When I started this blog, I intended to write about more than displays and include some of my personal IC history. Today’s story is about Derek Roskell of Texas Instrument’s who led the UK-based design teams I worked with between 1979 and 1997 on a number of the most complex I.C.s done up to that point including the 9995 16-bit CPU, 34010 and 34020 Graphics CPU’s, and the extremely complex 320C80 and 320C82 image processors with a 32-bit RISC CPU and 4 (C80) and 2 (C82) advanced DSP processors on one chip. Every one of these designs quickly went from first silicon to product.
Having one successful design after the other may not seem so special in today’s era of logic synthesis and all the other computer tools, but back in 1979 we drew logic on paper and transistors on sheets of frosted Mylar plastic with color pencils that then were then digitized by hand. We then printed out large “composites” plots on giant flat-bed pen plotters (with each layer of the I.C. in a different color) and then verified all the circuitry by hand and eye (thank goodness by the mid 1980’s we got computer schematic verification).
In those days it all could go very wrong and it did for a 16-bit CPU call the 9940 and a spinoff version the 9985 that were design in Houston Texas in 1977-1978. It went so bad that the both the 9940 and 9985 were never fully functional, causing the designer to be discredited (whether at fault or not) and many people to leave.
In the wake of the 9940/9985 disaster, in 1979 management pick me, the young hotshot only 1.5 years out of college, to lead the architecture and logic design of a new CPU, the TMS9995, to replace the failed TMS9985. There was one hitch, they wanted to use a TI design group in Bedford England. So after some preliminary work, I packed up for a 6 month assignment in Bedford where I first met Derek Roskell.
To say Derek is a self-deprecating is a gross understatement. The U.S. managers at TI at the time were more the self-assertive, aggressive, “shoot from the hip,” cut corners (which resulted in the 9940/9985 debacle) and generally didn’t take well to Derek’s “English working class” (said with great affection) style with the all too frequent laugh at the “wrong” time.
When I first met Derek he was this “funny old guy” who at had worked on “ancient” TTL technology. He was around 40 and seem like an old man in a world of engineers in their 20’s and early 30’s who he led. As it turned out, Derek was the steady hand that guided a number of brilliant people who worked under him. He made sure my “brilliant” architecture and logic design actually worked. You don’t have one successful design after another, particularly back then, by accident.
Upper management was always pressuring to get thing done faster which could only be accomplished by cutting corners. They called Bedford a “country club” for resisting the pressure. Derek was willing to take the heat and do things the “right way” because he understood the consequences of cutting corners.
For most engineers fun part of engineering is doing the original design work. That is the “creative stuff” and the stuff that gets you noticed. Also most engineers have big egos and think, “of course what I designed works.” But when you are designing these massive I.C.’s with hundreds of thousand and later millions of transistors, even if 99.99% of the design is correct, there will be a hopeless number errors to debug and correct. Most of what it takes to make sure a design works is the tedious process of “verification.”
A couple of months back I had a small reunion in Bedford with some friends from the old days including Derek. Everyone remembered Derek for one thing he constantly chided the designers with, “If you haven’t tested it, it doesn’t work.” Pretty good advice.
TI, like most companies today, in their search for “shareholder value” closed the large Bedford UK site around 1995 but still kept Bedford MOS designers who had so many proven successes and moved them to a rental building Northhampton. Through the years TI kept “consolidating/downsizing” and finally 2011 it shut down the last vestiges of their design operation in England and losing a number of extremely talented (and by then) senior people.
Below is a picture taken of the design team in Bedford that worked with me on the 320C80.