On Thu, Nov 23, 2000 at 12:15:32PM +0100, Michael Schmitz wrote:
Re: mounting /etc readonly: how do you handle /etc/mtab in that case? :-)
Symlink it to /proc/mounts, of course. :)
/etc/mtab has always been evil, and not just because it's in the wrong
directory. It's about equivalent to the "route" or "ipchains" commands
keeping track of what _they_ thought the kernel settings were, and then if
you tried to list the routes or firewall rules, they would just cat the
file. Yuck.
Have fun,
Avery
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From: Michael Schmitz <hidden> Date: 2000-11-23 13:36:44
On Thu, Nov 23, 2000 at 12:15:32PM +0100, Michael Schmitz wrote:
quoted
Re: mounting /etc readonly: how do you handle /etc/mtab in that case? :-)
Symlink it to /proc/mounts, of course. :)
Good answer. I'd have used a symlink to some writeable directory on the
root fs, mainly because using /proc all over the place tends to confuse
Unix admins with no Linux experience. Let's not fall into the Solaris trap
(you are in a maze of twisty little config files, all different from the
rest of Unix').
/etc/mtab has always been evil, and not just because it's in the wrong
directory. It's about equivalent to the "route" or "ipchains" commands
keeping track of what _they_ thought the kernel settings were, and then if
you tried to list the routes or firewall rules, they would just cat the
file. Yuck.
It's not elegant, more something of a historic wart ... Unix is full of
that :-)
Michael
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From: Gabriel Paubert <hidden> Date: 2000-11-23 14:18:53
On Thu, 23 Nov 2000, Michael Schmitz wrote:
quoted
On Thu, Nov 23, 2000 at 12:15:32PM +0100, Michael Schmitz wrote:
quoted
Re: mounting /etc readonly: how do you handle /etc/mtab in that case? :-)
Symlink it to /proc/mounts, of course. :)
Good answer. I'd have used a symlink to some writeable directory on the
root fs, mainly because using /proc all over the place tends to confuse
Unix admins with no Linux experience. Let's not fall into the Solaris trap
(you are in a maze of twisty little config files, all different from the
rest of Unix').
At boot, before the first mount command executes, there may be _no_
writable directory and there may be none for a while, and you have the
problem of having an existing non-empty /etc/mtab (or equivalent) from a
non-clean shutdown which you would have to erase before the first mount is
done (adding another funky option to mount). Unless you make some kind of
ramdisk compulsory, which might not be bad idea after all with current
memory sizes.
Gabriel.
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From: Michael Schmitz <hidden> Date: 2000-11-23 18:40:04
quoted
Good answer. I'd have used a symlink to some writeable directory on the
root fs, mainly because using /proc all over the place tends to confuse
Unix admins with no Linux experience. Let's not fall into the Solaris trap
(you are in a maze of twisty little config files, all different from the
rest of Unix').
At boot, before the first mount command executes, there may be _no_
writable directory and there may be none for a while, and you have the
problem of having an existing non-empty /etc/mtab (or equivalent) from a
The init scripts of all distributions but SuSE handle this just fine
(mount -n). At least SuSE seems to mount the root fs rw from the start,
which causes all sorts of pain if you want to boot into a RedHat system
using the SuSE rescue disk. No idea how SuSE copes with readonly root fs.
Anyway, this wasn't the issue initially. It seems /proc/apm should be
doable on PPC for programs that don't use apmlib, and the apmlib glue code
takes care of the others.
non-clean shutdown which you would have to erase before the first mount is
done (adding another funky option to mount). Unless you make some kind of
ramdisk compulsory, which might not be bad idea after all with current
memory sizes.
Yeah, like Linux will never run on my old 4 MB Mac anyway.
Michael
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From: Gabriel Paubert <hidden> Date: 2000-11-24 14:23:56
On Thu, 23 Nov 2000, Michael Schmitz wrote:
The init scripts of all distributions but SuSE handle this just fine
(mount -n). At least SuSE seems to mount the root fs rw from the start,
which causes all sorts of pain if you want to boot into a RedHat system
using the SuSE rescue disk. No idea how SuSE copes with readonly root fs.
Yes, but read my previous posts. I consider the -n and -f mount options to
be a kludge. There is a chicken and egg problem and the workaround is a
kludge. The list of mounted file systems should be maintained by the
kernel IMHO, since the kernel has to know them in any case.
Mouting root read/write too early is even worse. That's no problem
since Suse waits for root fs to be checked before remounting rw. But Suse
has otehr problems when you want to maximize sharing on diskless systems
(init scripts in /sbin for one).
quoted
non-clean shutdown which you would have to erase before the first mount is
done (adding another funky option to mount). Unless you make some kind of
ramdisk compulsory, which might not be bad idea after all with current
memory sizes.
Yeah, like Linux will never run on my old 4 MB Mac anyway.
BTW: what is the minimum RAM to run Liunx/PPC these days ? My smallest
(quasi embedded) machines have 16Mb and I hope to keep these running for
at least 5 to 7 more years.
Gabriel.
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BTW: what is the minimum RAM to run Liunx/PPC these days ? My smallest
(quasi embedded) machines have 16Mb and I hope to keep these running for
at least 5 to 7 more years.
2.4.x runs reasonably well on a 8Mb machine here.
Takashi Oe
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