Zenith Has Kept Its Success a Secret

Richard O'Reilly designs microcomputer applications for The Times

Unlikely as it may seem that a company could become secretly successful in the microcomputer business, Zenith Data Systems seems to have accomplished it.

You seldom see Zenith computers advertised, and none of the major computer chain stores sell them. Yet Zenith’s market share has kept pace with that of other companies over the past several years, mainly on the strength of major sales to the federal government.

Zenith makes a computer that is compatible with the IBM PC yet doesn’t look like a clone, isn’t built like a clone and is even available in a kit from Zenith’s Heathkit subsidiary, if you’re not afraid of a soldering iron and want to save a few bucks. (Construction takes as little as 16 hours, and Heathkit stores have an excellent reputation for customer support.)

Part of the company’s lack of identity is rooted in the confusing variety of model names it has given its PC computer. The same machine is dubbed the Z-100 PC, Z-150 PC and ZF-151 because of circumstances too detailed and boring to explain here. Sold as a kit under the Heathkit label, it is the HF-151.


Whatever you call it, it’s an attractive computer, with a console 3 1/2 inches narrower than an IBM’s and a nicer keyboard on which important keys like Enter, Shift, Backspace, Insert, Delete, Control and Alternate have been made larger and placed more where your fingers expect to find them.

Different Internal Design

Inside, the Zenith uses the same Intel 8088 microprocessor as the IBM PC, but its internal design is completely different from that of the IBM and its many clones. However, it runs almost all the IBM software and accepts most of the expansion circuit boards that add functions to IBM and compatibles.

Because of the different internal design, however, Zenith is expected soon to announce a new expansion card that will make its computer imitate IBM’s new high-performance PC AT--and that’s something that IBM can’t do for its existing PCs even if it wanted to.

One reason the Zenith can be so easily modified is that it comes with a 168-watt power supply to feed those extra circuits, contrasted with the 63 watts for IBM.

At present Heath-Zenith Computer Centers are selling, at $2,279, a ZF-151 with two floppy disk drives, 320 kilobytes of random access memory (RAM), a parallel printer port and a serial modem port, a color/monochrome graphics display card, the MS-DOS operating system and Microsoft’s Word and Multiplan programs. The monitor is extra. Zenith can be reached at 800-842-9000.

One company that has not been the least bit obscure in the microcomputer world is Diablo Systems, a Xerox subsidiary that for years has set the standard for daisy wheel printers.

About a year ago, Diablo brought out the C-150 Color Ink Jet printer, priced at $1,295 and offering a resolution of 120 dots per inch vertically and horizontally. That is 11 times better that the screen resolution of a standard IBM color monitor in its four-color graphics mode. The Diablo prints in seven colors as well, by mixing the spray from its four basic inks--black, red, green and yellow.


When printed on a special smooth-surfaced paper, the colors are richly saturated, except for the black, which is a dull, dark gray. The machine will also print on acetate to create overhead transparencies.

The trouble with Diablo’s color ink jet printer was that software publishers had to write new printer drivers. (A driver is added to a basic program to instruct it how to operate a specific printer.) That has gotten the Diablo off to a slow start.

There are now more than 35 graphics programs, predominantly for IBM and Apple II series computers, that will drive the printer, including best sellers such as Lotus 1-2-3 and Symphony.

I found the color ink jet printer reliable and easy to use. There was no problem with clogged jets, even after it had sat unused for two weeks. The ink supply doesn’t go very far, however.


Each of the four ink cartridges can print 125,000 characters (text print speed is a leisurely 20 characters a second) or spray 5 million droplets in graphics mode. A letter-size page colored solidly requires a million ink drops on the Diablo, if you leave half-inch margins all around.

A Lot of White Space

Typical graphs and charts have a lot of white space, however, so you may be able to go a week or two between ink changes if you aren’t too prolific. A package of four new cartridges costs $9. (You replace each cartridge separately as that color runs out.)

Diablo has recently introduced its first low-cost daisy wheel printer, the Advantage D25, which prints at 25 characters a second and has a 132-column-wide carriage. It is substantially quieter than Diablo’s older, faster office printers.


With a list price of $745, the Advantage D25 uses standard Diablo daisy wheels and ribbon cartridges and offers four character widths, including an automatic proportional space mode that gives documents more of a typeset look.

It offers accessories such as a tractor feed for continuous forms and a single-sheet feeder for business stationery.

Another very impressive recent entrant on the printer market is the Okidata Okimate 20, a color thermal ribbon printer priced at $268 that runs almost silently and produces vivid colors.

Offers Bolder Colors


It offers even better graphics resolution and bolder colors than the Diablo Color Ink Jet, especially the black. Maximum resolution is 144 dots per inch horizontally and vertically.

To solve the software compatibility problem, Okidata, a division of Oki America Co., provides a program disk with the printer that allows it to print medium and high-resolution screen images created by a variety of commercial software packages. The printer uses a plug-in module to connect to the IBM PC and, later this year, to Apple computers.

It transfers color to special smooth-surfaced paper by heating a wax-ink ribbon--either black or three-color. The three-color yellow, magenta and cyan ribbon produces seven solid colors, including black, plus various shades and patterns of each.

The black ribbon costs $5.95 and will print about 60 double-spaced pages at either 40 characters a second in correspondence-quality print or 80 characters a second in draft-quality text. The color ribbon is $6.69 and is good for about 17 pages of text or 15 reproductions of a computer-screen graphic image.