Troubleshooting

First Aid

If your problem isn't listed below and it's the middle of the night/weekend/etc and thus Dave and I aren't around, then you can (and should) try the following remedies before you use the helpdesk to register your problem. If the problem goes away after you've tried the following remedies, excellent.

If on a Windows machine: reboot it.

If on a Unix box: If you can open another terminal window, try to kill the offending process. Use the ps command (man ps) to identify the process ID or PID, then try

% kill -HUP pid

% ps -eaf | grep X
...
richard     1112 1111 30  Oct 17  ?   23:16:12 /usr/X11R6/bin/X :0 -auth 
...

General Problems

Is it a good idea to ask you about a problem when you're in the corridor on your way somewhere?
I've already emailed you about a problem and you've not replied.  Will it help if I email you again and again?

Login and Email Problems

I've forgotten my password.
My password won't let me in, but I'm sure I've remembered it correctly.
When I connect via telnet, I get in fine. But when I try to log into the desktop, it accepts the password, flickers briefly, then deposits me back to the CDE login box. [Unix only]
When I try to log into the desktop, it accepts the password, flickers briefly, then deposits me back to the RedHat login box. [Linux only]
I'm trying to ssh (Secure SHell) to a machine from the Solaris boxes and I see Entropy collection failed.
I'm trying to ssh (Secure SHell) to a machine and I see 'ssh_exchange_identification: Connection closed by remote host'.
I'm trying to ssh (Secure SHell) to a machine and I see 'Secure connection to hostname refused.'.
I'm trying to ssh (Secure SHell) to a machine and I see 'RSA host key for hostname has changed and you have requested strict checking.'
I'm trying to do X11 forwarding/telnet/ftp from outside the firewall.
My outgoing email has stopped outgoing.
My incoming email has stopped incoming.
Why aren't I getting email received/read receipts?
I get a message saying my email to someone@somewhere.com has failed, but I haven't emailed someone@somewhere.com!
Pegasus mail keeps freezing up.
Pine defaults to black on dark grey, and changing the colors makes it all weird

Software Problems

I'm running Windows and something has stopped working.
Star Office keeps crashing on me. [Unix only]
The web browser startup icon on the CDE doesn't work. [Unix only
I've deleted a file by mistake and I want it back
I've set a process running but I want to stop it.
I can't create any files (or save files from within an editor, or save a mail message).
What are these quotas then? And how can I get some more
I've tried to save a file in TextEdit and it's disappeared! [Unix OpenWindows only]
How can I keep on top of my quota?
I just double clicked on a file in FileManager and it's disappeared.[Unix only]
I just typed rm -r *.
How can I stop it asking if I really want to delete files?
I get the Ghostscript error "Error: /undefined in --get--"
I've written a script/program and get "permission denied" when I call it.
I've written a script/program and get 'command not found' when I call it.
I can't insert a Quicktime movie into MS Powerpoint
My file is full of ^M characters or little squares instead of newlines.
I'm WS-FTP-ing and it keeps crashing.
Acrobat reader fails to start
My_/tmp_filesystem_is_shrinking
I tried to run LaTeX and it won't work!
This X program is eating all my resources!
gnuplot doesn't work
Error while loading shared libraries?
There's a missing plugger.so
My Linux screensaver has locked up and I can't get back into my machine at the terminal.
Acroread says there's an error with a plugin
I'm trying to create/do something with a large file (> 2 Gb) and I have problems.
Mozilla doesn't know how to handle a file of type application/x-something.
Latex complains: 'found pdf version <1.6>, but at most version <1.4> allowed'

Network Problems

I can't get applications on the Linux server.
How do I troubleshoot a suspected network problem? I tried to telnet in to the AM network from outside the university, but it seems to hang.
Everything has frozen up, and I see 'NFS Server not responding' in a window.
When I boot my PC, instead of booting into Windows, I get a DOS-type name/password prompt that fails (whatever I type)  or mutters something about an Abnormal Boot and MAC address and deposits me in the L: drive, and nothing works from there.
When I log into Butterley, the Butterley messages window remains until I kill it manually. This is really irritating!
It says "telnet: Unable to connect to remote host: Connection refused"
I can't ftp to my AM Unix box from any machine outside the maths department.
I'm logged in remotely to HOST and I get 'Error: Can't Open display'.
I'm logged in remotely from HOST and I get 'Xlib: connection to "HOST:0" refused by server' when I call an X program.
Help! My computer is currently broadcasting an internet IP address!
Help! My home page has been hijacked and now always points to www.searchex.com!
I'm trying to download/do something with a large file (> 2 Gb) and I have problems.

