The Tandon Corp. has become the newest and most enthusiastic proponent of a new trend in personal computers, broadly known as modular upgradeability.
That simply means that one can take the microprocessor and related components out of an older computer and replace them with a faster or more powerful set of chips, in effect getting the latest technology for less money than it would cost to buy a complete new system of comparable power.
For computer users who are interested in moving to new generations of software, including the performance-hungry Windows and OS/2 operating systems, upgrades are a very attractive alternative to buying a new machine.
Several other computer makers, including AST Research Inc. and the International Business Machines Corp., already offer PC models that can be upgraded at the microprocessor level by replacing the main internal circuit board.
The new Tandon SL-III models, which were on display last week at the PC Expo computer trade show in New York, are unusual in that the components can be replaced without opening the computer case.
The process, Tandon officials said, is similar to inserting a videocassette into a videocassette recorder. It takes about a minute and requires no tools. Hard disk drives, too, can be plugged in without opening the box.
In contrast, the board-level upgrades offered by other computer companies typically require the user to open the case and perform minor surgery, but even so the process can be completed in less than 10 minutes.
Modular upgrades "simplify the task of coping with very short life cycles of microprocessors," said Bruce Stephen, director of hardware research for the International Data Corp. of Framingham, Mass. "We're in a time when processor technology turns over every nine months or so, so it makes sense to buy a safeguard against obsolescence."
"I don't see any reason not to buy one" of the upgradeable systems, said Jim Seymour, a Texas-based computer consultant who advises many large corporations. He said upgradeable systems were a trend, not a gimmick.
Mr. Seymour noted that most computer companies do not charge a premium for upgradeable systems or replacement boards, so there ought not to be a financial penalty for the user.
In addition, the upgradeable computers have many advantages, he said. They simplify design, manufacturing and inventory problems for the computer company.
They allow dealers to keep fewer parts in stock. They reduce the need to train workers when new technologies emerge, and they make it easier to repair and maintain the systems.
Also, because an upgrade cartridge or board can be designed, tested and certified much more quickly than a complete PC system can, new chips can be put into the hands of customers much faster.
Mr. Seymour cited the ability of IBM, through a board-level upgrade to the 386-based PS/2 Model 70, to offer its customers the first Intel Corp. i486-based chips on the market last year.
In fact, IBM is so proficient at speeding upgrades to market that last month it announced an Intel i486 50-megahertz upgrade for its PS/2 Models 90 and 95, even though Intel itself did not officially announce the existence of the chip until last Monday.
Only the most power-hungry users really need instant access to the newest technologies. Most upgrade customers, including the ones Tandon is seeking, are likely to be interested mainly in saving money and preventing headaches.
Tandon, of Moorpark, Calif., is best known in this country as a maker of floppy disk drives; it supplied the ones in the original IBM PC 10 years ago. It began offering full computer systems last year.
"Tandon's SL-III eliminates the need to buy another computer ever again," said Graham Beachum, the head of Tandon's North American operations, in a statement that upgraded the level of hyperbole in the industry.
The new SL-III "standard unit" systems offered by Tandon have two megabytes of working memory, expandable to 32 megabytes; a single diskette drive; seven expansion slots and room for four extra disk drives; a keyboard, mouse and monochrome monitor, and Microsoft DOS and Windows.
The standard unit has a list price of $895, but that does not include the processor or hard disk, a situation similar to buying a car without an engine or a gas tank. The user can then choose a processor cartridge and storage system based on the level of power needed.
A 286 processor operating at 16 megahertz costs $795. A 20-megahertz 386SX processor costs $1,165 or $1,395 depending on whether it has a high-speed data cache system.
An i486SX chip running at 20 megahertz is $1,795, and a full-powered i486 at 33 megahertz is $2,495.
Tandon offers five different hard disk modules, including an 80-megabyte disk for $345, a 110-megabyte module for $535 and a 200-megabyte module for $725. A "super VGA" color monitor is $325.
Piecing it all together, one could buy a i486SX-based system with 110 megabytes of storage and a super VGA color monitor for a list price of $3,550.
According to Tandon's plan, a couple of years from now you could pop out the old cartridge, pop in a new one containing Intel's 100-megahertz version of the i586 chip (or something like that), and be on your way.