Timeline Analog 2. John Buck
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Название: Timeline Analog 2
Автор: John Buck
Издательство: Ingram
Жанр: Изобразительное искусство, фотография
Серия: Timeline Analog
isbn: 9781925108583
isbn:
Peters graduated with both degrees and started as a software engineer at Digital Equipment Corporation (DEC) in the Small Systems Engineering Group. DEC, or Digital as it was often called, was a major American company in the computer industry from the 1950s to the 1990s. It eventually became second only to IBM.
It was an intensely creative and challenging and open working environment, I guess somewhat like Google is today, DEC was back then. My relatives asked me where I worked and I would say, ‘Digital’ and they would say, ‘Oh you make watches!’ It was the only thing they knew that was digital, a digital watch.
While it became famous for the VAX line of computers, Digital's financial success was built on the PDP (Programmed Data Processors) minicomputers. It created the PDP-1 in 1959 and then iterated faster more capable versions through the next decade.
I worked on a number of real time operating systems projects and was part of the four-man team that created RT-11, the real time (RT) operating system for DEC’s PDP-11 microcomputers. I gained a very good background in real time programming which turned out to be very important for editing!
Which is certainly real time to the extreme because there aren't many applications that are that hard as playing real time media.
Eric Peters was a key contributor to Avid in future but with the release of the PDP-11/20 in January 1970, he had helped create the platform for the world's first nonlinear computer editing system.
The joint venture between Memorex and CBS Television, CMX Systems, transitioned from analog to digital. Group manager Ken Taylor hired more staff to design the control systems, digital circuitry, disk pack switching and user interface for the unnamed editing system. Jerry Youngstrom recalls:
Obviously we needed some sort of program to ‘run’ the system. Memorex had put in an IBM 360 computer to aid the hardware group but the only person in the media group that knew how to program it was a statistician. For that matter in the wider engineering community there was almost nobody writing code. Programming was a brand new discipline. We were exceptionally lucky to find Dave.
David (Dave) W. Bargen worked at the Medical Diagnostics Operation of Xerox Corporation on N. Halstead Street, Pasadena, California. He recalls:
A friend heard about the new joint venture between CBS and Memorex and told me before he left Xerox to work for Memorex.
Bargen started at CMX in May 1970 and among his first were to choose a computing platform.
I selected the DEC PDP-11 computer.
The PDP-11 computer, released just a few months earlier, had 16,000 words of core memory (16 bit), no hard drive and ran at 3 to 5 microseconds per instruction. (about 1000 times slower than a typical PC today).
The PDP-11 was a new computer model. It was 16 bit but also handled 8-bit bytes efficiently, which would be helpful for hardware control. It had good performance for the money. The original CBS system had used a DEC PDP-8, but that it was at the end of its model life-span.
Bargen went to Bill Butler and Ken Taylor with his recommendation. He recalls:
At the time it was the preferred mini-computer. DEC was the original mini and a huge success until the advent of the Apple and PC. The PDP -11 had adequate power and speed, and supported all the peripherals we needed, including a punch paper tape reader/writer and the graphic interface which was quite new at that time.
Bargen's next decision, software coding.
Assembly (language) was used because of the need for speed and the limited memory capacity of the day.
He now needed software coders, who were uncommon in the Bay Area.
James (Jim) C. Adams Jr. had moved from Fairchild Semiconductor to Link General Precision. Link had created flight simulators for the Apollo Lunar Lander (above) and then the F-111 fighter aircraft.
I was using an Xerox Data Systems (XDS) Sigma 5, developing the radar simulator software for the F-111. With this, and all of my previous jobs, I was sent to the factory schools to learn the software development process as well as the underlying hardware philosophy of the specific computer.
DEC for the PDP-8, Scientific Data Systems for the SDS 930, Xerox for the SIGMA 5, as well as others such as Control Data Corporation (CDC)for their systems and Texas Instruments for analog/digital circuit design. At XDS the key take-away for me was how to process interrupts. An interrupt is a signal sent by a device that it needs attention. This is very different from a processor interrogating a device periodically to see if it either has data or is able to receive data.
Adams soon left Link.
I answered an ad in the San Jose Mercury-News for a programmer 'to work on a new innovative system'.
Adams became the first outside hire by CMX. He adds:
Once onboard I met my immediate manager, Dave Bargen, I was introduced to the concept of video tape editing. Specifically, the process of many camera takes, selected parts of each take which were to be linked together to create a deliverable package.
The older technology was to cut the desired part out of the original take and glue it to another piece cut from another piece. The newer scheme involved using a frame counting code recorded on the tape and recording a number of frames from that point to another tape.This required two machines able to synchronize to the correct frame code for each machine.
This concept had been carried to a computer to perform this task, rather than a dedicated hardware device that was quite operator intensive.
Adrian Ettlinger’s proof-of-concept system, employing a PDP-8, could perform a single recording, but only the one segment buried in the computer program. CBS wanted to create a two-part system, the first of which was to determine the segments and sequence of the original takes at low resolution, what we now call Offline editing, and the second part was to copy the edit decisions onto a blank tape at high resolution for review and eventual delivery to the broadcast stations. What became known as Online editing.
Bargen adds:
The first product priority was development of the low resolution offline editing system that became know as the CMX 600, because that was the most innovative, and had the most unknowns.
Adams continues:
From a control viewpoint, the offline process was pretty straight forward. Each frame of the original material had a frame code associated with it; this code tallied hours, minutes, seconds and frames associated with the time at which it was originally recorded. This frame count information was penciled into the program script such that any segment of tape could be quickly located from the script notes.
The frame count codes came in two variants: straight 30 frames per second СКАЧАТЬ