Printer Problems

Hardware Problems

My mouse is erratic
My keyboard layout is wrong
How do I clean my keyboard?
I'm getting an ACPI BIOS error...

General Problems

Is it a good idea to ask you about a problem when you're in the corridor on your way somewhere/in a meeting/in the loo?

No, I'll forget.  Email me.  If it's important enough to bother me about, it's important enough to compose an email.

Also, if I send out an email regarding some topic, please don't just hit 'reply' and inform me of an unrelated problem.   Firstly, it's a pain for me when I'm searching through emails, which I do a lot - I receive around 150 work-related emails a day, and reference them by subject line.   Secondly, if it's important enough for you to bother me with, it's important enough to compose a fresh message about.

I've already emailed you about a problem and you've not replied.  Will it help if I email you again and again? Will it escalate the problem over other people's problems?

No.

Login and Email Problems

I've forgotten my password.

If it is a Linux or Solaris password on a box that we administer, I (or Dave Robson) can reset it to something else. (In the interests of security, please make it obvious that it is you making the request for a password change. Under no circumstances can I change anyone else's password for you.)

If it is a Novell password, or anything else adminstered by CICS, you will need to talk to CICS.

My password won't let me in, but I'm sure I've remembered it correctly.

Passwords are case-sensitive. Are you sure the CAPS LOCK hasn't been turned on? Are you sure you are typing in O or 0, or 1 or L or l, correctly? Are you trying to connect to one of the Physics machines (e.g. kepler, callisto) or one of the Linux machines (e.g. umbra, penumbra) where you don't have an account, instead of one of the acms machines?

When I connect to a machine via telnet or ssh in a terminal session, I get in fine. But when I try to log into the desktop, it accepts the password, flickers briefly, then deposits me back to the login box.

On the Sun machines: You're probably over your hard quota. Log in remotely and delete some files to bring you under your quota. Type

quota -v

When I try to log into the desktop, it accepts the password, flickers briefly, then deposits me back to the RedHat login box. [Linux only]

Comment out everything in your .cshrc file and try again. Success? Add them back in one at a time until it's fixed. If there are any commands in the .cshrc file that cannot be executed, RedHat is hugely picky about it, and tends to dump you out without explanation.

I'm trying to ssh (Secure SHell) to a machine from the Solaris boxes and I see Entropy collection failed.

Or, more fully, you see:

% ssh acms1
Couldn't connect to PRNGD socket "/var/spool/prngd/pool": No such file or directory
Entropy collection failed
ssh-rand-helper child produced insufficient data

I'm trying to ssh (Secure SHell) to a machine and I see 'ssh_exchange_identification: Connection closed by remote host'.

The /etc/hosts.allow and /etc/hosts.deny files in the target machine are refusing you access. Talk to the sysadmin of that machine.

I'm trying to ssh (Secure SHell) to a machine and I see 'Secure connection to hostname refused.'.

There are several possibilities, all of which involve the sshd daemon failing to see the incoming request:

• The sshd daemon isn't running on hostname (is it installed?). If you can get onto hostname by other means (e.g. console access) type 'ps -eaf | grep sshd'. Is it there? If not, contact the administrator to get it running again.
• The sshd daemon is running but isn't listening on the right port. Look at /etc/ssh/sshd_config. Is it listening on port 22?
• Only fixable by root users The packet is being filtered before it reaches the sshd daemon. To check for this, kill the daemon and restart it manually with the -d -d -d option, then attempt to connect. If the packet is being filtered before it gets to sshd, then it won't respond at all. What you need to do is change the ipchains or iptables to allow ssh connections on port 22. Type ipchains -L --line-numbers. You should get something like this:
  

