Linux/DECstation DECStation Linux Troubleshooting

Beware, this document is work in progress, and still incomplete!

Common problems with DECStation Linux

  1.  System will not netboot from tftp server.
  2.  Kernel boots OK, no output from init.
  3.  Read-only filesystem error messages during boot.
  4.  Single user runs OK, multi-user seems to hang.
  5.  Can't login in multi-user mode.
  6.  SCSI controller is not detected.
  7.  Neighbour table overflow error

System will not netboot from tftp server.

Some PROM revisions don't support tftp booting. This is not model dependant, but depends on the prom revision. For a list of known problems with DECStation PROMs regarding tftp booting, consult NetBSD list of DECStation proms. The only way to boot these systems is from local disk, of over the network using MOP (a DEC specific boot protocol). There is a mopd available for linux, but it doesn't seem to work with all ethernet cards. NetBSD on DECStation or VAX can act as a MOP bootserver. I have not tried to boot linux over mop, but it should be possible.

Kernel boots OK, no output from init.

If the last line of the console output is 'VFS: Mounted root ...', then somehow init can't open your console. This might be the result of an incorrect /dev/console device file. It should be:
crw--w----   1 root     tty        5,   1 Jan 27 19:09 /dev/console

To correct this, use the following commands:
# rm -f /dev/console
# mknod -m 620 /dev/console c 5 1

Read-only filesystem error messages during boot.

You probably forgot to specify the 'rw' argument to to boot command. The kernel mounts the root filesystem readonly by default. This is done to be able to fsck the root fs before mounting it read-write. For a NFS root system, this is not needed. Because of the generic entry in /etc/fstab (/dev/root instead of <server>:/<root-location>), we cannot remount the root fs.

Single user runs OK, multi-user seems to hang.

At least at my 5000/260, mgetty has troubles with the serial console port. I can get it to work, but not elegantly. Try telnetting into your DECStation to see if it is still alive.

Can't login in multi-user mode.

The login binary on declinuxroot-990128.tgz was compiled with -mips2, that means that it only runs on R4000 processors. This is solvend in the declinuxroot-current.tgz.

SCSI controller is not detected.

To bad, you'll have to wait, or write support for your SCSI card yourself.

Neighbour table overflow error

In linux 2.2.4, some changes where introduced in the IPv4 network stack. This results in ''neighbour table overflow" error messages while the kernel tries to mount it's root FS over NFS, when the client is far away from it's server and/or the network is busy. I'm trying to find what exactly causes this. I can't boot a 3100 at the moment due to that problem.

DECStation Linux Homepage
© Copyright 1998, 1999 The DECstation Linux Porting Team.
These pages are maintained by Karel van Houten (
Last change: 15-8-99