure out after some minutes of poking
> >around, but forget by next
> > month when I get curious again. This time it represents
> >/dev/sda1, but last time it was
> > /dev/sde1, before I removed a bunch of non-working and/or smaller
> >scsi devices. So
> > I'm looking for a quick way, which I will endeavor not to forget. :o)
> >
> >2) What is /dev/boot or /dev/BOOT supposed to represent, and how
> >would a kernel know
> > which actual device it should point to? When it works, what do
> >people use it for?
> >
> >++ kevin
> >
> >
> >
> BOOT and ROOT should be replaced by what ever drives you use for / and
> /boot I think /dev/ROOT and /dev/BOOT were in fstab as a hint so if you
> already have entries for these partition you can just remove the
> /dev/ROOT and /dev/BOOT
>
> --
> gentoo-user@gentoo.org mailing list
>
>

--
Go back to the top: I almost always top-post
Kevin O'Gorman, PhD

--
gentoo-user@gentoo.org mailing list

Re: Special /etc/fstab entries [ In reply to ]

res0r9lm at tampadsl

Oct 23, 2004, 4:07 PM

Post #4 of 9 (338 views)

Permalink

Kevin O'Gorman wrote:

>Well, the odd thing is that after booting, /dev/root is actually what's being
>used, as shown by the 'df' output (in part):
> /dev/ROOT 19538240 11193236 8345004 58% /
>
>I could well be having a senior moment. It could be that I created this entry
>in /dev, and have forgotten. The business of getting gentoo up on this box
>was chaotic and stressful for a variety of reasons, som not related to Linux
>or gentoo. I could have created that entry to satisfy /etc/fstab, I suppose,
>particularly because IIRC devfs didn't get configured by default and I was
>having trouble completing the boot process. But maybe that's not it --
>if devfs wasn't working, there's no way I would have set it up using that
>long pathname, because at that point I would not have know what it was.
>
>Anyway, what to gentoo users usually see from df(1) after booting, as
>relates to boot and root?
>
>++ kevin
>
>
>On Sat, 23 Oct 2004 14:45:52 -0400, Ralph <res0r9lm@tampadsl.net> wrote:
>
>
>>Kevin O'Gorman wrote:
>>
>>
>>
>>
>>
>>>The original /etc/fstab had two special entries for "fake" devices
>>>/dev/ROOT and /dev/BOOT.
>>>I still use the /dev/ROOT one (renamed /dev/root), and it catches my
>>>root partition at startup.
>>>However, /dev/BOOT never seems to exist, and I have to comment it out.
>>>This raises two
>>>questions in my mind.
>>>
>>>1) I keep updating my system to new things, and from time to time use
>>>a different root "/"
>>> partition. Not being partiularaly an organized person, I
>>>sometimes forget which partition
>>> I'm using right now, and the /dev/root nomenclature hides this
>>>both in /etc/fstab and in
>>> the output of the 'df' command. Is there a quick way to figure
>>>out which device it's on?
>>> Just using "ls -lad /dev/root" produces the unreadable
>>> lr-xr-xr-x 1 root root 34 Oct 23 08:11 /dev/root ->
>>>scsi/host1/bus0/target1/lun0/part1
>>> which I can usually figure out after some minutes of poking
>>>around, but forget by next
>>> month when I get curious again. This time it represents
>>>/dev/sda1, but last time it was
>>> /dev/sde1, before I removed a bunch of non-working and/or smaller
>>>scsi devices. So
>>> I'm looking for a quick way, which I will endeavor not to forget. :o)
>>>
>>>2) What is /dev/boot or /dev/BOOT supposed to represent, and how
>>>would a kernel know
>>> which actual device it should point to? When it works, what do
>>>people use it for?
>>>
>>>++ kevin
>>>
>>>
>>>
>>>
>>>
>>BOOT and ROOT should be replaced by what ever drives you use for / and
>>/boot I think /dev/ROOT and /dev/BOOT were in fstab as a hint so if you
>>already have entries for these partition you can just remove the
>>/dev/ROOT and /dev/BOOT
>>
>>--
>>gentoo-user@gentoo.org mailing list
>>
>>
>>
>>
>
>
>
df -h

