As personal computers become more sophisticated, they take on more tasks previously handled only by minicomputers and mainframes. But personal computers hardly are driving those machines into extinction.
In fact, organizations that rely on large data processing systems are finding ways to connect their various kinds of computers. The goal is to pair the personal computers' low cost, flexibility and ease of use with the bigger computers' ability to run powerful software, handle enormous amounts of information and link users throughout the world.
That trend hasn't been lost on Digital Equipment Corp., a leading maker of minicomputers that has had only limited success with its personal computers. For years, many people have connected Apple Macintosh personal computers to Digital's line of Vax minicomputers and mainframes. Rather than fight the trend, Digital has decided to encourage it.
On Jan. 15, Apple President John Sculley and Digital President Kenneth H. Olsen announced that their companies entered into a "joint development effort." No specific products were mentioned, but the agreement clearly is designed to ease communications between the Macintosh and Vax machines.
Vaxes, which are are popular with academic institutions and companies involved in engineering and scientific research, often serve as the heart of "multi-user" systems. Anywhere from two to hundreds of people work simultaneously on such a system, sharing databases and access to the central machine's processing power.
Sculley said about 36% of Vax users also have Macintoshes, and in half of those cases, at least some Macs already are connected to the Vax. Occasionally, the link is made over ordinary telephone lines. Increasingly, though, the machines are linked by a cable in what is known as a local area network. In most cases, it also is possible to connect other computers, including IBM PCs, to such networks.
Several companies, including Alisa Systems of Pasadena and Kinetics of Walnut Creek, Calif., already make products designed to enable Macs and Vaxes to communicate with each other. Kinetics makes connectors for the two machines, and Alisa manufactures software that allows them to exchange information.
There are three levels of communication that a personal computer can have with a Vax or another "host" system. At the most basic level, the personal computer can be used simply as a terminal. There are a number of programs designed to make a Mac or an IBM PC act like a Digital terminal. Likewise, there are programs that let Macs and PCs mimic terminals for IBM mainframes. A more sophisticated type of linkup allows the host computer to act as if it were a giant disk drive, or data storage device, for the personal computer. For instance, files on the Vax can be stored or accessed by the Mac just as if they were on the Mac's hard disk. That makes it possible for the Mac and Vax to share data as long as the programs on both machines can read the same files.
The most sophisticated linkup enables the software on one machine to interact with the software on another. Alisa Systems makes software for that purpose.
For example, it has an experimental Macintosh program that displays pictures of automobile parts. To find information about a specific part, you point to it with the Apple's mouse and click its button. The Mac then sends a query to the database running on the Vax, which sends back information about price and availability. That information, in turn, is graphically displayed on the Mac. To place an order, you click a button on the Mac's screen and it passes the information directly to the Vax's order processing software.
The agreement between Digital and Apple serves as an endorsement of the type of work being done by Kinetics and Alisa. Some of Digital's institutional customers needed that assurance before investing in Macintoshes and the equipment and software to connect them to the Vax.
The initials IBM were conspicuously absent from the announcement. Many industry watchers believe that the Digital-Apple agreement is designed specifically to help the two companies compete against IBM. (All the same, Apple is committed to giving its computers the ability to communicate with IBM mainframes. On Monday, Apple announced new products for that purpose.) Digital is IBM's leading competitor in the minicomputer field, while the Apple Macintosh is increasingly perceived as a serious alternative to IBM's personal computers for large corporate customers.
Efforts to stitch together networks of large and small computers may get a boost from a venture being undertaken by two of the leading makers of personal computer software.
Microsoft and Ashton-Tate have teamed to develop high-end database management software to run under Microsoft's new OS/2 operating system. The aim is to equip networks of personal computers with the same type of database management software now used by many minicomputers and mainframes.