Long distance information transport through electronic networks may require substantial time due to slow transfer rates (0-5Kbyte/sec) but also to substantial waiting times between transport of subsequent data packages.
Forward and backward jumping between the addressed www-pages requires additional network data transport because the browser's caching capacities are limited by free hard disk space.
The installation of mirror sites, Off-Line Internet from harddisk or CD-ROM permit to downcut on waitings times.
- The Purdue E-mail box and archive mirror on the Martinsried site is a partial mirror i.e. the table of contents as the most consistent data package is mirrored while the shorter E-mail messages are localised at Purdue.