3. Step 2 - Narrow Down the Problem

The next step in diagnosing a problem is to try and narrow down the location of the problem and the context in which it occurs. For example it may only happen with a particular program, or with a particular user, or when processing a certain document, or at a particular location or at a certain time of day. Examples of narrowing down the problem in some common scenarios are illustrated below.

3.1. Scenario A - A Printing Problem

You can't access your printer - does the fault lie in the computer or the printer or the cable in between?

  • Does a different cable (preferably one know to work elsewhere) fix the problem?

    • YES - your original cable was faulty or not connected properly.

    • NO - then...

  • Does the printer work with a different computer?

    • YES - the problem is probably within the computer

    • NO - the problem is probably within the printer.

  • Does a similar printer work with your own computer (using the same printer driver)?

    • YES - the problem is probably with the original printer

    • NO -  the problem is probably within the computer.

If the problem seems to be within the computer:

  • Is the problem confined to just one application?

    • YES - the problem is with the installation/configuration of that particular program.

    • NO - then...

  • On a PC Windows system, is printing possible from the MS-DOS command prompt (e.g. via a command such as: COPY C:\AUTOEXEC.BAT LPT1: )?

    • YES -  the hardware is OK and the problem may be in Windows printer-driver installation/configuration.

    • NO - there may be a problem with the computer's printer port.

If the problem seems to be with the printer:

  • Does it print its internal test page?

    • YES - there may be a fault with the printer's communication port

    • NO - the printer may have its paper/ink/toner incorrectly inserted or may have more serious internal problems.

3.2. Scenario B - A Communications Problem

You are running Netscape Communicator on a workstation connected to a college ethernet socket. You can't access a particular web page, for example one at a site in the United States. The problem could be in:

  • Netscape Communicator installation/configuration

  • Workstation's communication software installation/configuration

  • Workstation's communication hardware

  • Cabling between workstation and local network point

  • Cabling between local network point and network hub

  • Communications link between local college/departmental network and local central network

  • Communications link between local central network and external UK national network

  • Communications link between UK national network and US national network

  • Communications link between US national network and remote US site

  • The server at the remote US site

Although some of these factors are clearly outside your control, it should still be possible to narrow down the problem. For example:

  • Can you access other US sites successfully, e.g. http://lcweb.loc.gov/

    • YES - the problem is at the remote site

    • NO - then...

  • Can you access any UK sites, e.g. http://www.bbc.co.uk/

    • YES - the problem may be with the transatlantic link (or with the web-cache if you have a Netscape proxy configured for non-UK sites)

    • NO - then...

  • Can you access any local sites, e.g. http://www.ox.ac.uk

    • YES - the problem may be with the link between the local central network and the UK national network.

    • NO - then...

  • Can you access any sites within your department, e.g. a departmental web server? If you have Windows 95/98/NT, can you browse the Network neighbourhood and see other local machines listed?

    • YES - the problem may be with the link between your college/departmental network and the local central network.

    • NO - then...

  • Can you successfully use other communications such as Telnet, FTP, or a different web browser.

    • YES - the problem may be a Netscape configuration setting

    • NO then...

  • Does your machine work if you use a different cable or network socket which are known to be OK?

    • YES - you have a faulty cable or network socket.

    • NO - then the problem is probably with your communications software installation or configuration. How you proceed from here depends on what type of system you have. For example...

  • If you have Windows 95/98/NT, does the System Control Panel's Device Manager entry for your network adapter report a problem?

    • YES - there is a problem with your network adapter.

    • NO - then...

  • Does the Network Control Panel have a TCPIP protocol entry and are its properties configured correctly?

    • NO - Add a TCPIP entry and configure its properties using the address information obtained from your unit's IT Officer.

    • YES - then...

  • Use the Start/Run option and enter the command: WINIPCFG - does this display all your address information correctly?

    • NO - there is a problem in your TCPIP configuration. You could try removing the TCPIP entry from the Network Control Panel and re-adding/re-configuring it.

    • YES - seek help!

3.3. Scenario C - An Email Problem

If you have a problem using your email client, the fault could be in your workstation's email client configuration, or in its general communications setup, or with your account on the remote mail host, or even a general problem with the mail host itself.

  • Do other communications programs such as Netscape or Internet Explorer work?

    • NO - you probably have a general communications problem.

      • If you are connected to the campus ethernet system, see the last 4 steps of the previous section.

      • If you are a dial-up user, check your dial-up configuration. If you have a new or recently changed password, your dial-up configuration may need updating to include this information.

    • YES - then..

  • Is the problem only with sending mail?

    • YES - then...

      • check the SMTP host on your email client's configuration screens - set it to smtp.ox.ac.uk

      • check your own email address on your email client's configuration screen. It should be of the form: firstname.secondname@unit.ox.ac.uk e.g. John.Smith@oucs.ox.ac.uk - it must not contain spaces, accented characters etc. If your client allows you to define a "Return address" this should normally be left blank.

      • Check the recipient's email address carefully. Try sending a message to yourself.

      • Check your time-zone is set correctly - on Macs, use the Map control panel; on Windows 3.x add the line SET TZ=GMT0BST to your AUTOEXEC.BAT file.

    • NO - then...

  • Is there a problem with both sending AND receiving mail?

    • YES - then...

      • Check your mail-host and SMTP entries on your mail client's configuration screen.

      • Check the status

        of your mail host.

    • NO - then...

  • Is the problem only with receiving mail?

    • NO - then your problem is outside the scope of this example.

    • YES - then...

  • Is your email account name correctly entered on your email client's configuration screens? Your account name (e.g. cher0123) is quite different from your email address (e.g. John.Smith@oucs.ox.ac.uk).

    • NO - then enter your correct email account name.

    • YES - then...

  • Does your email account have a new or recently changed password?

    • YES - if your email client stores your email account's password, check that its configuration has been updated to use the new password.

    • NO - then...

  • Is your account over quota? You may have received an email message from OUCS informing you about this.

  • Is your mail host machine running normally? (Check the OUCS "System Status" web page.)

    • NO - wait for the host problem to be resolved.

    • YES - then...

3.4. Scenario D - Erratic Freezing, Hanging, Crashing and Bombing

Freezing, hanging, crashing and bombing are all terms that people use to describe a computer that suddenly stops working while in use. These terms are not totally consistent in how they are used but broadly speaking:
  • Freezing

    - usually describes a system that has suddenly become completely inactive whilst running. There are no error messages on the screen, the mouse pointer does not move, and pressing keys has no effect whatsoever - not even producing beeps etc.

  • Hanging

    - usually describes a less severe form of freezing. Things have ground to a halt, there are no error messages, but the machine is not completely dead. The mouse pointer may still move and, on a PC system, pressing the Ctrl/Alt/Del key combination produces a response.

  • Crashing

    - usually describes a situation where a program has terminated abnormally, often with some kind of error message. The machine may still be usable.

  • Bombing

    - the Macintosh equivalent of hanging/crashing. A message (accompanied by a picture of a bomb!) appears. Usually the system needs restarting.

Freezing is usually symptomatic of a hardware fault, or of a non-Plug-and-Play device that is internally misconfigured. If it occurs erratically, the problem may be due to a component that fails when it gets warm after the machine has been in use for a little while. If you turn the machine off and let it cool down, it may work normally for a while. Keep a log of its behaviour and how soon after switch on it misbehaves.

Hanging, crashing and bombing are generally more likely to have other causes which can be investigated further. If you suffer from these, then note whether the problem always occurs at precisely the same point, or only with certain documents, or only after having run certain other software etc.

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