Other features, such as shared network configuration for clients, remote client printing, centralized log files and a handy utility that lets clients send help requests to controls, make it suitable for the enterprise.

I tested both control (guest) and client (host) programs on Windows 98/NT workstations and NT/2000 servers connected to a LAN (IP/IPX). I also equipped one control and one client with 56-Kbps modems. The client program uses 3.6 MB of disk space, requires 3 MB to 4 MB of memory and loads from the system.ini in Windows 98 or runs as a service under Windows NT and 2000. The control program uses 11.7 MB of disk space and requires 3 MB of memory. PC Duo uses the underlying network transports and, new with 5.03, TAPI (Telephony Applications Programming Interface) support that recognizes modems installed under Windows. I didn't need to configure each PC manually to control it remotely via modem.

Improved Functionality

For sites that have multiple servers or clients requiring periodic monitoring, PC Duo has a useful scan operation that displays selected client PC screens one at a time in a dedicated window. To use it, I connected a control PC to each client needing monitoring and select "scan" from the tool menu. A dialogue box displayed the connected clients for the scan operation and let me choose a scan interval. If this tool could stop monitoring and focus on a problematic client based on an event or SNMP trigger, it would make an ideal sentry to monitor multiple servers from one console.

Helpdesks often use remote control to show users how to engage an application or perform a function. This proves futile, however, if the helpdesk is not familiar with the client desktop. It may be more efficient for helpdesk staffers to use their PCs as examples. PC Duo enables control PCs to display their screens to individual clients or to an entire group. When a control PC is connected to a client or group, a "show" icon on the task bar transmits the screen session to the connected clients. To end the session, support staff resumes a control session. This requires a control PC to install the client application.

With ActiveX, a control PC can engage a client running Microsoft Internet Explorer (IE) 4 or higher. No control software is required. I set up an ActiveX control on a client by using the advanced-options tab in the client configurator. In the configurator, I opened the master profile and selected the Web-extensions tab to enable ActiveX and set the root directory for HTTP access. After restarting, I connected with IE 5x. The client asked for a user name and password and, when satisfied, opened the desktop inside the browser, where I could view, share or control the client desktop. Unfortunately, I didn't have access to the same tools available in a Windows control, such as file transfer and remote-program execution.

PC Duo's screen transfers go beyond simple, bitmap image caching, providing fast screen refreshes. A GDI (Graphics Device Interface) hook on Win9x/NT machines captures standard Windows video intercepts sent to the video driver and forwards them to control PCs. On Windows 2000, PC Duo uses the Mirror Driver technology (dual-monitor support) to intercept video instructions. For added performance, this version introduces Video Skipping, a technology that examines video instructions already sent to the control PC; if the screen information is the same, the control redraws its screen using previous instructions. In earlier versions, all the instructions were sent.

Support staff needing client configuration information will find PC Duo's snapshot function indispensable. System Snapshot stems from Vector Networks' LANutil32, a PC management technology. This feature integrates the LANutil32 client with PC Duo and provides detailed hardware inventory information upon request by a control PC. Although the utility will not compare previous snapshots for changes in the environment, it includes info on CPU type, memory, OS version, network adapters and more. I would like to see this feature store inventory information on a server accessible to all control PCs.

Client PCs can be easily placed into groups on a control PC for organization and action. Operations performed on individual clients also can be applied to groups. A control PC can connect, distribute files, broadcast messages, execute applications and log off or reboot PCs associated with an entire group simultaneously. Control PCs can send files to multiple selected clients as well as groups. PC Duo includes a wizard that helps create groups.

Room for Improvement

Vector Networks has plans to deliver a version of PC Duo to support remote sessions in Navigator as well as IE. However, the ActiveX control needs more functionality than watching, sharing or controlling a remote client. Also, more LANutil32 functions would improve PC Duo and reduce the need for administrators to install and learn another management utility.

Sean Doherty works for Computing and Media Services at Syracuse University. Send your comments on this article to him at spdohert@syr.edu.