  
  [root@tad ~]# ipchains -L --line-numbers
  Chain input (policy ACCEPT):
  num  target     prot opt     source                destination           ports
  1    ACCEPT     udp  ------  acheron.shef.ac.uk   anywhere              domain ->   any
  2    ACCEPT     all  ------  anywhere             anywhere              n/a
  3    REJECT     tcp  -y----  anywhere             anywhere              any ->   0:1023
  4    REJECT     tcp  -y----  anywhere             anywhere              any ->   nfs
  5    REJECT     udp  ------  anywhere             anywhere              any ->   0:1023
  6    REJECT     udp  ------  anywhere             anywhere              any ->   nfs
  7    REJECT     tcp  -y----  anywhere             anywhere              any ->   x11:6009
  8    REJECT     tcp  -y----  anywhere             anywhere              any ->   xfs
  Chain forward (policy ACCEPT):
  Chain output (policy ACCEPT):
  

  Right, what this is saying is that first, it accepts any packets from acheron (the uni nameserver) (rule 1). Then it accepts everything else (rule 2). Then it rejects any tcp connection to any port between 0 and 1023 (rule 3), also any tcp nfs request (rule 4), etc, etc.

  What you need to do is to add in a rule that accepts ssh requests to port 22 before everything is rejected. The syntax for this (in this case) will be:

  
  ipchains -I input 3 -j ACCEPT -i eth0 -s any/0 --dport 22 -p tcp
  

  Then another ipchains -L --line-numbers should result in this line appearing in the rules list:

  
  3    ACCEPT     tcp  ------  anywhere             anywhere              any ->   ssh
  

  ipchains only persist for the lifetime of the kernel (ie, until you log out) so you need to execute

  
  # /etc/init.d/ipchains save
  

  Newer kernels use iptables instead of ipchains. I am led to understand that the syntax is similar.

I'm trying to ssh (Secure SHell) to a machine and I see 'RSA host key for hostname has changed and you have requested strict checking.'

You ssh to a remote host and see something like this:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.

The fingerprint for the RSA key sent by the remote host is
98:43:65:ba:4e:31:d1:87:16:51:c6:4d:a7:73:74:93.
Please contact your system administrator.
Add correct host key in /home/cesar/.ssh/known_hosts to get rid of this
message.Offending key in /home/cesar/.ssh/known_hosts:6
RSA host key for remotehost.somewhere.ac.uk has changed and you have
requested strict checking.
Host key verification failed.

The authenticity of host 'remotehost.somewhere.ac.uk (123.132.123.132)' can't be established.
RSA key fingerprint is 1a:27:1f:84:05:af:2a:86:8a:24:7e:67:8a:e7:50:f2.
Are you sure you want to continue connecting (yes/no)? 

I'm trying to do X11 forwarding/telnet/ftp from outside the firewall.

http://www.shef.ac.uk/cics/facilities/fw.html

My outgoing email has stopped outgoing.

CICS have recently blocked outgoing mail not routed through mailhost or the Novell system. Have you read their instructions for configuring mail programs?

My incomping email has stopped incoming.

CICS's virus scanner (which all incoming email must pass through) occasionally gets overwhelmed and sluggish.  Be patient, young grasshopper.

Software Problems

I'm running Windows and something has stopped working.

Try saving all your open files if you can, and rebooting.

Star Office keeps crashing on me. [Unix only]

Don't use Star Office, use Open Office.

The web browser startup icon on the CDE doesn't work. [Unix only]

Bring up a terminal and type

mozilla &

instead.

I've deleted a file by mistake and I want it back!

However, see this question to see if they have been backed up.

If you do think that you've deleted a file and want us to recover it from the tapes, please email us full details of the file and the path, eg "Please can you see if you can retrieve /home/richard/docs/important/vital/victoria_sponge_recipe.doc".   

I've set a process running but I want to stop it. How do I stop it?

(Alternatively: there's an invisible Netscape process running that prevents me re-starting Netscape) (alternatively: I've accidentally visited a porn site and it keeps spawning new Netscape windows every time I try to kill it!) There are a number of ways to get rid of pesky processes (this applies to Unix machines):

• Control-C is an ungraceful but usually effective way to kill a process, but depends on that process being active and in the foreground and the machine being awake enough to recognise your Ctrl-C.
• [Unix - Solaris only]Alt-F4 usually will kill the active window.
• Open a new terminal window. (If the process is thrashing your display so hard that this is impossible, go to another computer and open a terminal window on the affected workstation). Type

  ps -eaf | grep process-name-partial-match

  For example

  ps -eaf | grep netscape

  . You'll see something like the example below (with different numbers)

  ap1rb	2058	2057	0	Nov 29	?	1:41	/usr/local/netscape/4.75/netscape
  ap1rb	2057	1	0	Nov 29	?	0:00	/bin/sh /usr/local/bin/netscape
  ap1rb	3860	3830	0	16:05:16	pts/14	0:00	grep netscape

  Identify the process(es) that you want to kill by their process ID (PID), which is the second column. In this case, the two processes are PID 2057 and 2058. (Note that PID 3860 here is the grep process that you've just used to produce this listing.) Type

  kill PID

  for all the PIDs related to your rogue process, (eg 'kill 2057') and retype your

  ps -eaf | grep processnamematch

  If they are still there, try

  kill -9 PID

  This should kill anything, although possibly may leave a core dump file (a huge diagnostics file that clutters up your directories). Remove it.

