When engineers Cal Jureit, Walter Moehlenpah, and Bill McAlpine witnessed the impressive launch of the IBM System/360 in July 1964, they surely suspected that computers could bring relief from the increasing burden of special engineering requests. Even though none could afford the System/360, they sought lesser-priced systems that could expedite their work. Jureit and Moehlenpah both signed leases on the engineering-oriented, desk-sized IBM 1130 that used Fortran and came with MIT’s Structural Engineering System Solver (STRESS) analysis program.
The impact of installing the first-ever computer in design offices that were doing everything by hand is hard to imagine today. At the time, these offices were stressed by a continually escalating level of tedious work. By 1970, Gang-Nail had about thirty people engaged in truss design and Hydro-Air had about twenty, but few if any of their associates had laid eyes on a computer. The majority were draftsmen, who worried that this new contraption would take their jobs. Even the engineers had trepidation, since none had taken a computer course, and they knew they would have to do the work, since local colleges had just started awarding computer science degrees and graduates with engineering backgrounds were in short supply. That’s why someone such as myself with only two years of engineering and computer classes could be hired by Hydro-Air.
Fortunately, truss engineers quickly realized that learning computer technology was only one part of the continuing education required to maintain their professional standing. More importantly, though, they realized that well-programmed computers had the potential to spare them from the daily drudgery of their jobs. Among these engineers was Ted Dasher, who had moved from the famed Bell Labs to south Florida where he was fortunate to work with Bob Brooker at Sanford Truss. Together, they created the first fully featured truss program that would go on to power the first stand-alone in-house truss computer, Lenny Sylk’s Forest Products system.
Engineers did find early structural analysis programs, such as STRESS, that could analyze attic frames and other non-triangulated structures they had previously disdained. However, these programs did not design plated joints, and did not take advantage of the uniqueness of wood truss geometry, rendering them overly conservative. As a result, truss engineers were compelled to write their own programs to remain competitive. By the time I arrived at Hydro-Air in 1970, our engineers had already produced a capable program that was stored on a deck of about 900 computer cards. The program loaded in about seven minutes, after which batches of individual truss designs took several minutes each. By early 1972, our IBM 1130 computer was able to process all incoming jobs and still leave plenty of time for running program improvements. During this time, engineers were able to shift their focus from doing hand calculations to checking computer output, thereby verifying the accuracy of the programming. Draftsmen were doing more cutting and pasting than drawing and lettering. The end result was a program that could be shared with fabricators, with the requisite engineering cautions.
Even before plate suppliers had computers, Camilla Hurwitz was hard at work writing code, using time-sharing to acquire the necessary computer time. This mid-1960s innovation gave small users near parity with much larger ones, and Camilla gained a jump on the entire truss industry from her office at Woodtech, a small fabricator in suburban St. Louis, MO. While the big guns were equivocating on hardware, Camilla was writing the first-ever cutting program on a Western Union teletype so she could avoid doing cutting lists by hand. While Woodtech had obtained Gary Sweatt’s Clary manual when they bought their component saw, Camilla had learned that there was a better way during her pursuit of a PhD in chemistry. When the Clary Corporation realized the potential of her work, they negotiated a buyout with Camilla and her husband Dan, a professional structural engineer, and moved them to the Dallas, Texas area. After a short stint there, Dan and Camilla left Clary amicably, and, in 1970, incorporated On-Line Data in Richardson, TX, becoming the first to offer cutting lists via time-sharing.
On-Line Data’s program quickly gained customers throughout the truss industry, and compelled the plate and engineering suppliers to follow suit. Gang-Nail was the first to respond, seemingly outflanking On-Line by offering both engineering design and cutting programs. However, even some Gang-Nail plate customers, like Trussway, retained On-Line Data’s program, since they had already mastered it, and also because On-Line Data’s program could cut nearly any planar structure through a capability that later became Sketchpad. Subsequently, when Hydro-Air offered a similar methodology, they were initially barred from providing it due to infringement of On-Line Data’s copyrighted input form. While Hydro-Air overcame that limitation, this early skirmish was but the first of many in the coming software competition.
All of these time-sharing applications were line-input based, with designated fields for each data item. Users filled out a form and then typed the data from these fields, separated by commas, onto a teletype machine. Jobs could be stacked vertically, as they were delineated by a # on the first line. Initially, users punched a paper tape offline, set a telephone handset into an acoustic coupler that converted digital signals into audio tones, initiated a connection to the time-sharing computer, and then fed the paper tape back into the teletype. Then, jobs were stacked in the mainframe’s input queue and processed as a batch when time was available.
Users had no direct interaction with the remote computer, and they faced a delay of several hours in receiving the results. But, regardless of how awkward this sounds today, having access to a computer gave designers the opportunity to obtain much better results, a far cry from calling in or faxing design requirements. By the end of the 1970s, however, designers finally got to work on a dedicated computer workstation.