CISC280 project 8

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Northampton County Area Community College *

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280

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Computer Science

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Dec 6, 2023

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CISC280 – Project 8 1. What is a race condition in software? Why are software race conditions difficult to debug? A race condition is when two or more concurrent tasks share a variable, and the order in which they read or write the value of the variable can affect the behavior of the program. Race conditions are extremely difficult to identify and fix because usually the two tasks do not interfere with each other and nothing goes wrong. Only in rare conditions will the tasks actually interfere with each other as they manipulate the variable, causing the error to occur. 2. Summarize the principal errors made by AECL throughout the life cycle of the Therac-25 linear accelerator. When accidents were reported, AECL focused on identifying and fixing particular software bugs instead of recognizing that the entire system was broken, not just the software. The system was not designed to be fail-safe. A system should be designed so that no single point of failure leads to a catastrophe, but by relying completely upon software for protection against overdoses, the Therac-25 designers ignored this fundamental engineering principle. Another flaw in the design was its lack of software or hardware devices to detect and report overdoses and shut down the accelerator immediately. Instead, the designers left it up to the patients to report when they had received overdoses. AECL also failed to communicate fully with its customers. It outright lied by saying that overdoses were impossible despite having been sued for that exact reason. 3. Debate the moral responsibility of three agents associated with the two Therac-25 overdoses occurring in Tyler, Texas: the radiation technician, the hospital director, and the programmer who wrote the code controlling the machine. You are on a jury in a wrongful death lawsuit. Your job, after listening to all sides of the argument, will be to award damages to the family. You must list a dollar amount and what percentage each party owes. The radiation tech should not have performed the first test knowing the communication system was malfunctioning. She also should have insisted that the machine worked properly, given the excessive error messages it issued every day. The hospital director should not have put the Therac-25 system back into use after the first malfunction, especially since it resulted in a fatality. The programmer failed to test the reused code to ensure it worked with the new system. Due to the removal of the hardware safety systems in the Therac-25, it was discovered that there were, in fact, bugs in the old code. Without the hardware interlocks in place to prevent harming patients, tragedy ensued. All this being said, I feel none should be held to as high a degree of responsibility as AECL itself. AECL used an extremely poor engineering method: only one programmer was assigned to creating the complex, real-time software; formal software specifications and testing criteria were not written; very little software and system testing were performed. Also, when old bugs are fixed in a program, a whole slew of new bugs tend to pop up. AECL’s claim of safety improvement after machine fixes were completely unfounded. AECL’s denial that the machine could malfunction, despite finding and fixing several problems, was groundless.

CISC280 – Project 8 In a lawsuit involving only the radiation technician, the hospital director, and the programmer, I would award a total of $3M, with the amount owed split evenly ($1M each) between the respective parties. 4. What is the difference between the verification of a computer simulation and the validation of a computer simulation? Verification is the process of determining if the computer program correctly implements the model. Validation is the process of determining if the model is an accurate representation of the real system. 5. The following reasons have been given for the failure of computerized systems: a. A system designed for one purpose was used for another purpose. b. Software was reused without adequate testing. c. There was an error in storing or converting a data value. d. A line of code became a single point of failure. e. The overall system was too complicated to analyze. f. There was a software race condition. g. Too much responsibility for safety was put on human operator(s). h. There was another software error (other than those listed in a–f). For each of the following systems, select the principal reason or reasons why it failed to operate as specified. 1. Patriot missile a, c 2. Ariane 5 b 3. AT&T long-distance network d 4. Mars Climate Orbiter c 5. Mars Polar Lander h 6. Denver International Airport baggage system g 7. Tokyo Stock Exchange f 8. Direct-recording electronic voting machines c 9. Therac-25 f 10. Tesla Version 7.0 (Autopilot) g 11. Uber self-driving test vehicle g 6. Google, Tesla, and several other car companies are working on self-driving cars that would allow computer-controlled automobiles to travel faster and closer together on freeways than today’s human-controlled cars. What kinds of safety devices would have to be in such a system in order for you to feel comfortable using an intelligent highway? There is no safety device in the world that would make me comfortable using an intelligent highway. There is WAY too high a risk of the system being hacked into or of system failure for me to ever want to use autonomous vehicles or an intelligent highway.