I can't create any files (or save files from within an editor, or save a mail message).

You've probably exceeded your filestore quota on your home directory. Type

quota -v

to check. If so, delete some files.

What are these quotas then? And how can I get some more?

Home filestore is set up to restrict the amount of space you can use (so that everybody gets a fair share). Each user has 3 numbers called 'usage', 'quota', and 'limit' (do a

quota -v

to see these). 'usage' gives the total filestore used by you at this moment (in Kb). 'quota' is a soft limit on usage - if you exceed this, you've got 3 days to get back under 'quota' again - after that your filestore is frozen until you do. If you try to exceed 'limit', your filestore is frozen immediately, and you must delete some files at once. In general, you can't get any more. File storage on the server (which is where your home directory is kept) is at a premium. You will need to buy some disk space on a local machine.

I've tried to save a file in TextEdit and it's disappeared! [Unix OpenWindows only]

Another quota problem. The OpenWindows text editor seems to delete the backup file before it's checked whether the 'save' succeeded (if it checks at all). So you end up losing both. Moral - if you run into this constantly, use a decent editor (like emacs) and/or a decent window system (like CDE).

How can I keep on top of my quota?

You'll only know you have a quota problem if you're logged in to the machine which has your home filestore physically connected, and this is unlikely on a network. Try running 'xquota' in the background. It will display the current state of affairs in a small window, and tell you when anything significant happens. It gets more and more frantic as you approach your limit.

I just double clicked on a file in FileManager and it's disappeared.[Unix only]

Don't use FileManager - it doesn't work. Evidence? - you just supplied it.

I just typed rm -r *.

Oh dear! Approach System Manager immediately on hands & knees. If you think you might be daft enough to type this, you should make sure rm is aliased to 'rm -i' (and similarly for mv and cp...) in your .cshrc (assuming that you're using the t-shell).

How can I stop it asking if I really want to delete files?

Make sure that rm isn't aliased to 'rm -i' in your .cshrc.    But, see the previous question.

I tried to manipulate a postscript file using a program that calls Ghostscript (e.g. ps2epsi) and I get an error message that looks like this:

Error: /undefined in --get--
Operand stack:
   tmpfontname   --dict:8/8(L)--   FontName
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   2   3   %oparray_pop   --nostringval--   --nostringval--   false   1   %stopped_push   1   3   %oparray_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--
Dictionary stack:
   --dict:907/941(G)--   --dict:0/20(G)--   --dict:53/200(L)--   --dict:24/30(L)--   --dict:111/300(L)--   --dict:24/30(L)--
Current allocation mode is local
Current file position is 8688
Aladdin Ghostscript: Unrecoverable error, exit code 1

This is due to a bug in earlier versions of Ghostscript. You need to update to (at least) Ghostscript 7.0.

I've written a script/program and get "permission denied" when I call it.

You'll need to add execute permission to the file. Look at the man page for 'chmod' to get the correct file permissions that you require. As an example, try

chmod 755 filename

or

chmod u+x filename

I've written a script/program and get 'command not found' when I call it.

Is the directory where you stored the script/program on your path? No? Add it. Are you using the C-shell (csh)? Yes? This is a hashing problem. The C-shell keeps a hash table of executable names on your current path to speed up searching when you type a command name. If you create a new command, you have to update the hash table with 'rehash'.

I'm trying to import a quicktime movie (.MOV) into Powerpoint, and I get the following error:

Powerpoint couldn't insert a movie from the selected file. Either the file is non-standard, or QuickTime is not installed properly.

In short, you can't, but there are workarounds. This is Microsoft's Answer

My file is full of ^M characters...