Filesystem Size Used Avail Use% Mounted on
/dev/hda3 27G 17G 9.7G 63% /
none 378M 0 378M 0% /dev/shm
/dev/hda1 99M 35M 60M 37% /boot

mount

/dev/hda3 on / type reiser4 (rw,noatime)
none on /proc type proc (rw)
none on /sys type sysfs (rw)
none on /dev type ramfs (rw)
none on /dev/pts type devpts (rw)
none on /dev/shm type tmpfs (rw)
none on /proc/bus/usb type usbfs (rw)
/dev/hda1 on /boot type ext2 (rw,noatime)

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Re: Special /etc/fstab entries [ In reply to ]

harley7 at cogeco

Oct 24, 2004, 10:26 AM

Post #5 of 9 (345 views)

Permalink

On 13:21 Sat 23 Oct , Kevin O'Gorman wrote:
> Well, the odd thing is that after booting, /dev/root is actually what's being
> used, as shown by the 'df' output (in part):
> /dev/ROOT 19538240 11193236 8345004 58% /
>
> I could well be having a senior moment. It could be that I created this entry
> in /dev, and have forgotten. The business of getting gentoo up on this box
> was chaotic and stressful for a variety of reasons, som not related to Linux
> or gentoo. I could have created that entry to satisfy /etc/fstab, I suppose,
> particularly because IIRC devfs didn't get configured by default and I was
> having trouble completing the boot process. But maybe that's not it --
> if devfs wasn't working, there's no way I would have set it up using that
> long pathname, because at that point I would not have know what it was.

Just a WAG on my part. The kernel knows about the / partition at boot because
it is passed this information from lilo (or grub). That's probably how devfs
can create a /dev/root symlink that points to the proper partition. The /boot
partition (if you have one) needs the actual partition to be mounted because
the kernel can't guess where you want that, or any other partition for that
matter.

BTW, I have a /dev/root and don't have a reference to it in fstab or anywhere
in /etc/devfsd.conf. I guess it just does that on it's own.

Bill

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Re: Special /etc/fstab entries [ In reply to ]

ti.liame at email

Oct 24, 2004, 10:29 AM

Post #6 of 9 (342 views)

Permalink

On Sunday 24 October 2004 19:26, Bill Davidson wrote:
> On 13:21 Sat 23 Oct , Kevin O'Gorman wrote:
> > Well, the odd thing is that after booting, /dev/root is actually
> > what's being used, as shown by the 'df' output (in part):
> > /dev/ROOT 19538240 11193236 8345004 58% /
> >
> > I could well be having a senior moment. It could be that I created
> > this entry in /dev, and have forgotten. The business of getting
> > gentoo up on this box was chaotic and stressful for a variety of
> > reasons, som not related to Linux or gentoo. I could have created
> > that entry to satisfy /etc/fstab, I suppose, particularly because
> > IIRC devfs didn't get configured by default and I was having
> > trouble completing the boot process. But maybe that's not it -- if
> > devfs wasn't working, there's no way I would have set it up using
> > that long pathname, because at that point I would not have know
> > what it was.
>
> Just a WAG on my part. The kernel knows about the / partition at boot
> because it is passed this information from lilo (or grub). That's
> probably how devfs can create a /dev/root symlink that points to the
> proper partition. The /boot partition (if you have one) needs the
> actual partition to be mounted because the kernel can't guess where
> you want that, or any other partition for that matter.
>
> BTW, I have a /dev/root and don't have a reference to it in fstab or
> anywhere in /etc/devfsd.conf. I guess it just does that on it's own.
>
> Bill
>
> --

I bet you get the culprit!

