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<H2><A NAME="s7">7. Installation/UN-installation and some tricks</A></H2>
<P>The installation of a <EM>Umsdos</EM> is not much different
from the installation of an ordinary (<EM>Ext2 based</EM>) <EM>Linux</EM>
system.
<P>There are two main differences.
<P>
<H2><A NAME="ss7.1">7.1 The pseudo-root <CODE>/mnt/linux</CODE></A>
</H2>
<P>The normal steps for an installation are
<P>
<OL>
<LI>Setting a partition with fdisk and formatting it.</LI>
<LI>Mounting it as /mnt relative to our installation
root disk.</LI>
<LI>Copy all packages into <CODE>/mnt</CODE>.</LI>
</OL>
<P>With <EM>Umsdos</EM>, the step 1 is not required (wasn't it the goal
of <EM>Umsdos</EM> not to reformat ?).
<P>It is possible to install a <EM>Umsdos</EM> system just by copying
all packages into <CODE>/mnt</CODE>. This will certainly work. But it
will create a
bunch of subdirectories into your <EM>DOS</EM> root directory (C:) and
you won't like it. This is the reason all <EM>Umsdos</EM> installation
use the pseudo-root. And this is the major difference between
a normal <EM>Ext2</EM> installation and a <EM>Umsdos</EM> one: All files
are copied into <CODE>/mnt/linux</CODE>.
<P>
<H2><A NAME="ss7.2">7.2 Preparing <CODE>/mnt/linux</CODE></A>
</H2>
<P><CODE>/mnt/linux</CODE> is not an ordinary directory. It has to
be promoted so it will correctly handle <EM>Linux</EM> long file name
and special files (links, device). The step required to
setup <CODE>/mnt/linux</CODE> are:
<P>
<OL>
<LI><CODE>mkdir /mnt/linux</CODE></LI>
<LI><CODE>umssync /mnt/linux</CODE></LI>
</OL>
<P>That's it!
<P>
<H2><A NAME="ss7.3">7.3 Making sure <CODE>/mnt/linux</CODE> is correctly setup</A>
</H2>
<P>Even if the setup of <CODE>/mnt/linux</CODE> is pretty simple, there
are many installation package out there who get it wrong. How can ?
<P>The biggest installation problem come from an incompatible
<CODE>umssync</CODE> program. <EM>Umsdos</EM> has been update in
linux 1.1.88 (Can't remember exactly) and a flaw was uncovered
in <CODE>umssync</CODE>. To avoid confusion in the <EM>Linux</EM>
community, it was decided to raise the compatibility
level required for all <EM>Umsdos</EM> tools. Old version
of the tools were simply rejected.
<P>It sounds like many distribution did not update their
<CODE>umssync</CODE> utility on the installation disk.
<P>There are still many distribution like this out there. The net result
is that the directory <CODE>/mnt/linux</CODE> is not promoted at all
and will truncate all long file name and will reject all special
file.
<P>It is possible to do a test very early during the installation to
find out if something went wrong. Thanks to the pseudo console
mechanism of <EM>Linux</EM>, you can do that without leaving the
installation program. Do the following steps:
<P>
<OL>
<LI>Press <CODE>Alt-F2</CODE> (<CODE>Alt</CODE> key at the same time
as the <CODE>F2</CODE> key).</LI>
<LI>login as root.</LI>
<LI><CODE>cd /mnt/linux</CODE>
If this fail, you are trying this too early. A good time
to do this is at the end of the packages selection.</LI>
<LI><CODE>>TOTO</CODE></LI>
<LI><CODE>ls -l</CODE>
You should see an empty file <CODE>TOTO</CODE> in uppercase. If you
see it in lowercase, something went wrong. Try to do
the <CODE>umssync</CODE> step again. <CODE>umssync</CODE> can be use over
and over without problem.
<CODE>umssync .</CODE>
If there is no error message, try the <CODE>TOTO</CODE> test again.
If
<CODE>TOTO</CODE> appears fine, then all is OK. Something is strange
in this installation, but you just save it. Continue
</LI>
<LI>Press <CODE>Alt-F1</CODE> to get back to the installation screen.</LI>
</OL>
<P>If the test fail, the best fix is to get a newer installation
root disk. You can generally fix this root disk by installing
a newer version of <CODE>umssync</CODE>. This is not difficult but
required a working <EM>Linux</EM> system. You simply have to
mount the root disk floppy and replace the offending
<CODE>umssync</CODE> with a new one.
<P>
<H2><A NAME="ss7.4">7.4 Oops releasing pseudo root ...</A>
</H2>
<P>Most <EM>Umsdos</EM> installation which fail, do this by printing
this strange message. This is not a bug in <EM>Umsdos</EM> although
the message looks strange. Here are the known causes.