This is often because you've created a file in a DOS or Mac environment and ported it to Unix. The ^M character (actually Ctrl-V Ctrl-M, not caret-M) is a DOS/Mac/Windows/VMS carriage return, which is not needed in Unix. (In DOS etc, a newline is actually two characters: ^M carriage return, CR, and ^J linefeed, LF. In Unix, a newline is simply ^J linefeed, LF. This is a leftover from the days of teletype consoles - wonderful pieces of kit.) You can remove them most easily with the tr command:

tr -d '\015' < oldfile > newfile

for i in *
do
j=$i
mv $j $j.unstripped
tr -d '\015' < $j.unstripped > $j
done

...or little squares instead of newlines.

This is often because you've created a file in a Unix environment and ftp'd it to DOS in binary, not ASCII, format.   Go back and ftp it in ASCII format.

I'm WS_FTPing and it keeps crashing.

WS_FTP, available on the campus network and elsewhere, gets unhappy about filenames starting .# (dot-hash).

Acrobat reader fails to start

Acrobat reader fails to start on Linux with a message something like this:

% ./acroread
Warning: charset "UTF-8" not supported, using "ISO8859-1".
Aborted

This is a bug in some versions of Acrobat.   A good workaround is to set your language environment to C.  
Either add the line 

setenv LANG C

#!/bin/bash
#workaround for acroread not supporting UTF-8

# use the below line if you're doing this on Solaris
env LANG=C /software/packages/usr/local/Acrobat5/bin/acroread 

# use the below line if you're doing this on Linux
env LANG=C /software/bin/acroread 

#end acroread.sh

[richard@dyn006170 test]$ latex testfile.tex
This is TeX, Version 3.14159 (Web2C 7.3.1)
I can't find the format file `latex.fmt'!

This is Tex, Version 3.14159 (Web2C 7.3.1)
(Fatal format file error; I'm stymied)

/usr/X11R6/bin/X :0 -auth /var/gdm/:0.Xauth

/path/to/bin/gnuplot: error while loading shared libraries: libgd.so.2: cannot open shared object file: No such file or directory

% setenv LD_LIBRARY_PATH /software/lib

% setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/software/lib

/path/to/bin/program: error while loading shared libraries: somelib: cannot open shared object file: No such file or directory

% setenv LD_LIBRARY_PATH /software/lib

% setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/software/lib

Use the pdfpages package:

\usepackage{pdfpages} 
 

\includepdf[pages={1-6}]{file.pdf} 

  \pdfminorversion=6 

Network Problems

I can't see Applied2's /software

You're on a Linux box, and applications on /software (IDL, ENVI, etc) served from applied2.shef.ac.uk just don't work.  When you try a 'df -k', you get something like this, with silly values for the sizes of applied2:/software:

% df -k

Filesystem           1K-blocks      Used Available Use% Mounted on

/dev/hdb1             39516244   5942620  31566304  16% /

/dev/hda1               101086      8517     87350   9% /boot

none                    256544         0    256544   0% /dev/shm

/dev/hda3             38384904   6122264  30312752  17% /yesterday

applied2:/software   77371252437321868667518976         0 77371252437321868667518976   0% /software

The network's failed at some point and your mount has dropped.   Either get RLB or DJR to prod it, or reboot Linux (which will cure it, provided that applied is still up).

How do I troubleshoot a suspected network problem?

• Open up a web browser and try the following webpages. Can you successfully connect to them? Will they reload, showing you're not just viewing an old cached copy?
  • www.shef.ac.uk - shows that you have campus connectivity. Proves only that the machine is registered correctly and the campus network is up. If you can connect to campus webpages but nothing else, then this is either a YHMAN/JANET problem or a CICS problem.
  • www.google.com or news.bbc.co.uk - shows that you have off-campus connectivity, ie JANET is up. If you can connect to some external sites but not others, this is an off-site problem over which we have no control.
• Is the machine registered with CICS via connect@shef.ac.uk?
• Check that the network cable is plugged in. At both ends. Is it all physically undamaged?
• If you're using a hub or switch box (the 8 to 1 box plugged in the wall) try plugging the network cable into another slot. Try using another network cable. (Preferably one known to be working).
• If you're on a Windows machine, reboot it. If a daemon has fallen over, this may bring it back up successfully.
• If you're on a Windows machine and the Novell Client for Windows Login box comes up, click the Advanced box (to expand the screen). Select the NDS tag. Click "servers". Can you see the WINTERSETT server, under shef - Staff - stf3? Can you select it?
• If you're on a Windows machine and you have network connectivity inside the university but no access to Wintersett / your U: drive, then there's a problem either with Wintersett or with your Novell client.
• Do you get "Unknown Host" or "Unable to locate the server...." or "The page cannot be displayed" when you try to contact a foreign site, do you know the numeric IP of the site? If so, try that. Success with the numeric IP and failure with the name can mean that you can't talk to the DNS servers.

