Computer Designation for C.A.R.L. V4

C.A.R.L. can run standalone, or in a networked multi-user environment.

Single Computer

If you wish to run C.A.R.L. on a standalone computer (e.g. a laptop) totally self-contained, then you can select the “Standalone” designation of the compatibility checker.

Because standalone computers have the C.A.R.L. databases on their local hard disc, there are no worries about having to handle network traffic while maintaining the database.

This also means that even computers with low specification processors, even some home machines with Celeron processors, can run C.A.R.L.

Multiple Computers

C.A.R.L. can work in multi-user environments in 2 different ways.

It can run under “Terminal Services” (recommended), or the older method called “UNC” (not recommended for larger databases / loaded networks).

Terminal Services was originally only available on very expensive top-end servers; however nowadays it is within the grasp of anyone with a Windows XP Professional PC.

A 3^rd party product known as “XP Unlimited Classic” has taken the market by storm, as it allows cheap XP PCs on a workgroup to become very good servers for around $125 (approx £70 at time of writing).

There is also a Domain version available for larger companies.

A free 3-user version of this can be found at www.xpunlimited.com in the “Demo” section.

Please note: C.A.R.L. Communications has no financial connection with XP Unlimited. We mention XP Unlimited here simply because so many of our customers have benefited from its use!

Terminal Services can also be purchased from Microsoft for Server 2000 or Server 2003 Operating Systems (excluding the restricted Small Business System Operating Systems).

When a Terminal Services server hosts the C.A.R.L. databases locally, the benefits are outstanding – Each slave PC is considerably faster than the old UNC method (almost as fast as the master in fact) and the risk of database corruption due to intermittent network problems disappears.

With Terminal Services, there are 2 designations.

Terminal Services Master

As the name implies, this handles all of the requests to run C.A.R.L. from each Terminal Services Slave.

A user account is created for each Terminal Services slave on this master.

C.A.R.L. is installed on this computer as a ‘Master’.

Where possible the databases are also stored on this computer, to remove the risk of database network corruption.

Terminal Services Slave

This is the designation for the other computers that connect to the Terminal Services Master.

C.A.R.L. does not have to be installed on the slave itself, simply a desktop shortcut is created to the account on the master.

Terminal Services slaves can be low specification, because the work is done on the Terminal Services Master.

No conflict of exising software on the slave is a worry, again because all of the work is done by the Terminal Services Master.

Terminal Services is also good way to use C.A.R.L. remotely over the internet / VPN.

UNC is the older method, which is still acceptable for sharing word documents, photos and light-moderate usage on shared drives.

However, It is not recommended for real-time database updating unless you have extremely powerful computers, or very light network usage and small databases.

For this reason, we recommend that you upgrade to Terminal Services rather than using the UNC method.

With UNC, there are 3 different types of designation:

Dedicated Fileserver

This is a computer (or NAS) that simply holds the databases and handles the read/write data requests from the UNC Slaves.

The keyboard is not used, nor are other programs running while it is acting as a Fileserver.

The C.A.R.L. data resides on this server; The C.A.R.L. program does not have to be installed.

Interactive Master

This is the same as a UNC Fileserver, except that the C.A.R.L. program is installed and is used interactively while also handling read/write data requests from UNC Slaves.

Interactive Master computers need to be very powerful as they’re being interrupted by network traffic while reading/writing data to the databases.

There is the potential for database corruption with this method.

UNC Slave

These connect to either Interactive Master or Dedicated Fileserver computers.

UNC Slaves need to have good network cards and fast processors, otherwise data that should be written to the UNC Master will be delayed, which can result in database corruption.

Please see here for more information on Terminal Services vs UNC.

In conclusion: Terminal Services is the preferred method over the older UNC method, due to the increases in performance and data integrity.