Next Previous Contents

2. Using the rescue partition

This chapter explains the various ways that the rescue partition can be used to recover a NetWinder back to its factory state. Keep in mind that this is normaly a `last resort' measure for fixing your system; often you can more easily repair the damage in other ways. The rescue partition can be used as an emergency boot device, which allows you to go and fix stuff on the main partition.

2.1 Overview

All recent NetWinder machines include a small (10 MB) rescue partition, that contains enough software to reformat the NetWinder's internal hard disk, and then to reinstall the normal software load. Naturally, an image of all the files on the hard disk is also necessary; for OfficeServer this image is included on the CDROM in the rescue folder.

In the most common scenario, the OfficeServer CDROM is placed into a PC that has network access, so that the NetWinder can retrieve the data from the CDROM via the network. It is necessary for the PC to have enabled file sharing, and a `shared folder' for the CDROM has to be created.

The NetWinder rescue partition is then booted, and networking is configured so that the PC can be reached. There are a series of scripts to guide you through the process of formatting and then mounting the NetWinder hard disk. Then, the drive image is retrieved from the CDROM on the PC and installed on the NetWinder hard disk. (There is also the option to fetch the drive image via FTP).

The following sections describe the process in greater detail.

2.2 Booting the rescue partition

When you need to use the NetWinder's rescue partition, here are the steps to access it. You'll need to connect a keyboard and monitor to the NetWinder to carry out this rescue process.

  1. Turn on your NetWinder (or reboot it, if it was running)
  2. Stop the autoboot sequence by as the NetWinder boots. (e.g. when it says `Press any key to abort autoboot')
  3. Type the following commands at the firmware prompt
            setenv kerndev /dev/hda4
            setenv rootdev /dev/hda4

That will do it, the NetWinder will now boot from the rescue partition. In short time, a shell prompt will appear, along with a message telling you to run netconfig to configure the network.

2.3 Configuring networking

The netconfig script will allow you to set up a network interface. It will ask a number of questions about your network, such as the IP address and netmask to be used. Some options, like DNS servers and gateways, are not required if your rescue computer is on the same subnet.

The netconfig script will ask you which interface to use. Normally, the OfficeServer uses eth1 (the 10/100-base-T port) for its internal gateway. So that is generally the one you would select. Then give an IP address and a netmask. The script will try to compute the broadcast address for you.

If you normally operate using DHCP, you'll have to `guess' a free IP address to be used during this rescue boot. Go to some other computer on your network, check out what it's IP address is, and then add one or two to the number. You can use ping or other tools to verify that the address is free for use. Then enter the free address into the NetWinder's script.

It is a good idea to test the network connection once it's been configured. From the NetWinder you can try to ping another machine on your network. DNS name resolution might not work, but numeric IP's should. Note that the rescue partition shell does not support job control, which means you cannot abort a ping with CTRL-C. Instead, you have to use ping -c 5 which tells ping to only try 5 times.

2.4 Now what?

At this point, there are five possible options for re-imaging the NetWinder's hard disk. Three of them are quite common:

  1. mountsmb is used if the rescue image is going to be loaded from a Windows 95/98/NT computer on your network,
  2. mountnfs is used if the rescue image is going to be loaded via NFS from a unix system on your network, and
  3. ftprescue is used if the rescue image will be downloaded by FTP from an FTP server.

In some cases, instead of connecting from the NetWinder to a rescue server, you'll want to turn the NetWinder into a server so that other computers can connect to it. If this seems like the same thing to you, then don't worry about it, and ignore the following options:

  1. nfsserver turns your NetWinder into an NFS server, with the root filesystem exported to the whole network,
  2. smbserver similary turns the NetWinder into a Samba server, so that other (Windows) clients can connect to it.

These options are described further in the following sections. There are a few more helpful scripts that are used, wipefs which erases the hard disk, and mountfs which mounts the partitions in preparation for the untarring of the disk image.

2.5 Using mountsmb

This is the option that most people will use. It requires that you have a computer running Windows on your network. You place the OfficeServer CD-ROM into this machine and allow the CD to be shared across the network. Click on `My Computer', then right-click on the CD-ROM icon. A menu will appear, select `Properties' and then click on the `Sharing' tab. Turn on sharing and give it a name, for example, `CDROM'.