[19:12] [sko@slowdown:~]$ ls -l /dev/root
lr-xr-xr-x 1 root root 4 Oct 24 17:26 /dev/root -> rd/0

In my /etc/lilo.conf I boot this entry:

image=/boot/kernel-2.6.9
label=269
append="root=/dev/ram0 real_root=/dev/hda2 init=/linuxrc
splash=verbose"
initrd=/boot/initrd-2.6.9
vga=0x317

They _must_ be related, don't they?

If you have genkernel installed see:
#cat /usr/bin/genkernel | tail -n 40
and discover where my append line came from...

Ciao
Francesco

--
Linux Version 2.6.9, Compiled #1 Sat Oct 23 15:39:21 CEST 2004
One 665MHz AMD Duron Processor, 768M RAM, 1302.52 Bogomips Total
slowdown

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Re: Re: Special /etc/fstab entries [ In reply to ]

res0r9lm at tampadsl

Oct 24, 2004, 2:54 PM

Post #7 of 9 (344 views)

Permalink

Francesco Talamona wrote:

>On Sunday 24 October 2004 19:26, Bill Davidson wrote:
>
>
>>On 13:21 Sat 23 Oct , Kevin O'Gorman wrote:
>>
>>
>>>Well, the odd thing is that after booting, /dev/root is actually
>>>what's being used, as shown by the 'df' output (in part):
>>> /dev/ROOT 19538240 11193236 8345004 58% /
>>>
>>>I could well be having a senior moment. It could be that I created
>>>this entry in /dev, and have forgotten. The business of getting
>>>gentoo up on this box was chaotic and stressful for a variety of
>>>reasons, som not related to Linux or gentoo. I could have created
>>>that entry to satisfy /etc/fstab, I suppose, particularly because
>>>IIRC devfs didn't get configured by default and I was having
>>>trouble completing the boot process. But maybe that's not it -- if
>>>devfs wasn't working, there's no way I would have set it up using
>>>that long pathname, because at that point I would not have know
>>>what it was.
>>>
>>>
>>Just a WAG on my part. The kernel knows about the / partition at boot
>>because it is passed this information from lilo (or grub). That's
>>probably how devfs can create a /dev/root symlink that points to the
>>proper partition. The /boot partition (if you have one) needs the
>>actual partition to be mounted because the kernel can't guess where
>>you want that, or any other partition for that matter.
>>
>>BTW, I have a /dev/root and don't have a reference to it in fstab or
>>anywhere in /etc/devfsd.conf. I guess it just does that on it's own.
>>
>>Bill
>>
>>--
>>
>>
>
>I bet you get the culprit!
>
>[19:12] [sko@slowdown:~]$ ls -l /dev/root
>lr-xr-xr-x 1 root root 4 Oct 24 17:26 /dev/root -> rd/0
>
>In my /etc/lilo.conf I boot this entry:
>
>image=/boot/kernel-2.6.9
> label=269
> append="root=/dev/ram0 real_root=/dev/hda2 init=/linuxrc
>splash=verbose"
> initrd=/boot/initrd-2.6.9
> vga=0x317
>
>They _must_ be related, don't they?
>
>If you have genkernel installed see:
>#cat /usr/bin/genkernel | tail -n 40
>and discover where my append line came from...
>
>Ciao
> Francesco
>
>
>
I don't have /dev/root. I do use genkernel but I'm using gensplash so
I'm not using the initrd and my kernel append part is a little different
for that reason but yes if your using root=/dev/ram0 that has to be
where it's coming from

title Gentoo
root (hd0,0)
kernel (hd0,0)/boot/kernel-2.6.8-ck7 root=/dev/hda3
video=vesafb:ywrap,pmipal,1024x768-32@85 \ splash=silent,theme:emergence
init=/linuxrc
initrd (hd0,0)/boot/fbsplash-emergence-1024x768

