Columnist: July 18, 1996

After 10 pm, my house falls silent, the kids long since tucked away and my wife reading or in dreamland. This is my time, when I get a chance to spend what little energy remains at the close of day on avocations. One of these hobbies is amateur astronomy, for which I spend a fair number of these all-too-limited hours poring over astronomy charts and planning the next observing session.

For my hobby, I went to buy a pair of dividers the other day at an office-supply store. No other tool is as useful for extracting the stars' celestial positions from the charts. Yet, somehow, these dividers (along with scissors and tape) disappear into the land of the unknown with astonishing rapidity; the youngsters always answer my queries with "I don't know." This time, the store's shelves were bare. The poor substitute was a cheap compass, which immediately puzzled my son. He assumed that it was yet another new marvel of technology like those that fill his environment but wondered where the battery went.

We talked about the fine art of drawing circles, but my mind wandered back to the life of a young engineer, seemingly several thousand years and five generations of µPs ago. Long ago, back in the '70s, no PCs or similar tools we now take for granted existed. The life of a digital designer was very different indeed. Computer folks used the same tools as civil engineers. Drawing boards—6×3-ft flat panels propped at "comfortable" angles—dominated offices. Engineers lived in high chairs hunched over the drawing board with mechanical pencil in hand, creating wonderful silicon inventions using the same paper and lead that writers and philosophers have relied on for centuries.

Drafting was a skill all mechanical engineers mastered in college, but, for some reason, the University of Maryland, which I attended, considered drafting unimportant for electronics guys (all guys—there were virtually no women in the field then). Some engineers were nothing short of gifted artists, creating schematics that filled the paper in a visually pleasing way. Others, including me, could hardly draw a straight line, even with the aid of a drafting machine. Lettering was a fine art. It's hard to imagine this situation now, when we select from a thousand fonts with a few mouse clicks, but neat signal names were essential. Some designers used lettering templates. I always found these too cumbersome and, so, subjected all readers of my drawings to the same illegible scrawl that the nuns had punished me for in grade school.

Every branch of engineering had its unique set of templates. Digital designers used a handful of plastic stencils that contained the entire stock of resources we worked with: AND and OR gates; inverters and "not" circles; and various-sized squares and rectangles for µPs, memories, and everything else. Large chips were rare then; the largest might have a whopping 64 pins, which wasn't too hard to draw. We drew resistors, capacitors, and other components using similar stencils. With a little practice, you could whip the pencil through the zigzag of a resistor template in no time, though a not perfectly sharp pencil always resulted in only a hazy image of the part.

Though Luddites scoff that computers let us make mistakes at new, unprecedented rates, even with these crude tools, we were quite competently creating errors faster than we were creating decent designs. We used erasers—in every form imaginable—in lieu of a "delete" key. Most of us made so many mistakes that we used electric erasers, a motorized drill-like device that spun a cylinder of gumlike material. Though these quite effectively removed vast areas of pencil lead, careless use always produced a hole in the vellum—gauzy semi-transparent material that was pretty tough. Then what? I suppose some folks started over, recopying the entire drawing onto fresh paper. Where I worked, we glanced furtively over our shoulders and rerouted signals around the hole.

Hand-drawn designs by sloppy electronic folks had much wider lines and larger lettering than those we make on computer screens today. As a result, the drawings were big. Although some folks used C-sized, 17×22-in. paper, the norm was D-sized, 22×34 in. Engineers, production people, and technicians all looked like quintessential architects, with stacks of these monsters on every flat surface. When troubleshooting a new design, the first step was to position a big table next to the lab bench—just to hold the drawings.

Today, we primarily use A- and B-sized paper, because that's all that laser printers handle. You can fax or photocopy these drawings without trouble. An ordinary filing cabinet is the perfect storage place. Back then, every business had a "drawing room," dedicated to storing (in cabinets called "flat files") and reproducing these huge representations of our tiny circuits. Larger companies had people whose entire role was to copy and file these drawings. No copier then or now could handle a sheet of D-sized paper.

One reason we used vellum was its transparency. An engineer duplicating a drawing first put it atop an equal-sized paper coated with a light-sensitive chemical and ran it through the Ozlid machine. This beast beamed an intense light through the vellum, exposing areas without pencil marks. It then treated the paper with ammonia, which turned the unexposed areas blue. The ever-present smell of ammonia (and second-hand cigarette smoke) was simply a part of the engineering environment. Once, the ammonia line broke in the middle of the night. In the morning, the entire building was uninhabitable. Fire-department fans eventually sucked the fumes out, but we found strange chemical changes in our environment. One secretary's fake flowers changed to a wonderful purple shade. Many pictures hanging on walls now looked like 19th century daguerreotypes. And, several thousand dollars' worth of unused Ozlid paper became completely developed, bright-blue reminders of the incident.

Now, drawings have no value. Did you spill coffee on a schematic? Just print a new copy. The information itself is immensely valuable, but its paper incarnation is sacrificial. Before CAD systems, the paper was the only representation of a drawing. The labor required to re-create one was so immense that to lose or mar a schematic was simply inconceivable.

It's funny to realize that one promise of computerization was the paperless office; yet, paper is now so prevalent that it's worthless. By contrast, in the olden days, an original drawing was a holy relic. Copies were scarce because of the cost of duplication and the nuisance of storing the bulky papers. The regulations said that no drawing left the files unless it was being duplicated or was on an engineer's drafting board. Most of us flouted these rules when the Ozlid machine, which required an hour to warm up, was off at night and we were engaged in a furious troubleshooting war. Living dangerously, with the original by the bench, we'd hope to be done by morning when the drawing Gestapo came in. More than one drawing went back into the files with food stains in the corners.

I suppose it goes without saying that pc-board software packages were nonexistent. Either our engineers or outside contractors, leaning over a light table, routed tracks by placing black tape on Mylar. It was a game of chess: The best board designers developed a mental plan of attack that, they hoped, would let them get all of the tracks down without running into dead ends.

How things have changed! Now, it's great fun to watch the routing program automatically plopping traces onto the virtual board at a speed that takes my breath away. In the '70s, a big board took weeks, even months, to design.

Designers routed on Mylar, because no paper is dimensionally stable when subjected to humidity variations, and they made the pc board via a photographic reduction of the drawing. My dad, a mechanical engineer from way back, tells me that, in the '50s, they had the same problem with paper when designing forms for constructing airplanes. Because Mylar didn't exist then, designers drew on starched linen in ink. Apparently, the linen was stable, but it couldn't tolerate water. One drop of sweat dissolved the starch, ruining the drawing. And, this situation was before air conditioning was common.

It's fascinating to see things that have not changed with time. Data books are the best example. I've been convinced for years that CD-ROMs, floppy disks, or the Internet would reduce the engineering library to a single shelf. Yet, we still tramp to the local shows, filling our trunks with 100 lbs of paper, just as we did in the '70s. There are some rays of light, though. Just the other day, I logged into AMD's Web site and downloaded an Acrobat rendition of a data sheet. Now, that was cool—conveniently getting up-to-date information without dealing with a uninformed salesperson.

We learn many skills in life. Some never atrophy. My fingers recalled the compass from two decades past and guided my son's hand around in circles—small ones and big ones. With a bit of practice, he was ready to solo. Despite the wonders of computer technology, there's still value in fine-motor skills. Kids do art projects not only to express themselves but also to gain mastery of their own fingers. As for me, I'm thankful for modern CAD. I'd never go back to those tedious days of yore.