1. Synchronizing Clipboards of Multiple Computers Rob Miller Brad Myers School of Computer Science Carnegie Mellon University UIST ‘99November 7-10, 1999

2. One User, Many Computers Desktops Laptops PDAs Cell phones Pagers Car PCs Live Boards... Windows Unix/X Macintosh Palm Windows CE... How do I move data between programs running on different computers? URLs Email addresses Phone numbers Text Files

3. Inter-Application Data Transfer Same Computer Filesystem Drag-and-drop Clipboard Different Computers Network filesystem Pick-and-drop [Rekimoto, UIST 97] Hyperdragging [Rekimoto, CHI 99] Synchronized clipboards

4. Synchronized Clipboards Key idea: synchronize the clipboards so that their contents are always identical. User’s clipboard group consists of all computers in active personal use (ideally).

5. Advantages Cut/copy/paste is a familiar, universal UI –All popular GUIs have a clipboard –No extra hardware is required Synchronization is invisible –User doesn’t need to explicitly name source or target computer in each data transfer (unlike other “network clipboards”)

6. Limitations Best for one user only –Two users can’t actively share a synchronized clipboard Computers must be in close proximity –Unsuitable for long-range transfers

7. Model #1: Client-Server Client Server Client Network traffic on all client clipboard operations Client clipboards must be interceptable XX

8. Model #2: Peer-to-Peer A A B C No network traffic for local clipboard operations Clipboards must allow delayed data transfer Peer A

9. Prototype Uses Both Models PalmPilot: client-server –Palm clients connected to server PC by serial cable or cradle Windows, Unix/X: peer-to-peer –Java/RMI across the network Both models interoperate –Just hook up server as a peer

10. Setting Up Clipboard Group PalmPilot: plug/unplug Palm in cradle –Clipboard group connection is automatic Windows, Unix: add/remove hostnames –Automatic discovery (e.g. Jini) would help My clipboard group should contain all devices I’m actively using –But perfect tracking is tricky

11. Security Authentication by popup dialog SSL, Kerberos, PGP, … would help –But all require some infrastructure: trusted authorities, key management, etc.

12. Conclusion Synchronized clipboards extend the familiar clipboard model for seamless data transfer between computers Prototype (for Palm, Windows, Unix) is available at: http://www.cs.cmu.edu/~rcm/RemoteClip/