<P>
<UL>
<LI>The most common one
<P>The <EM>Slackware</EM> installation try to setup a swap
file very early during the installation. To do so, it asks
you to select a partition (dos drive), then mount it and
set the swap file.
<P>When installing a <EM>Slackware</EM> system, you must setup
the target partition prior to install. This normally
mounts the <EM>DOS</EM> partition on <CODE>/mnt</CODE>, creates
the <CODE>/mnt/linux</CODE> directory and applies <CODE>umssync</CODE>
on it.
<P>This is where most problems come from. Most user just
forget the "setup target partition" step and go directly
to the rest of the installation. Since <CODE>/mnt</CODE> is
already mounted, this mistake goes unnotice.
This means that <CODE>/mnt/linux</CODE>
was not created properly (Not promoted). All special files
and links and long names can't be created properly.
<P>
</LI>
<LI>Invalid umssync utility
<P><CODE>/mnt/linux</CODE> was improperly setup-ed. Generally caused
by an improper <CODE>umssync</CODE> utility on the installation
root disk.
</LI>
<LI>Old bug in umsdos
<P>There was a bug in <EM>Umsdos</EM> prior to <EM>Linux 1.2.2</EM>. The
pseudo-root mode would not activate properly if the
file <CODE>/etc/init</CODE> was missing. <CODE>init</CODE> is now located
in <CODE>/sbin</CODE>. You can fix it by getting a newer kernel.
This is recommended because another bug was uncover and fixed
in 1.2.2.
<P>If you can't upgrade, do this
<P>
<OL>
<LI>Boot from you installation disk.</LI>
<LI>Login as root.</LI>
<LI><CODE>mount -t umsdos /dev/hdXX /mnt</CODE>
where <CODE>/dev/hdXX</CODE> is your <EM>DOS</EM> partition.</LI>
<LI><CODE>cd /mnt/linux/etc</CODE></LI>
<LI><CODE>ln -s ../sbin/init init</CODE></LI>
<LI><CODE>cd /</CODE></LI>
<LI><CODE>Ctrl-Alt-Del</CODE></LI>
<LI>Boot your <EM>Umsdos</EM> normally.</LI>
</OL>
</LI>
</UL>
<P>Unfortunatly, the first two (Installation problems) produce a completly
unusable installation. Uninstall it (See next section) and install
again.
<P>
<P>
<H2><A NAME="ss7.5">7.5 How to UN-install a <EM>Umsdos</EM> system</A>
</H2>
<P>One neat thing about <EM>Umsdos</EM> and its pseudo-root
mechanism, is that you can UN-install it without pain. You
just boot <EM>DOS</EM> and recursively delete the <CODE>linux</CODE>
directory. That's all. <EM>Umsdos</EM> requires no special
drivers in the config.sys, nor it creates anything
special outside of the <CODE>linux</CODE> directory.
<P>
<H2><A NAME="ss7.6">7.6 Moving a <EM>Umsdos</EM> system to another <EM>DOS</EM> drive</A>
</H2>
<P>This can be done from <EM>Linux</EM> or from <EM>DOS</EM>.
You just have to copy recursively the <CODE>linux</CODE> directory
from one drive to the other. After that you will have to
adjust you boot mechanism (generally loadlin command) and
the <CODE>/etc/fstab</CODE> file.
<P><EM>Umsdos</EM> can live on any <EM>DOS</EM> drive. There is no
need to install it on the <CODE>C:</CODE> drive, nor it is important
to have it on the first hard drive. It does not matter at
all.
<P>In fact, one may decide to have several <EM>Umsdos</EM> installations
on different drive just to do experiments.
<P>
<H2><A NAME="ss7.7">7.7 About installing 50 <EM>Umsdos</EM> systems.</A>
</H2>
<P>How about installing a bunch of <EM>Linux</EM> systems in no time ?
<P><EM>Umsdos</EM> systems are living in a <EM>DOS</EM> world. You can
take advantage of this if you wish to install <EM>Linux</EM> easily.
<P>You can install and configure a <EM>Umsdos</EM> system at your site.
When you are satisfied with the configuration and the different
packages you have selected, you can boot <EM>DOS</EM> and copy
the complete <CODE>linux</CODE> directory to your <EM>DOS</EM> file
server. Then you go to other <EM>DOS</EM> station and simply
copy the files on the network drive to the local drive.
That's it. Only adjust the boot script (<EM>Loadlinx</EM>) and go.
<P>With minimal adjustment (Host name, IP number), anyone will
be able to install a <EM>Linux</EM> system in a matter of minute.
<P>Interest readers may note that installing <EM>Linux</EM> systems
by copying running system also works for any other <EM>Linux</EM>
systems, including <EM>Ext2</EM> based one.
<P>One beauty of <EM>Linux</EM> is that there is no hidden files which
have to be install by magic installation program.
<P>
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