Levy_S-Hackers-Heroes-Computer-Revolution

Homebrew reviewers would examine carefully, and they would not only notewhether it worked or not but judge the relative beauty and stability of itsarchitecture. The layout of circuits on the board was a window into the designer'spersonality, and even superficial details like the quality of the holes by which onemounted the board would betray the designer's motives, philosophy, andcommitment to elegance. Digital designs, like computer programs, "are the bestpictures of minds you can get," Lee Felsenstein once said. "There are things I cantell about people from hardware designs I see. You can look at something and say,'Jesus Christ, this guy designs like an earthworm goes from one place through tothe end and doesn't even know what it was he did in the middle.'"Bob Marsh wanted Processor Technology to be known for quality products, and hespent the next few months in a frazzled state, trying not only to finish his projects,but to do them right. It was important for the company and for his pride as well.The process was not a terribly simple one. After figuring out what your boardwould do, you would spend long nights designing the layout. Looking in themanual that described the workings of the 8080 chip, you would jot down thenumbers for the various sections you wanted designating this section for an input,that one for memory and the labyrinthine grid inside that piece of black plasticwould begin to reshape inside your head. The effectiveness of your choice ofwhich sections to access would depend on how well and how accurately you keptthat vision up there. You would make a pencil drawing of those connections, withthe stuff destined to go on one side of the board written in blue, stuff for the otherside in red. Then you would get sheets of Mylar, lay them on a grid on a lighttable, and begin laying out the outline of the connections, using crepe paper tape.You might find out that your scheme had some problems too much traffic in onepart, the interconnections too tight and have to realign some things. One mistakecould blow everything. So you'd be sure to do an overlay of the schematic: placingthat on top of your taped-up design, you could see if you made some grievouserror, like hooking three things together. If the schematic itself was in error, forgetit.You would design it so that the board would have several layers; a different set ofconnections on the top and the bottom. You would flip the layout back and forth asyou worked, and sometimes the tape would peel off, or you would have littlepieces of tape left over, or a hair would get stuck somewhere: any of theseuncalled-for phenomena would be faithfully duplicated in the sepia reproductionsmade for you at a blueline house (if you didn't have money for that, you'd do acareful Xerox), and result in a disastrous short circuit. Then you'd mark up thelayout for the board company, telling where to drill and what needed gold-plating,and so on.