CISC280 – Project 8 7. Take the moral machine test at https://www.moralmachine.net/ . This site gives two scenarios for a self-driving vehicle. It is intended to gather information on moral decisions (crowd sourced self- driving data!) Go through a few scenarios and report on your decisions. What made you decide one scenario over another? Who is more important, passengers or pedestrians? Children, adults, or seniors? What is your process for determining the outcome of the scenarios? This was such a Sophie’s Choice activity!! The presence of animals made a HUGE difference in my decisions. As for passengers vs. pedestrians and children vs. seniors, my results showed that I slightly favored protecting passengers (I never chose to save the pedestrians when they were illegally crossing, which perhaps stems from my spending so much time in NYC as a kid) and, though this was not a choice I was conscious of making, I completely favored saving children over seniors (there most likely were pets involved in those scenarios). 8. Suppose someone uses an app to summon from a taxi service a ride in an autonomous automobile. The taxi arrives, the customer gets in, and the car begins traveling to the desired destination. The customer is the only person in the taxi. Along the way, the taxi runs a red light and collides with a human-driven automobile that had the right of way. Who should be liable for the accident: the company that manufactured the vehicle, the taxi service, the customer, or someone else? The manufacturer and the taxi service should be liable. It is their responsibility to ensure that the product works as intended and will not malfunction and cause fatalities. 9. Should an ecommerce site be required to honor the prices at which it offers and sells goods and services? (See https://gamerant.com/gamestop-free-games-glitch/ as an example) Yes, they should be. It is not the consumer’s fault if the website has a glitch. 10. While waiting for an appointment with your physician, you see a brochure advertising a new surgical procedure that implants a tiny microprocessor inside your skull just behind your left ear. The purpose of the chip is to help you associate names with faces. The procedure for inserting the chip is so simple that your physician is performing it in his office. Suppose your career takes you into sales, where such a device could help you earn higher commissions. What questions would you want to have answered before you agreed to have such a device inserted into your skull?

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CISC280 – Project 8 I would definitely want to know about the tracking abilities of the chip. I’d also want to know if everything I was viewing was being recorded and monitored by the manufacturer or another entity. In addition, I would want to know about any associated health risks caused by having such a microprocessor implanted so close to my brain. 11. Over a period of seven years, about 500 residents of Freeport, Texas, were overbilled for their water usage. Each resident paid on average about $170 too much, making the total amount of the overbillings about $100,000. The city council decided not to issue refunds, saying that about 300,000 bills would have had to be examined, some residents had left town, and the individual refunds were not that large. Did the city council make the right decision? Would you have recommended a different outcome? The council made the wrong decision. It is not up to the council to determine how much of a refund is “not that large.” $170 is almost 3 months’ worth of electric bills for me. The city overcharged the residents for their water usage; therefore, the city should be required to reimburse all the residents it overcharged. The cost of the city having to do so (in time, money, and resources) shouldn’t matter. That’s not the residents’ responsibility. 12. A start-up company called Medick has been developing an exciting new product for handheld computers that will revolutionize the way nurses keep track of their hospitalized patients. The device will save nurses a great deal of time doing routine paperwork, reduce their stress levels, and enable them to spend more time with their patients. Medick’s sales force has led hospital administrators to believe the product will be available next week as originally scheduled. Unfortunately, the package still contains quite a few bugs. All of the known bugs appear to be minor, but some of the planned tests have not yet been performed. Because of the fierce competition in the medical software industry, it is critical that this company be the first to market. It appears a well-established company will release a similar product in a few weeks. If its product appears first, Medick will probably go out of business. Discuss the best course of action for Medick based on five stakeholders representing the software engineers programming the device, the sales force that has been promoting the device, the managers of Medick, the venture capitalists who bankrolled Medick, and the nurses at a hospital purchasing the device. The best course of action would be for Medick to focus on fixing the bugs and performing the necessary tests. As a hospital administrator or a nurse, I would rather see a company be honest and determined to produce a product that works as intended than receive a subpar product that had the potential to wreak havoc and potentially catastrophic results for patients and, in turn, the hospital. As a manager of Medick, I would feel the same way. If the stakeholders and the venture capitalists had any sort of conscience, they would as well.

CISC280 project 8

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