DECStation Linux installation HOWTO

DECStation Linux installation HOWTO

Overview

Getting the software
Setting up a boot and root FS server
Attaching a serial console
Netbooting
Partitioning a local disk
Installing Linux on a local partition
Booting with a local root FS
Booting from a local disk
Adding packages to your system

Getting the Software

There is no nicely packaged DECStation linux distribution like RedHat, but there are lots of packages available that run on DECStation linux. So we'll have to download several files from different servers to get our system going. I will not go into detail about the packages needed on your (intel) boot server, the easiest way is to install a RedHat system, that includes most features you'll need.
At least you'll need the following packages installed: tftp, nfs-server, and bootp (besides standard networking setup).

For your DECStation, you need the following:

A boot kernel. Download a 2.4.18 ECOFF kernel from my kernel selector page.
A root filesystem that can be used as NFS-based root. This document uses mipsel-root-20011216.tgz

And lateron:

RPM Packages to expand your system. You can find lots and lots of packages on ftp.linux-mips.org.
The kernel source to compile your own kernel and start hacking!

Setting up the boot and root FS server

Most DECStations can boot from a bootp / tftp server (some can only boot from a MOP server, I have no information about MOP servers on linux). So now we have to setup bootp, tftp, and NFS export on your server. These examples all come from a i386 linux box running RedHat linux, the actual location and/or your file syntax may be different on your server. When in doubt, consult your manuals.

Before setting up your server, you must have allocated an IP address in the same subnet your ethernet card is connected to. Also you'll have to note the Ethernet address of your DECStation.

NFS server for your root filesystem

Your server will provide a root filesystem for your DECStation over NFS. In order to do that, you'll have to configure NFS, export a part of your filesystem to the DECStation (that means, give the DECStation permission to access that part of the server's filesystem).

Install the nfs-server package.
Make a directory to contain the root filesystem for the DECStation, for example /export/mips.
Edit the /etc/exports file to allow access from your DECStation to /export/mips.

/export/mips decstation(rw,no_root_squash)

decstation

Extract the mipsel-root-20011216.tgz in /export/mips

TFTP Server for the DECStation kernel

The TFTP server is needed only for downloading the kernel binary from your server to your DECStation. The tftp protocol is a very simple protocol, and has no security at all. That's why usually tftp servers are only used on boot servers, and most likely tftp is not configured on your linux system by default. Due to the lack of security, tftp server run 'chroot' , that means that they change their root location to some special directory, that only contain the bootfiles that must be accessable by tftp, and no other files. The usual location for these files is /tftpboot.

To set up your tftp server:

Install the tftp package
Add the tftp daemon to /etc/inetd.conf:

tftp dgram udp wait root /usr/sbin/tcpd in.tftpd /tftpboot

Create the /tftpboot directory.
Copy the kernel image file from the tar archive (path boot/vmlinux.ecoff) to /tftpboot/vmlinux.ecoff.

Bootp for booting your DECStation

Follow these steps to configure your bootp server.

Install the bootp package
Make sure your /etc/inetd.conffile contains a line like:

bootps dgram udp wait root /usr/sbin/tcpd bootpd -d 9 -c /tftpboot

Edit the /etc/bootptab file to contain the info needed for booting:

decstation:\

:ht=1:\

:ha=08002b376376:\

:ip=10.10.1.12:\

:bf="vmlinux.ecoff":\

:sm=255.255.255.0:\

:gw=10.10.1.4:\

:rp="/export/mips":\

:td=/tftpboot:\

:hd=/tftpboot:\

:hn:

ha=

rp=

Under some conditions (depending on the software version of your server), you might need static arp entries to get the decstations booting:
Add the following to your favourite rc file eg. /etc/rc.d/rc.local.

/sbin/arp -s 10.10.1.12 08:00:2b:37:63:76

Finally it might be a good idea to restart your server (or at least, restart NFS, and send a SIGHUP to inetd).

Attaching a serial console

The current state of the DECStation port doesn't include support for all framebuffer cards. So we use a serial terminal as system console. I myself use kermit on my server to access the serial console. This has the extra advantage, that you can log the session to a file on your server. This is very usefull for debugging, or sharing your success with fellow hackers :-).

Please note: The current kernels require a DEC LKxxx keyboard to be attached in order to boot. Please keep the keyboard connected!

