United States Postal Service
Zip codes and postage rates
Zip codes and postage rates
While I worked for the USPS from mid-1973 to mid-1978, I conceived and wrote a postal clerk CAT (computer-assisted training) program on my home DEC PDP-8/e computer which I had purchased new from DEC in 1971 May (and which put me in the first dozen or so home computer owners in the world). After a demo of the system to Salt Lake City Postmaster Bob Greenberg, the USPS bought a system similar to mine and I implemented it on their machine. During my USPS employment, I re-wrote the system several times. I wrote a special interrupt-driven operating system for it which used 8K 12-bit words of memory. Another 8K I devoted to the re-entrant training program. Another 8K I used to hold the variables associated with each of 12 similtaneous users. The remaining 8K I used to run the DEC OS/8 operating system as a background job running under my special operating system. The entire project consisted of about 25,000 PAGE8 assembler statements. The system would drive 12 VDUs (Video Display Units) each at 2400 baud (that was as fast as most VDUs would reliably run in those days). I chose 12 VDUs as a max because I had conducted hard disk access tests that revealed that the DEC RK05 disk could handle only about 13.5 random disk accesses per second. Since each user needed one random disk access per second for their MP/LSM training at 60 letters per minute, I felt that 90% of the physical disk movement capacity was all that we could expect. When I explained my USPS project to my University of Utah computer science faculty advisor, Dr. Elliot Organick, he felt that the PDP-8/e had insufficient power to deliver the needed response. At the first full-scale test of the system in Southern California, I had just barely completed a 3-week total re-write of the OS and training code (yes, there were several 72-hour days). The first test concluded successfully; but a few seconds after the test, the OS crashed!
The training program not only trained postal clerks in manual distribution schemes, but also trained SP/LSM and MP/LSM operators. I even wrote a training segment for the USPS's brand new "flat" sorter which was (at that time) experimental in Salt Lake City and Philadelphia. In addition to the training aspects of the project, one could run DEC's OS/8 operating system in the high 8K of memory which allowed editing of the disk's mail distribution scheme files. When one completed the editing of a file, not only could it then immediately be used as an interactive training tool on any of the 12 VDUs, but the complete distribution scheme could be printed as a training booklet on the printer.
This project was probably the high point of my computer science career (although I have written far larger and more complex projects since). The USPS awarded me the second largest incentive award for 1978 ($1,200) because I had saved the service more than $120,000 in just the Salt Lake City Post Office alone. All told, I personally installed the system in 7 major post offices around the country. The greatest rewards I received from this project, however, were the thanks from my fellow postal workers in the Salt Lake City post office. You see, the Postal Service takes "scheme" exams VERY seriously. The minimum passing score on an MP/LSM scheme exam is 98%. If you fail an exam, they don't wish you better luck next time; they wish you good luck in finding a new job! I had the experience of having elderly postal clerks come to me in tears and thank me for saving their jobs! They told me that a few hours on my computer-assisted trainer and they could enter the scheme exam room with a level of confidence thay had never previously experienced.
Although I wrote every line of code and did the systems analysis, others contributed to the project. Bob Greenberg had the "guts" to fund the project and the Salt Lake City PEDC (Postal Employee Development Center) managers, Dale Wilcox and then Dorothy Moreton, wholeheartedly backed the project. Newell Wilson, assistant PEDC Manager, had a degree in psychology and contributed much to my understanding of human nature and our lengthy discussions translated to a better human-to-machine interface for the training system. Bonnie Sutphin traveled with me to the six other major post offices where the system was installed and worked tirelessly to train their staffs.