 IBM saw satellites as the way of the future. It invested in Satellite Business Systems (SBS), hoping to bypass the Bell System monopoly with direct-to-the-business satellite service. The delays inherent in geosynchronous satellites were harmful to bisync. This gave them an impetus to develop a new protocol suite, called Systems Network Architecture (SNA). Although SNA eventually had some host-to-host connectivity, it was primarily designed for remote block-mode terminals. Large corporations built worldwide SNA networks, primarily to connect desktop terminals to large mainframes. It remained popular until terminals themselves were replaced by desktop comput- ers in the 1990s. Indeed the IBM mainframe world had its own sort-of-version of the Inter- net. Bitnet (whose name allegedly meant "because it's there") interconnected numerous universities beginning in 1981. Although not a packet-switched net- work, Bitnet used store-and-forward techniques said to be based on punch-card images. It was used for electronic mail and mailing lists. It grew to more than 500 organizations and 3,000 nodes (hosts) by 1989, but by 1994 most of its users had migrated to the TCP/IP-based Internet [5]. A closer analog to the Internet was Digital Equipment Corporation's DECnet. Begun in the 1970s as a way to interconnect the company's minicomputers, DECnet became a popu- lar networking technology in the 1980s. It was very similar to TCP/IP; indeed, many of the same individuals worked on both. DECnet was not, however, designed for inter-company communications. Its most popular version, Phase IV, was limited to a 16-bit address field and 6-character host names. Within the DEC computing world, though, DECnet had many interesting capabilities; applications could often open files on any other computer on the same network just by prepending the host name and the characteristic double colon to the file name. Rather weak on terminal to host support, it eventually had Internet mail and file transfer gateways. DECnet's design center and function s