DEC normally uses the PRINTER port for serial consoles, not the 'communication' port, that port is reserved for modems. So, depending on your model, you'll have to search for a port (DB25 or DEC modular connector) labeled as printer port. You might need a NULL-modem cable to connect to your terminal (or PC serial port), depending on your model and cable.

For my 5000/260 I have to use the port labeled (communications port 3).

Next you have to change the console from the keyboard / internal frambuffer to the serial port. This is done by setting a NVRAM environment variable. It might be best to consult your manual what value is used with your model. See the table below for a list of console settings.
Now power-toggle your DECStation, and the selftest and prom messages should appear on the serial console.

Normally, the serial console is auto-selected when the system is powered-up WITHOUT a video card So you could try to pull out the video card, and start the system with just the serial console plugged in.

Netbooting

If everything went OK until now, you should have your setup ready for the first linux boot attempt. Because Linux can not autodetect where the console is located, we have to supply boot arguments to the kernel, specifying the console. This depends on the DECStation model, but you might try several possible options in sequence if you don't know which one to use. My DECStation 5000/260 uses ttyS2. Secondly, we have to specify the root location. Assuming we have correctly configured bootp, we can just specify /dev/nfs as root FS. Finally we have to add the 'rw' argument to let the kernel mount the NFS root filesystem read-write (default is read-only, which doesn't make sense on a NFS root).

OK, now for the DECStation magic to boot over bootp / tftp. Lets try one of the following command:
>>boot 3/tftp/vmlinux.ecoff console=ttyS2 ip=bootp root=/dev/nfs single rw (for DECStation 5000)
>>boot -f tftp()vmlinux.ecoff "console=ttyS3 ip=bootp root=/dev/nfs single rw" (for DECStation 3100, note the quotes!)
See the table below for other models.

The digit '3' for the 5000 should be replaced by the module number containing the network card. You can find out what modules are in your system by giving the 'cnfg' command at the prom prompt.

You might want to watch the messages file on your server for messages from the bootp / tftp daemons. If the boot fails, they might provide usefull information on what went wrong.

Now, assuming your server sends you a kernel, you should see something like the following:

2224128+0+172576
This DECstation is a DS5000/200
CPU revision is: 00000220
FPU revision is: 00000320
Primary instruction cache 64kb, linesize 4 bytes
Primary data cache 64kb, linesize 4 bytes
Linux version 2.4.16 (root@elrond) (gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-96.1)) #6 Fri Dec 21 16:59:26 MET 2001

If it stops before 'This DECstation is a ...', the tftp file might not be transferred correctly. Some DECStations only allow kernels smaller than 1Mb to be loaded over tftp. I have no solution to that at this time.

The message 'This DECstation is a ...' is the last message printed through the prom-io. Thus if this is your last line of output, you possibly have a wrong 'console=' argument.

The correct location for your root FS will be passed to the DECStation by your bootp server. We start first booting single user only, because the getty process might have troubles using your serial line (mine at least has).

You will get some 'FAILED' messages from the RedHat startup, but these can be ignored for now.

If all goes well, you finally should see something like:

Enabling swap space.
Initializing random number generator...
bash#

Congratulations, you have just succesfully booted linux on your DECStation!

You might try to continue, and go on to multi-user mode. Just type 'exit' to the bash prompt, and init will boot to level 3.
After a while you should get a console login prompt.
Now xinetd should be running, and even if you can't get the console login prompt to work, you might try to log in over telnet. There is a guest account without a password, and the root account has no password too, so you should be able to log in.

If you don't get this working, maybe the troubleshooting guide has some hints for you.

Partioning a local disk

If your kernel has recognised your SCSI adapter, and has detected a local SCSI disk, you might be brave, and try to install Linux on your local hard disk. You should have seen messages like the following during your boot:

SCSI ID 7 Clock 25 MHz CCF=0 Time-Out 167 NCR53C9x(esp236) detected
ESP: Total of 1 ESP hosts found, 1 actually in use.
scsi0 : ESP236
scsi : 1 host.
Vendor: DEC       Model: RZ58     (C) DEC Rev: 0100
Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sda at scsi0, channel 0, id 2, lun 0
Vendor: DEC       Model: RZ58     (C) DEC Rev: 0100
Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sdb at scsi0, channel 0, id 3, lun 0
scsi : detected 2 SCSI disks total.
esp0: target 2 [period 200ns offset 15 5.00MHz synchronous SCSI]
SCSI device sda: hdwr sector= 512 bytes. Sectors= 2698061 [1317 MB] [1.3 GB]
esp0: target 3 [period 200ns offset 15 5.00MHz synchronous SCSI]
SCSI device sdb: hdwr sector= 512 bytes. Sectors= 2698061 [1317 MB] [1.3 GB]

Beware, the next step will wipe out all information on the disk!