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Re: Re: Special /etc/fstab entries [ In reply to ]

nick at computernick

Oct 24, 2004, 3:46 PM

Post #8 of 9 (339 views)

Permalink

Ralph wrote:

> Francesco Talamona wrote:
>
>> On Sunday 24 October 2004 19:26, Bill Davidson wrote:
>>
>>
>>> On 13:21 Sat 23 Oct , Kevin O'Gorman wrote:
>>>
>>>
>>>> Well, the odd thing is that after booting, /dev/root is actually
>>>> what's being used, as shown by the 'df' output (in part):
>>>> /dev/ROOT 19538240 11193236 8345004 58% /
>>>>
>>>> I could well be having a senior moment. It could be that I created
>>>> this entry in /dev, and have forgotten. The business of getting
>>>> gentoo up on this box was chaotic and stressful for a variety of
>>>> reasons, som not related to Linux or gentoo. I could have created
>>>> that entry to satisfy /etc/fstab, I suppose, particularly because
>>>> IIRC devfs didn't get configured by default and I was having
>>>> trouble completing the boot process. But maybe that's not it -- if
>>>> devfs wasn't working, there's no way I would have set it up using
>>>> that long pathname, because at that point I would not have know
>>>> what it was.
>>>>
>>>
>>> Just a WAG on my part. The kernel knows about the / partition at boot
>>> because it is passed this information from lilo (or grub). That's
>>> probably how devfs can create a /dev/root symlink that points to the
>>> proper partition. The /boot partition (if you have one) needs the
>>> actual partition to be mounted because the kernel can't guess where
>>> you want that, or any other partition for that matter.
>>>
>>> BTW, I have a /dev/root and don't have a reference to it in fstab or
>>> anywhere in /etc/devfsd.conf. I guess it just does that on it's own.
>>>
>>> Bill
>>>
>>> --
>>>
>>
>>
>> I bet you get the culprit!
>>
>> [19:12] [sko@slowdown:~]$ ls -l /dev/root
>> lr-xr-xr-x 1 root root 4 Oct 24 17:26 /dev/root -> rd/0
>>
>> In my /etc/lilo.conf I boot this entry:
>>
>> image=/boot/kernel-2.6.9
>> label=269
>> append="root=/dev/ram0 real_root=/dev/hda2 init=/linuxrc
>> splash=verbose"
>> initrd=/boot/initrd-2.6.9
>> vga=0x317
>>
>> They _must_ be related, don't they?
>>
>> If you have genkernel installed see:
>> #cat /usr/bin/genkernel | tail -n 40
>> and discover where my append line came from...
>>
>> Ciao
>> Francesco
>>
>>
>>
> I don't have /dev/root. I do use genkernel but I'm using gensplash so
> I'm not using the initrd and my kernel append part is a little
> different for that reason but yes if your using root=/dev/ram0 that
> has to be where it's coming from
>
> title Gentoo
> root (hd0,0)
> kernel (hd0,0)/boot/kernel-2.6.8-ck7 root=/dev/hda3
> video=vesafb:ywrap,pmipal,1024x768-32@85 \
> splash=silent,theme:emergence init=/linuxrc
> initrd (hd0,0)/boot/fbsplash-emergence-1024x768
>
> --
> gentoo-user@gentoo.org mailing list
>
i dont mean to go off-topic here but can you explain the 'ywrap,pmipal'
part of your config? what does it do for you? i can never get that to
work properly, again sorry for going off-topic

nick

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Re: Re: Special /etc/fstab entries [ In reply to ]

res0r9lm at tampadsl

Oct 24, 2004, 9:15 PM

Post #9 of 9 (346 views)

Permalink

Nick Smith wrote:

