Answers to Common DoubleVision Pro Questions

Yes, DoubleVision works equally well with ttys and pseudo ttys.

When the host and remote terminals are identical, the terminal type is not a factor. In reality, however, users usually do not have the same type of terminal. One of the greatest features of DoubleVision is its ability to allow a remote user with one type of terminal to attach to and view a host user who has a different type of terminal. DoubleVision supports over 90 terminal types, including all common ones.

This is a very important issue since screen and keyboard types are not standardized in the UNIX environment. DoubleVision uses a process called terminal translation to interpret and translate the command language of the host terminal to the command language of the remote terminal. This unique terminal translation capability adapts to each terminal environment automatically and screen reformatting is handled on the fly.

There is nothing more frustrating than playing 20 questions with a user as they try to describe an error. And with DoubleVision you don’t have to. Our TrueScreenTM screen tracking module tracks and displays the host screen’s attributes upon viewing. This means that the remote user’s screen looks exactly like the host’s screen from the moment of first viewing — complete with screen attributes such as bold, reverse screen printing, etc. No “catch up” time is needed. TrueScreen is not hardware specific and works with any supported terminal type.

In the UNIX environment, the access you are permitted depends solely on what type of user you are. Root users are granted unlimited access to every aspect of the system, while all others are only allowed access if prior permission has been granted. DoubleVision uses this same user-level approach to security. The root user has no security constraints and can attach to any user or terminal at any time. All other users must adhere to strict rules governing terminal access. If any of the access rules are violated, the user is returned to the DoubleVision screen and a security breach error is displayed. No user (other than the root user) can view your terminal without your prior permission.

When a remote user is viewing your screen, DoubleVision’s security will signal you with an audible “beep.” This beep occurs every 20 seconds by default. Normal users may modify the time interval of the beep from five to 30 seconds, but can not turn it off. The root user may set this interval to 0, eliminating the beep, or from five to 30 seconds.

Preattaching (attaching to a host terminal before the user logs in) automatically turns on the TrueScreenTM and Instant Replay options. As soon as the host user logs in, information starts accumulating in a buffer. This ensures you have the entire terminal information available to effectively troubleshoot a user’s problem. If the remote user has not preattached to the host user, these features will be activated from the point of attachment forward.

Preattached has minimal impact on user performance. Only 2%-5%, depending on the application.

How many times has a user called saying they received an error message, but it was no longer on the screen and they couldn’t remember what it said? With Instant Replay you can play back any number of screens of user activity. Not only can you find out what the error message said, but also what keys they pressed to cause it. Do you have a phantom problem – a glitch that you just can’t pin down? Use DoubleVision’s recording capability to record and play back user sessions as easily as programming a VCR. Find out for sure if human error or a program bug is causing your problem.

To reap the full benefits of Instant Replay, the host user must be preattached. Each recorded screen takes up about 4K of disk space.

Yes, multiple users may view the same terminal at the same time. In fact, this remote training setup is used by many of our satisfied customers to eliminate travel time and slash expenses involved with traditional classroom settings. To find out how others have set up their portable classroom, click here.