Perry_Cox_volunteer

Perry Cox, volunteer Watch Perry construct his story. Her.e's the first draft attempt..

Jan 16, 2014 I am writing my story in response to and in consideration of the concepts delineated on the HCLE Internet web site for computers and education; designated as the Computing in Learning and Education Project – [|www.hcle.org]. I am being guided as to the contents of my story by two sentences in the early part of the [|www.hcle.org] home page. “The first thing to do is to write your own story about how you learned to use computers.” “We are particularly interested in what got you interested, what resources you used to get started, who helped you, who taught you, how you taught yourself, what organizations, groups, schools, classes added to your learning and what kept you from going further.” I started being interested in electricity and electronics in high school; after studying electronics in the Air Force; after high school. I studied electronics further in college. At some point I made the decision to go in the direction of digital electronics. I was attracted to the fact of the determinism of the signal levels being either high or low – for a 1 or a 0. My first job out of college was for a company using discrete transistors and resistors – and capacitors and diodes – to make flip/flops and logic gates. I made binary counters, and binary coded decimal counters. The technology and industry then moved to small scale integrated circuits were each integrated circuits implemented multiple flip/flops and logic gats on the silicon of the integrated circuit. The integrated circuits had pins coming out of the two long sides of the rectangular shaped plastic package. They were intended to nominally go through holes in a printed circuit board with copper traces that interconnected the pins from one integrated circuit to another. The first small scale logic circuits I worked with used a transistor to pull the output low, and a resistor to pull the output high. When the transistor was on, the output was near ground. When the transistor was off, the output was near Vcc – which was 5-volts. Inherent in this implementation was that the signal transition from near 5-volts to near ground when the transistor was turned on was much faster than the signal transition from near ground to near 5-volts when the transistor was turned off. This was called Resistor Transistor Logic (RTL). This was replaced by Transistor Transistor Logic (TTL), where the pull-up resistor was replaced by a transistor circuit. This enabled the signal transition times from near plus 5-volts to near ground, and from near ground to plus 5-volts to be similar. I did a lot of circuit design, and wire-wrapping prototypes using both RTL and TTL small scale integrated circuits. Wire-wrapping was a convenient way of interconnecting the pins along the long sides of the plastic packages of the integrated circuits; without using the copper traces on a printed circuit board. This was all a beginning for me; to use small scale integrated circuits to implement logic designs that would perform logic functions. This was all a form of digital electronics where the various input and output signals were either a logic 0 or a logic 1. The logic 0 was usually a near ground level. And the logic 1 was usually a near 5-volt level. This was the case with the commercially available small scale integrated circuits; as opposed to the early implementation of digital electronics and digital computers with vacuum tube technology; and before that using relays. Intel was using digital logic in the form of custom integrated circuits for their customer to implement calculators. It was doable, but compared to software, it was cumbersome and difficult to change the functionality. People at Intel had the idea of implementing the functionality that was provided by the custom integrated circuits by using a different methodology to achieve the same functionality. This different methodology was to use electronic circuits to sequentially execute instructions that were contained in a program. So if the variety of instructions was great enough to put together a group that would be executed sequentially. Then the functionality equivalent to what was accomplished via custom designed logic circuits could be accomplished. From this paradigm shift came forth the microprocessor. Not so much as we know it today, but in a more primitive form. It all began life as a concept for replacing custom designed logic chips for a calculator. Then evolution took place and things changed in the form of the implementation of the microprocessor became more and more general purpose. The “word” size became 8-bits, and the variety of instructions grew to be able to perform sequential execution that accomplished more and more complex tasks. In all of this I became more and more excited and enthusiastic. I was so fascinated by the possibility that whatever I could conjecture, I could make happen by combining a series of instructions. It was this excitement that pulled me forward from one level of understanding to the next. End of this part of my story - Perry