System Administration

This appendix is intended for any person responsible of maintaining the system hardware and installation. It describes various tasks that should periodically be done to ensure smooth operation of the system.

System Overview

The CAN-8 system is designed to operate in a client-server environment. The server software typically runs on Windows NT (workstation or server), Windows 2000 (workstation or server), Windows XP and windows 2003. using the Intel based platform. The client software may run on either Windows 95/98, Windows NT, Windows 2000 and Windows XP.

In order to operate, both the client and server machines must have TCP/IP loaded and properly configured. The server system may be placed behind a firewall if UDP ports 17180-17190 are left open to access the server or if the firewall is configured to redirect these packages from it's outside IP address to the CAN-8 server.

The CAN-8 server process provides its own security between client stations and itself. This includes login authentication, user management and enforcement of single logins. The CAN-8 server process may run either as a service process or an application on the server. The program does not display a window so there is no information to observe on the server itself. All information regarding users and operation of the system is accessed via the client station.

The CAN-8 server may run alongside other applications on the server machine, however care should be taken to ensure that the server has enough CPU power and memory to handle both. The server process will consume a maximum of 60 MBytes while running. Additional memory in the server will improve performance as it will be used as a disk cache by NT itself.

The client software may be provided as a compressed archive. The size of the software without the online manual is approximately 3.5 Mbytes. The online manual raises this size to 10.5 Mbytes.

System Backup

The system consists of regular files that are typically stored under the \SVSYS\... directory. While the server program is running, various files throughout this directory will be open for writing and reading. For backup purposes, the files may be read at any time as database and student tracking files are typically appended to and not modified in place.

The backup procedure used must be capable of reading files that are currently open for writing by another process. Also, the backup program must not ever open any file with write access as it will potentially prevent the server program from being able to write to the same file at the same time.

It is recommended that a full system backup be used rather than an incremental backup due to the large number of files that are modified during the operation of the system. Each incremental backup may be as large as the full system backup in this case.

Managing Disk Space

As a resource, the disk space on the server will be consumed by the system at a fairly high rate. The exact amount consumed will depend on the number of students performing recordings, the length of the recordings and the amount of static course material that has been recorded on the server. In most cases the student recordings will far exceed the space used by the course material, as well, the amount of course material does not increase constantly, where as the student recordings may do so.

The approximate disk space used by students for recordings may be calculated as follows for the purposes of example: 


Average minutes spent by students recording per session

  X

Number of students using system per day

  =

Total minutes of recording time per day
If you take this total and divide by 60 minutes to the hour and then multiply the number of hours 15 Mbytes you will have the daily total storage requirements for the system. For example: 

30 minutes per session recorded X 150 students per day = 450 minutes per day

450 minutes per day = 7 hrs per day  = 105 Mbytes per day

Assuming classes 5 days a week = 525 Mbytes per week

Per month = 2.1 GBytes per month

Per 4 month term = 8.4 Gbytes
As you can see, the amount of disk storage for students climbs rapidly.

In order to combat the eventual filling of the entire server disk, the instructors should be advised to remove students from the lesson tracker screens as soon as possible after they are finished scoring the work or have gone over it in class.

When the instructor deletes items from the tracker, the data is placed in a temporary recovery area where it may be archived or deleted by the system administrator. This area is to be found on the server in the directory \SVSYS\DELETED assuming the file directory layout of a standard installation.

After instructors have deleted the data from the Tracker screens, this directory may be deleted by the administrator to free up the disk space used by the student responses. This directory may be removed while the server is running.

System Cleanup

At the end of each term or year, it is sometimes desirable to remove all the students from the system. There are two methods of accomplishing this. Both methods rely on using the REFRESH option in an import student registration file. The two types have different effects:

REFRESH STUDENTS

This option removes all students from the system but leaves instructors, and their class names intact. This option is useful between terms for when it is not desired to re-create instructors or class names.

REFRESH ALL

This option removes all students, classes, assignments, and instructors. The MASTER user is remove and re-created with the default password of PWORD. This option is useful at year ends when instructors and class assignments will change. This option also has the side benefit cleaning up the users database file and re-compacting it.

In both of the above cases, the \SVSYS\DELETED directory should be removed to free the disk space that is used by student responses.

Starting and Stopping the Server

The CAN-8 server process may run as an application or service on the NT machine that is being used as the server. In this case it is generally automatically started when the server is started or when the administrator user signs on. In some cases, it may be required to stop the server process and then re-start it. These cases are:
In order to shut the server process down if it is running as a service (does not show in taskbar), the following steps are required:
  1. Go to the NT control panel.
  2. Double click on Services.
  3. Scroll down to CAN-8 Server.
  4. Press the Stop button.
  5. The service manager will notify you when it has stopped running.

If the server process does appear on the taskbar, then use the following steps:
  1. Click on the minimized taskbar box for the server, a large empty window will appear on the screen.
  2. Click on the X in the upper right corner of the window, if you are running a version with debugging code included, a box will appear in the centre of the screen that asks if you wish to create a system dump upon termination. Select NO unless advised otherwise.
  3. The empty window will disappear indicating the server process has stopped.

Once stopped the system may safely be modified. Modifying the system files with the server process running may result in damaged files.

To restart the server process if it is a service, these steps should be followed:
  1. Go to the NT control panel.
  2. Double click on Services.
  3. Scroll down to the CAN-8 Server.
  4. Press the Start button.
  5. Exit the service manager when the CAN-8 server has started.
In the case that the server application is started on the login of the administrator user, it may be simply re-started by double clicking on the CAN-8 icon on the desktop.

System Reporting/Monitoring

While operating the system tracks various internal parameters in a file called SERVER.LOG that is created in the same directory as the NTSERVE.EXE program. This file can be examined to monitor the system operation. This file must not be opened for write access while the NTSERVE program is running as it will cause the NTSERVE program to wait until exclusive write access is available.

This file is updated approximately every 10 minutes when the system is idle and more often during periods of heavy use.

If problems are encountered with the operation of the NTSERVE program, it is wise to make a copy of this file for examination later.

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