I tried to telnet in to the AM network from outside the university, but it won't connect - it just seems to hang.

You need to obtain a gateway account from CICS, 23050 or the Reception Desk. Then, telnet to gateway.shef.ac.uk, give your gateway username and password, and then you can telnet to AM Unix machines.

Everything has frozen up, and I see 'NFS Server not responding' in a window.

Acms1 has temporarily lost connectivity. Acms1 is our file- (and everything else-) server, so nobody can do anything until it has woken up. It should recover within a few minutes.

When I boot my PC, instead of booting into Windows, I get a DOS-type name/password prompt that fails (whatever I type) or mutters something about an Abnormal Boot and MAC address, and deposits me in the L: drive, and nothing works from there.

Reboot your PC (with Ctrl-Alt-Del). Watch carefully during the boot process; you should see the prompt 'Type H to boot from Hard Drive' (or something equivalent). This goes irritatingly quickly! At this point press 'H'. You now should see a successful boot into (local) Windows. Unfortunately you will need to do this every time you boot the PC - it is hardcoded into the BIOS of the network card supplied.

When I log into Butterley, the Butterley messages window remains until I kill it manually. This is really irritating!

Right-click on the title bar and select 'Remove window', then 'Apply'.

I can't telnet to any of the AM Linux boxes from anywhere; it says "telnet: Unable to connect to remote host: Connection refused"

The Linux boxes are (mostly) configured to reject telnet connections. You can only connect to them via secure shell (ssh). Make sure your machine is in /etc/hosts.allow on the linux box (ask the Linux box administrator to add it if it isn't). Then type

ssh -l username machinename

I can't ftp to my AM Unix box from any machine outside the maths department.

Only acms1 allows incoming ftps from outside the maths netgroup - use that.

I'm logged in remotely to HOST and I get 'Error: Can't Open display'.

If you're sitting in front of LOCALHOST and are connected to REMOTEHOST, type

localhost% xhost +REMOTEHOST

remotehost% setenv DISPLAY localhost:0

remotehost% netscape -display acms18:0

If an X client does not find such a command line option, it looks for an environment variable called DISPLAY. So you can set things up once and for all with 'setenv DISPLAY LOCALHOST:0'. If you've logged in locally on a workstation DISPLAY is automatically set for you on the local machine, so you only need to bother about it if you login remotely to another host. If the hostname (LOCALHOST) isn't recognized, you'll have to (find out and) use the host's IP number.

A variant on this comes when you ssh to one of our Linux boxes from one of our Unix boxes (popularly, from acms5). Attempting to run an X application results either in something like this:

[richard@tad ~]$ geomview
Error: Can't open display: 

[richard@tad ~]$ geomview
Xlib: connection to "acms21:0.0" refused by server
Xlib: Client is not authorized to connect to Server
Error: Can't open display: acms21:0

ssh -l username -X host

So you've done all that and it still says: "Error: Can't open display." What now? Well, you might be on a Linux box with fairly severe firewall setup (which is always a good thing) and an ipchains problem. Get root to type these words of wisdom:

# ipchains -I input 3 -j ACCEPT -i eth0 -s any/0 --dport x11 -p tcp
# /etc/init.d/ipchains save
# /etc/init.d/ipchains restart

I'm logged in remotely from HOST and I get 'Xlib: connection to "HOST:0" refused by server' when I call an X program.

(You may also see a similar message on your server console window). This is called an "authentication fail". When you first start up an X session, the X sever creates an authentication record, and writes it to your home directory in a file called .Xauthority. Only you have read and write access to this file. Any client program wishing to connect to the X server must supply the authentication details from this file. This is to stop other users and hosts on the network from interfering with your X session. If you are logged in to a remote host which doesn't have access to your home directory, then the server will refuse connection in this way. There are 2 ways round this:

• On the machine you originally logged into (your X session host), type

  xhost +HOST

  This will allow all clients on HOST to connect to your X server. This isn't very secure, as it doesn't stop interference from other users on HOST.

