The Tie That Binds

Microcomputer to mainframe and micro to mini communications are hot topics today -- with good reason. For many growing companies, these links could provide a competitive edge.

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As senior analyst for InfoCorp, a $2-million-a-year microcomputer market research firm in Cupertino, Calif., John Kiefer keeps close tabs on companies that are working to connect mainframes and minicomputers with micros. In the past few months, however, Kiefer's interest in the subject has become more than academic. That is because the linking of InfoCorp's IBM System/38 minicomputer with an IBM Personal Computer has made his own work easier.

The advantages of linking big and little computers are obvious. Mainframes or minis store the data that comprise the entire historical record of a company. But, says Esther Dyson, president of Rosen Research Inc. in New York City and editor-in-chief of a microcomputer newsletter, RELease 1.0, while larger computers are very good for number crunching, they are not very good for interactive processing. Mainframe software provides reports and does batch work. On [personal computers], typically, you don't get reports, you get answers." Besides, running application programs on big machines is far more expensive and complicated than on micros.

InfoCorp's analysts knew all about the advantages of personal computers. But at the time that the company bought its $150,000 System/38, there was no way to connect it to micros. And the company's needs dictated that it buy the larger machine. Since InfoCorp is in the information business, it has significant amounts of data to store, more than a micro -- even one equipped with a hard disk -- could handle. And very sophisticated software is required to manipulate that information. Predictably, however, the decision to go with the mini made life difficult for employees at first.

With the 10 terminals InfoCorp rented for the System/38, analysts could call up information and display it; they could also use the mini's software to analyze the data. But there were two problems.

First, although the mini had a spreadsheet program, it was, says Kiefer, "horrendous." Products like Lotus 1-2-3 or VisiCalc, which run on micros, are, he says, "an order of magnitude superior." Designed for nonprogrammers, they are far easier to use and more efficient analytic tools. Second, there was no graphics software. "We do nothing but pie charts, bar charts, and line charts all day long," he says. "It's a real pain in the neck to strip the data off the [mini] and plot it out by hand." Kiefer's solution was to bring in his own IBM PC. He then had two terminals on his desk -- one to collect the data from the mini, the other to manipulate it in a form he could use.

Then IBM came out with software and a board, for $893, that could be inserted in the PC to make it emulate, or act like, a terminal. Now Kiefer can collect data from the mini and use Lotus 1-2-3 on the micro to analyze it. And he can quickly create graphs. "We get the data into 1-2-3, manipulate it, punch a button, and out comes the chart. That saves us significant amounts of time," he says.

A portion of the mini's storage capacity can also act as a virtual diskette: The System/38 looks to the PC like a big disk drive and can store work done on the micro. So company analysts can collect their own information and put it in centralized data files. Or an analyst can build a model, walk to the next office, and have another analyst look at it on his or her own PC. The advantages of the PC linked to the mini are so great, in fact, that in the next few months, InfoCorp plans to replace many of its terminals with micros.

InfoCorp's connection, however, is not the most sophisticated possible. With a "smarter" terminal, the mini's data could be converted automatically into a form that Lotus 1-2-3 -- or another application package -- could recognize. So, with a simple command or two, Kiefer could transfer his information directly into the spreadsheet. With Kiefer's "smart" terminal, he can receive information from the larger computer and process it locally. But when he works with 1-2-3, he must save the data he receives from the System/38 in memory, edit it, then key it into the Lotus spreadsheet.

A micro can also be linked to a mainframe or mini as a "dumb" terminal: The machine can display data, which a user can manipulate with the mainframe or mini software, but the micro cannot store or process information from the mainframe on its own.

Making a connection work is not always simple, primarily because large computers and micros use many different protocols, as if they were speaking different languages. Two machines can be linked either directly with cable -- "hard wired" -- or via telephone through a modem. One common problem arises from the different schemes -- or communication protocals -- by which large and small computers code the information, or bits, that they send over the wires: IBM mainframes generally use what is known as synchronous or bisynchronous communication; micros, usually asynchronous. So the first step is to make one machine use the other's signal schemes. Generally, a piece of hardware provides the physical link and converts one type of signal into the other.

But even a dumb terminal requires simple software to tell the machine what to do with the signals it receives. For instance, without software, a terminal will not understand that a certain character should appear on the upper left-hand or on the lower right-hand corner of the screen. A terminal may need additional software to change EBCDIC, a common way characters are coded in IBM mainframe files, to ASCII, the standard coding for microcomputer files. And, a smart terminal must have programs that let it store data on its own disks and move files from those disks to the mainframe.

Finally, application programs, such as 1-2-3 or VisiCalc, store files in different formats; in effect, they organize their in formation differently. If mainframe or mini data is to go directly into these programs, an additional layer of software is required to reformat data into a form that 1-2-3, for instance, can recognize and accept.

The ability to tap into public databases, such as Dow Jones News/Retrieval Service or The Source, is now commonplace. VisiCorp, in San Jose, Calif., provides a useful variation on this kind of connection. For $250, VisiLink software gives microcomputer users access to Data Resources Inc., a business and financial information database provider based in Lexington, Mass. Users select the data they want -- details on a particular company, perhaps, or foreign exchange rates -- pay for just that data, and receive it in a VisiCalc template, complete with formulas and labels. They then can add information about their own company to do forecasting or make other analyses. Lotus Development Corp. in Cambridge, Mass., has announced similar arrangements with ADP Network Services in Ann Arbor, Mich.

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