On the NetWinder, you should now run the mountsmb script. It will ask for the name of the Windows computer (if you don't know what it is, then go to the Windows machine, right-click on `Network Neighborhood' and then click the `Identification' tab). Next, you'll be prompted for the name of the share (`CDROM' in the example above). Finally, you should enter the username (which matches the name you used to log into Windows). The NetWinder will then try to establish the connection to the Windows machine.

If the connection fails, you'll have to check your settings carefully and try again. Make sure the network cables are plugged in and that you can ping the Windows computer from your NetWinder, and vice-versa. Try entering the computer name and share name in uppercase, as some Windows systems seem to want it that way. If your DNS server is dodgy or nonexistant, then you'll need to use the IP address of the Windows machine in place of its name.

Once the mount is successful, then the contents of the CDROM should be visible on the NetWinder. To verify, type ls -l /mnt/rescue. You should see a directory called `recovery' (or `Recovery') and inside that directory, the OfficeServer disk image. You can now skip down to the Actual installation section to complete the process.

2.6 Using mountnfs

If you have other computers on your network that run a Linux or some other UNIX-like operating system, then this option is the one to use. Place the CDROM into the drive and then do whatever is necessary to mount and share the CD to the network. For Linux, this would mean mounting the disk (mount /dev/cdrom /mnt/cdrom) and then editing the /etc/exports file to allow the /mnt/cdrom directory to be shared. And then the NFS service would need to be restarted.

On the NetWinder, the mountnfs script will prompt you for the IP address (or name) of the rescue server, and the name of the share (e.g. /mnt/cdrom). It will then try to mount the volume so that it can be accessed on the NetWinder as /mnt/rescue.

If the mount fails, check the network cables, IP addresses, and the settings on your server. Try mounting the server from elsewhere on your network, to see if it is correctly configured. Often you have to restart both NFS and portmap services on the server. Try ping tests to verify that the NetWinder can talk to the server.

Once the mount is successful, then the contents of the CDROM should be visible on the NetWinder. To verify, type ls -l /mnt/rescue. You should see a directory called `recovery' (or `Recovery') and inside that directory, the OfficeServer disk image. You can now skip down to the Actual installation section to complete the process.

2.7 Using ftprescue

To be written.

2.8 Using nfsserver

To be written.

2.9 Using smbserver

To be written.

2.10 Actual installation

At this point, the new disk image you want to install should be mounted under /mnt/rescue somewhere, and you should know the exact path and filename. Since the CDROM's have the old DOS limitations on filenames, you may find that the image is called something strange, like os-1_0_2~.gz when really it should be something more meaningful like os-1.0-2.tar.gz. In the following examples, just substitute the actual filename for the examples listed.

You can now proceed to erase the hda1 and hda3 partitions and then to transfer, via the network, the new disk image on to the empty partitions. Two scripts are provided to facilitate this process: wipefs is used to clear the two disk partitions, and mountfs sets the partitions up so they can be accessed from /mnt/hdroot.

Note: there is a bit of a bug in the early versions of the rescue system. If you type cat /proc/version and it reports linux version 2.2.9-3, then you will likely have trouble with formatting the two partitions. The format command (mke2fs) will fail randomly with a `memory violation' error. If this happens to you, your options are to replace the kernel with a newer version (2.2.12), or to repeat the command until it suceeds, or to use rm -rf to delete all the files instead of mke2fs.

After you've used wipefs and mountfs, the new disk image can be installed directly. Just to keep you on your toes, we did not include a script for doing this. You have to type the commands yourself:

        cd /mnt/hdroot
        tar zxvpf /mnt/rescue/recovery/os-1.0-2.tar.gz

Adjust the pathname on the tar command as necessary to reflect the actual path and filename where the new image is located. It is critical to use the `p' option so that permissions will be set correctly on the files. The `v' option can be omitted if you don't want to see the names of the files scrolling by.

It should take about 15 minutes to copy all the data across. Once it's done, you should wait a little longer (30 seconds or so) to let the data be flushed to disk. Then, type exit, wait until the message appears that its safe to shutdown. Then press the reset button to reboot. At this point, the new image will be loaded and hopefully all will be well.

Next Previous Contents