• Copy the authentication record from your X session host .Xauthority file to your HOST .Xauthority file. You will need to use the xauth program to do this. Assuming your X session was started on HERE, do the following on HOST:

  rsh HERE xauth 
  extract - $DISPLAY | xauth merge -

  For example:

  rsh acms21 xauth 
  extract - $DISPLAY | xauth merge -

  Note that you'll have to do this each time you start an X session. You can put it in your HOST .login file, or write a shell script or alias to do it.

Help! My computer is currently broadcasting an internet IP address!

You've been using a web browser and you suddenly see this!

Ignore it. Close it down without pressing 'OK' (Alt-F4 with the window highlighted usually does the trick) It's an incredibly annoying popup message from someone wanting to sell you dubious products by using scare tactics.

Help! My homepage has been hijacked to www.searchex.com!

Internet Explorer's home page switches immediately to www.searchex.com, regardless of your setting in Tools -> Options.

You've downloaded some software that has hijacked your home page. Go to an MS-DOS prompt (Start -> Programs) and type

CD C:\WINDOWS\SYSTEM  (for W98)
CD C:\WINDOWS\SYSTEM32 (for XP)
regsvr32 /u IEBrw.dll
regsvr32 /u HomePage.dll
regsvr32 /u HotLink.dll

(You will receive a warning message after each regsvr command; OK them). Now delete those three DLL files from the C:\WINDOWS\{SYSTEMS,SYSTEMS32} directory and reboot.

There is more information about this pest here:

• http://www.doxdesk.com/parasite/Searchex.html
• http://www.lavasoft.de/
• http://tiemdesign.com/features/hijacking.htm

 % wget host.somewhere.edu:/path/to/largefile

Printer Problems

The SPARG Inkjet refuses to print, and there's some lights on.

In normal use, there should be two lights on the front panel, both on continuous; the large left green light with a "transmission" icon, and the green power light (with the standard power icon) beside it.

If an ink cartridge has run out, it will refuse to print (rather than simply printing faded) and an amber light will glow steadily underneath the offending colour (black, cyan, magenta, yellow).    Press the small smoked plastic cover on the right hand side and it will pop open.  Pull the offending cartridge out and send to Kirsty in Pure Maths, who collects them.   Note the big black friendly number on the side.   Replace with one from Maureen, pressing gently but firmly down to seat it (the correct way round!).  Close the cover.   The offending light will extinguish and you will be able to print.

If any other lights are on, or any lights are flashing, consult Richard or Dave.

The Laserjet 5MP says "Toner Low" and the copies are very pale.

Dave or I can do this. But if we're not around for any reason, this is how to change the toner - it's no harder than changing the toner cartridge on an inkjet. First, get a new toner cartridge from the store - ask Maureen or Linda. For the Laserjet 5, the big reference number should end "98X" and it should say "For Laserjet 5" (and others). Take it up to the printer, open the box, take it out from the sealed bag (a penknife/teeth/etc are good for this), and locate the tag on one side which is to be removed. If you can't find the tag, read the instructions that came in the box. :-) Pull the tag out, which pulls out a long clear plastic strip. Throw it away. Now, lift the top lid of the photocopier from the front, like you're opening the bonnet of a car. (The display will read "Close cover"). Reach in and pull out the old toner cartridge, making careful note of its orientation, and replace it with the new one. It should "click" in and out - there's no real force required. Again, if it's not clear how things go, read the instructions. Close the cover, and you're set. Bag up the old toner cartridge into the new packaging and take it to the School Office for recycling.

In extremis (eg at a weekend when there's no access to the new toner cartridges) then a workaround is to take the old cartridge out and shake it up to extract the toner from all the nooks and crannies. Please note that this is quite likely to end up with toner all over you and your clothes (a minor issue) and all over the computers in H10a (far more important *grin*). So if you do it, be careful.

The printer is producing reams of largely blank pages with a few garbage characters on each.

You're (failing to) print a non-Postcript file on a Postscript printer. Cancel the print job (press the Job Cancel button on the printer!).

I need to abort a print job!

If there is a Job Cancel button on the printer, press it.  On the deskjet, this is the X button.  On the two HP laserjets, it's marked "Job Cancel".