The only partition format that we can create with DECStation linux at the moment is a DOS-type partition table. The kernel recognizes several other formats, but fdisk will create a DOS-type table by default. Try creating a linux native and a linux swap partition using 'fdisk /dev/sda'. I would suggest to make the first partition your root-fs, and use a second partition as swap space.
You should now see a kernel message that it has recognized the new partitions:

Partition check:
/dev/scsi/host0/bus0/target0/lun0: p1 p2

Then, we can go on to the real installation.

Installing Linux on a local partition

We are still running on our NFS-root, but we have a local disk with (at least) two partitions. We first try to create the filesystem:
# mke2fs /dev/sda1
Then, we initialise the swap partition:
# mkswap /dev/sda2
Now we mount the new filesystem:
# mount /dev/sda1 /mnt
And we copy our root-fs from the NFS server to the local partition:
# cd /
# tar clf - . | (cd /mnt; tar xpf -)

In order to get all things right, we have to edit the /etc/fstab file on your local disk FS:

change /dev/root to /dev/sda1, type ext2 instead of nfs

You might want to add your swap partition too.

After that, you should unmount the local disk, and shut down.

Booting with a local root FS

Assuming that you followed the example above, we now try to use the local disk as root device. Please note that this time we do want to mount the FS read-only by the kernel, so don't add the 'rw' argument.

>>boot 3/tftp/vmlinux.ecoff console=ttyS2 root=/dev/sda1 single (for DECStation 5000)

For other models, you should use the same boot command as for your netbooting, but add root=/dev/sda1, and remove 'rw'.
You can look for the following line during boot:
VFS: Mounted root (ext2 filesystem) readonly.
If it reads ext2, it should be your local disk. If you where able to run multi-user, using NFS root, you should be able to go to multi-user now too.

Booting from the local disk

To be able to boot from your local disk, you have to use the delo bootloader package (which is installed in the root image), place a ELF (not ECOFF) vmlinux kernel in the /boot directory. Edit /etc/delo.conf to reflect your correct root= and console= entries, and install the bootloader by running once:

# delo /dev/sda

(assuming that sda is your boot disk, and the disk where your root FS resides) You must use the whole disk device, and not a partition device file.
Now you can boot from your disk with the PROM command:

>>boot 3/rz0
(To boot from the scsi disk with ID=0, on a 5000/240)

The current delo only works on certain PROM version. At least my 5000/200 can't diskboot with delo.

Adding packages

The rpm command is on the root-system, so you can just use rpm to add packages. Packages for DECStation linux should be named *.mipsel.rpm, not *.mips.rpm. Lots of packages are available from ftp://ftp.linux-mips.org/pub/linux/mips. The root filesystem used in this HOWTO is based on RedHat 7.1 packages, more of these are available at ftp://ftp.linux-mips.org/pub/linux/mips/redhat/7.1

Models / Commands

Model	Console setting	Netboot command	Console port label
DECStation 2100	?	boot -f tftp() "console=ttyS3 ip=bootp root=/dev/nfs single rw"
DECStation 3100	setenv console 8	boot -f tftp() "console=ttyS3 ip=bootp root=/dev/nfs single rw"
DECStation 5000/20, /25, /33, /50	setenv console s	boot 3/tftp console=ttyS0 ip=bootp root=/dev/nfs single rw
DECStation 5000/120, /125, /133, /150	?	boot 3/tftp console=ttyS2 ip=bootp root=/dev/nfs single rw
DECStation 5000/200	setenv console s	boot 6/tftp console=ttyS3 ip=bootp root=/dev/nfs single rw
DECStation 5000/240, /260	setenv console s	boot 3/tftp console=ttyS2 ip=bootp root=/dev/nfs single rw