> Ralph wrote:
>
>> Francesco Talamona wrote:
>>
>>> On Sunday 24 October 2004 19:26, Bill Davidson wrote:
>>>
>>>
>>>> On 13:21 Sat 23 Oct , Kevin O'Gorman wrote:
>>>>
>>>>
>>>>> Well, the odd thing is that after booting, /dev/root is actually
>>>>> what's being used, as shown by the 'df' output (in part):
>>>>> /dev/ROOT 19538240 11193236 8345004 58% /
>>>>>
>>>>> I could well be having a senior moment. It could be that I created
>>>>> this entry in /dev, and have forgotten. The business of getting
>>>>> gentoo up on this box was chaotic and stressful for a variety of
>>>>> reasons, som not related to Linux or gentoo. I could have created
>>>>> that entry to satisfy /etc/fstab, I suppose, particularly because
>>>>> IIRC devfs didn't get configured by default and I was having
>>>>> trouble completing the boot process. But maybe that's not it -- if
>>>>> devfs wasn't working, there's no way I would have set it up using
>>>>> that long pathname, because at that point I would not have know
>>>>> what it was.
>>>>>
>>>>
>>>>
>>>> Just a WAG on my part. The kernel knows about the / partition at boot
>>>> because it is passed this information from lilo (or grub). That's
>>>> probably how devfs can create a /dev/root symlink that points to the
>>>> proper partition. The /boot partition (if you have one) needs the
>>>> actual partition to be mounted because the kernel can't guess where
>>>> you want that, or any other partition for that matter.
>>>>
>>>> BTW, I have a /dev/root and don't have a reference to it in fstab or
>>>> anywhere in /etc/devfsd.conf. I guess it just does that on it's own.
>>>>
>>>> Bill
>>>>
>>>> --
>>>>
>>>
>>>
>>>
>>> I bet you get the culprit!
>>>
>>> [19:12] [sko@slowdown:~]$ ls -l /dev/root
>>> lr-xr-xr-x 1 root root 4 Oct 24 17:26 /dev/root -> rd/0
>>>
>>> In my /etc/lilo.conf I boot this entry:
>>>
>>> image=/boot/kernel-2.6.9
>>> label=269
>>> append="root=/dev/ram0 real_root=/dev/hda2 init=/linuxrc
>>> splash=verbose"
>>> initrd=/boot/initrd-2.6.9
>>> vga=0x317
>>>
>>> They _must_ be related, don't they?
>>>
>>> If you have genkernel installed see:
>>> #cat /usr/bin/genkernel | tail -n 40
>>> and discover where my append line came from...
>>>
>>> Ciao
>>> Francesco
>>>
>>>
>>>
>> I don't have /dev/root. I do use genkernel but I'm using gensplash so
>> I'm not using the initrd and my kernel append part is a little
>> different for that reason but yes if your using root=/dev/ram0 that
>> has to be where it's coming from
>>
>> title Gentoo
>> root (hd0,0)
>> kernel (hd0,0)/boot/kernel-2.6.8-ck7 root=/dev/hda3
>> video=vesafb:ywrap,pmipal,1024x768-32@85 \
>> splash=silent,theme:emergence init=/linuxrc
>> initrd (hd0,0)/boot/fbsplash-emergence-1024x768
>>
>> --
>> gentoo-user@gentoo.org mailing list
>>
> i dont mean to go off-topic here but can you explain the
> 'ywrap,pmipal' part of your config? what does it do for you? i can
> never get that to work properly, again sorry for going off-topic
>
> nick
>
> --
> gentoo-user@gentoo.org mailing list
>
>
>
if your still using vga= with gensplash that could be your problem

pmipal - Use the protected mode interface for palette changes

ywrap - Same as ypan, but assumes your gfx board can wrap-around
the video memory (i.e. starts reading from top if it
reaches the end of video memory). Faster than ypan

ypan - enable display panning using the VESA protected mode
interface. This enables the Shift-PgUp scrollback
thing and greatly speeds up fullscreen scrolling.
It is slower than "redraw" when scrolling only a halve
screen. This is the default.

mtrr - setup memory type range registers for the vesafb framebuffer

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