Alternatively, take the Printer offline (by pressing the 'Online' or 'Go' button). Then use the lprm command to remove any part of the job still in the queue. Then switch the printer off, wait 30 seconds, and turn it on again to clear its memory. Do not turn it off without first taking it offline - you will cause a paper jam.

The deskjet printer is displaying an orange light and not printing.

Try pressing the large button on the front. This is sometimes because it thinks it needs a sheet of non-A4 size paper inserted, but pressing the button fools it into believing the next sheet (of A4) is fine for printing on.

Alternatively, you've told it to print from a paper tray that has no paper in.  Go back and resubmit to a paper tray with paper in, or put some paper in the paper tray.

The printer says "Remove Paper Jam" but there is no paper jam.

Is the paper tray very full? Try removing some of the paper in the tray, and open and close the cover to clear the message. If the error message is still there, turn the printer off at the power button, wait ten seconds, then turn it back on again. (You will probably have to resubmit your job)

The printer says "79 Service (06BF)"

Turn off the printer (with the button on the lower front), wait ten seconds, and turn it back on again. Print a self-test page (use the menu button to select the Test menu, use the options button to select "Print test page", and use the select button to print it). Does that print? No? Contact Dave Robson or Richard Balthazor, as it's likely to be an internal printer problem. Yes, the test page has printed? Good. Then it's likely to be a problem with the driver or the document. Try printing your document again. If it locks up again, repeat the above, then try printing from a different platform/route (eg Windows instead of Unix or vice versa). If all else fails, email the rogue document (or a pointer to it) to us, together with the exact print command/print options you used and what machine you used it on, so we can attempt to recreate and fix the problem.

Hardware Problems

My mouse is erratic.

If you have an optical Sun mouse (with the silvery metallic pad), has the pad been rotated ninety degrees? Rotate it back.

If you have a rollerball mouse: take out the ball (by rotating the retaining collar in the direction of the arrows) and wipe it off. Use tweezers/a knife/any suitable proddy thing to clean the fluff and gunge off the rollers inside the mouse, particularly the two orthogonal rollers; be careful with the spring-loaded roller because it is only lightly sprung and you might break it. Reassemble, and try to keep the mouse surface area cleaner!

If your rodent is totally deceased, Dave Robson and I have a stock of second-hand mice (although none have USB and very few have PS2 connections; most are the old D-style serial port connection). Alternatively CICS have new mice that can be purchased with cash or a purchase order number. Be sure to specify the connection:

• A USB connector is a flat black or silver rectangular connector a centimeter or so across and a few mm thick, used in the most recent mice.
• A PS2 connector is a circular male connector about 8mm across with six pins and one rectangular peg inside a circular skirt. These are found on most modern mice.
• A serial D-connector is a nine-pin female connector in a D-shape (one row of five, one row of four holes), often with two integral securing screws. These are found on older machines (486s and early Pentiums)

My keyboard layout is wrong.

(Commonly, my " and @ keys are swapped). Make sure you have selected the right language for your keyboard (Windows 98: Control Panel -> Keyboard -> Language). If you Add a language, it will prompt you for the Win 98 CD. If it fails to find the file it's looking for, you likely haven't enabled multilanguage support. Go to Control Panel -> Add/Remove Programs -> Windows Setup and click on Multilanguage Support, and OK your way through the windows until you can go back to the Language -> Add option.

If you add foreign language support to your computer, please be aware that I'm an insular Brit and thus can only read English (and, OK, a smattering of French), so please switch the language back to English before I take a look at it. :-)

How do I clean my keyboard?

Shut down and unplug your computer. Invert the keyboard over the desk and gently tap it. Ugh, yes. Clean that up first. Then get the can of Foam Cleaner / Anti-Static Foam Cleaner from the water cooler room, shake well, and give the keyboard (and mouse) a liberal spray. Let it foam up for a while, then wipe clean with a lint-free cloth. Use a scrubbing brush/nail brush on stubborn deposits. Use a blunt narrow thing, eg a broken plastic ruler or similar, to get the cloth between the keys. If there are bits of foam you can't get out, leave to dry naturally before you switch everything back on again. It is faintly possible that this may kill your keyboard, so don't do it an hour before an important deadline...

I'm getting an ACPI BIOS error...

AMLI: ACPI BIOS is attempting to read from an illegal IO port address
(0xXXX), which lies in the 0xYYY - 0xZZZ protected address range. This could
lead to system instability. Please contact your system vendor for technical
assistance.