The personal-computer spectrum has a strong shade of Big Blue; In the market for just two years, IBM has pioneered a standard with its PC

Paint the personal-computer picture by number, and most of the canvas comes out blue -- Big Blue -- for IBM. Until two years ago, the small-computer industry was untinted by the computer giant's presence. But when IBM entered the market with its Personal Computer, it did so at a critical time. The microcomputer industry had a major problem: lack of meaningful standards.

Most of the machines on the market were incompatible. They would not run the same programs. They stored their data in different formats. They used a number of different operating systems -- the basic programs that control communication to all the basic components in a computer system.

When prices of computer systems were $15,000 or more, standardization wasn't so important. Software tended to be customized for the specific needs of each client. But as costs dropped below $10,000, the basic nature of the market began to change. It became more consumer oriented. And "the closer a market is to the consumer level, the more important standards are," observes Portia Isaacson of Future Computing, an industry analysis firm.

A key in establishing the PC as a standard was IBM's decision to publish details of its hardware and technical specifications for its machine. This made it possible for independent companies to develop both hardware and software that would work with the PC.

The allure of writing for Big Blue generated a software industry stampede to the PC. Of the 1,200 companies writing software before the IBM machine was introduced, more than 900 are now writing for the PC. Some 50 new software packages are being introduced for the PC monthly.

According to IBM-watchers, the success of their microcomputer caught even IBM officials by surprise. Not only did they rapidly capture 40 percent of the market for desktop computers in the $2,000-to-$5,000 range, but the PC fast became the de facto standard for the entire industry. (Some industry analysts now believe IBM will extend its dominance to the home-computer market with its recently introduced PCjr.)

The IBM PC prompted dozens of other manufacturers to turn out machines with the capability to run at least some of the software written for the IBM machine. The first of these work-alikes was produced by a Maryland company, Columbia Data Systems. Jumping so early on the IBM bandwagon, its president, William Diaz, recalls, has resulted in growth "far beyond our wildest expectations." In a year and a half, Columbia has shipped more than 20,000 computers.

While machines with the greatest degree of IBM compatibility have been doing well, a number of computers without this advantage have suffered. Even Apple, IBM's archrival in the microcomputer arena, has recently announced a tox that will allow the Apple II computer to run much of the software for the IBM.

IBM-watching, a well-established practice in the mainframe computer industry, has become rampant in the microcomputer business. At the recent Comdex trade show, speculation about IBM's intentions dominated most conversations. The central issue is whether IBM will continue its policy of openness or whether it will try to return to the secrecy that marks its actions in large computers.

Jean Yates, an industry consultant, argues that IBM will move gradually into a proprietary operating system, connecting its top-of-the-line PCs with its big computers. Such a system, she speculates, will allow these computers to run all the popular PC software but will have proprietary features that will freeze out independent software houses.

Dr. Robert S. Harp of Corona Data Systems, which makes a line of IBM-compatible machines, says next summer IBM will introduce a new machine more powerful than the PC. He says this will run a modified version of a proprietary , IBM mainframe operating system and will also be able to run programs written for the PC.

It is now the software companies that have the greatest vested interest in the PC standard, Future Computing's Mrs. Isaacson points out. According to Bill Godbout, an industry veteran who once worked for Big Blue, even IBM has found itself trapped, at least a little bit, by the success of the PC.

"There will be standards," Mrs. Isaacson asserts. "IBM can choose to lead, counter, or follow them." Even if IBM goes its own way and manages to capture the bulk of the microcomputer sales in major corporations, she says, this won't spell disaster for the industry.

"Only 25 percent of the desks in business are in the major companies," she says. "Before IBM, these were not the focus of the industry. With the PC, people moved opportunistically into direct corporate sales, because they had what the companies wanted. Now, the emphasis should swing back to the other 75 percent."