Networking TWL CD-ROM Training Units

Overview
This document is designed to give you the basic guidelines for running TWL courseware from a network file server. This information is generic in nature and may not necessarily apply to all network configurations. The network administrator at your site is best equipped determine whether multimedia training applications, such as TWL’s, can be run across your company network.

The Course Management System
The TWL Course Management System (or CMS) was designed from the ground up to run in a LAN environment. The CMS is based on Microsoft’s FoxPro database engine and uses optimization wherever possible. Please refer to the Networking the TWL Course Management System document for specific information on networking the CMS. 

The ability to launch training content from the network is included with CMS versions 1.4 and later. By default, the CMS will only allow one workstation to view content stored on the file server. Concurrent access (of CD-ROMs installed to the server) requires a multi-user license. This must be obtained through your TWL sales representative.

Multimedia CD-ROMs
TWL multimedia CD-ROMs use extensive graphics, digital audio (wav), and digital video (MPEG) to present the training content. This makes a highly effective presentation. It also makes it a high bandwidth application. The presentation of high quality sound and video requires a large amount of data be fed to the computer from the source. Generally, the source is a CD-ROM drive. More frequently, customers are looking to install and run the material from a file server. 

A file server installation has several distinct advantages: 

• Once installed, the CD-ROM is filed away where it will not be handled or damaged.
• Any trainee can access any unit that is installed to the server at any time.

On the other hand, a file server installation has several hurdles to overcome:

• Each training unit must be copied to the file server’s hard drive.
• The large amount of data being moved requires a fast network.
• The network traffic caused by the CD-ROM training can adversely impact other network users.
• The network traffic caused by other users (day to day operations) can adversely impact the CD-ROM training.
• Multiple copies of a CD-ROM are often less expensive than a network license.

Resources Needed to Network the Training Material:

• File Server Hard Disk Space:
  To network the training material the entire contents of the CD-ROM must be copied to the file server’s hard disk. TWL does not support the use of shared CD-ROM drives on the network. 
  
  TWL training units usually occupy between 450 and 550 megabytes per unit for the Maintenance and Operations courses. The Safety course is generally 250 megabytes per unit. Installing several units to the network can require a substantial amount of file server hard disk space.
  
  
• Drive Letter Mapping:
  The CD-ROM units must be installed to the server and accessed via a mapped drive letter. UNC codes are not supported by the CD-ROM units. Different units may be installed to different network drives, but the drive mapping must remain consistent for all workstations accessing the units from the network.
  
  
• Network Bandwidth: 
  TWL multimedia CD-ROM units were originally designed to be run on a quad speed (4X) CD-ROM drive. This equates to about 600 kilobytes per second, which, in turn, translates on a network to around 4.8 Megabits per second. We have found that the material actually requires around 2 to 2.5 Megabits per second to run properly. That means that each trainee running a unit off the network will be using over 2 Megabits per second of your network’s capacity. For this reason, we strongly suggest a 100 megabit network. 
  
  TWL courseware makes extensive use of MPEG digital video. This video requires a constant data stream of around 1.5 Megabits per second. Conventional file servers were not designed to ensure constant data streams. Interruptions in the data can cause jerky, or stuttering video playback. There are companies that produce dedicated video servers that were designed to feed a constant stream of data to the workstations. PWPL has tested up to six workstations running different units concurrently on a standard Windows NT (3.51) server and noted no audio or video degradation. 
  
  For Ethernet networks, network efficiency degrades substantially as utilization (the amount of network capacity in use / the total capacity) reaches 50% and above. Note that unless you are utilizing a separate training network, you will be sharing the network capacity with other users.
  

Installing the CD-ROM to a file server
The CD-ROM units must be installed to the file server from a workstation. You can not install the unit to the server from the server itself. The unit must be installed to the mapped drive from which it will be later accessed.

Suggestions

• If your network is less than a 100 megabit network, run the material from a CD-ROM drive on the local workstation.
  
• Segregate training to its own network to minimize the impact from other users. If this is not possible, schedule training during off-peak hours.
  
• If you are planning to network more than few users concurrently (more than 6-10), consider purchasing a video server. These servers are designed to maintain the constant data stream that digital video requires.
  
• Contact your TWL salesperson if you are interested in networking the training material. They will discuss aspects of licensing and other network issues. When appropriate, they can arrange for a trial network license for evaluation purposes.

Conclusion
Running any multimedia title off a file server can be a technically challenging task. It is important to remember that the network resources are finite. The network administrator will be able to assist you in determining if networking the courseware is appropriate for your particular site.