Reading 5

The Therac-25 devices were built with lasers that could kill cancerous tissue deep inside the body. Because of the power intensity it would be likely that it would cause damage to healthy tissue as well. So chemotherapy is used to heal the patient and allow the body to heal properly. Unfortunately, there were 6 patients that were exposed to overdose of radiation leaving 4 deceased. According to the investigation the software that ran the hardware had bugs and the machine’s safety relied on the computer. In other words, the hardware had no type of detecting sensors that could determine if the software was bugged or not. Therac-25 accidents are known to be the worst software bugs in history. I believe that we should be discover the abilities of the devices we use a lot more so that we can prevent horrible things such as these to happen to people who are already suffering as it is.

 

Regarding the therac-6 and 20 (which came before the therac-25 hardware), interlocks prevented the operator from doing something dangerous. Once the technician entered a prescription the computer would do the rest of the work. When therac-25 was designed, manual controls and hardware were removed, and the interlocks made it so that the computer could keep track of the detection of errors.

 

We can see that we are quickly moving into a society where computers are embedded into most of the things around us. Because of this, people can be both physically damaged and have their personal information compromised. Many systems that we don’t take to be system-critical systems are, in fact, system-critical, and they are beginning to work together. It is also important to realize and take into account some limitations of software engineering because it may involve many different technical fields. A safety-critical system is responsible for the effect on one or more people, so for it to fail is imaginable.

 

Some challenges facing software developers include, for example, the need for increased testing of programmer code. There could be hidden bugs that programmers and testers are unaware of—in order to prevent this, we need to implement strong testing procedures and encourage programmers to be more aware and careful when working in a safety-critical system. Another challenge facing software developers working safety-critical systems besides safety which is extremely important is security. I believe the security of things as well as the safety needs to be looked into much more carefully because it seems to be something many people overlook now-a-days. For example, one way to look at it is people’s security in these high risk of attack buildings that lie in major cities all over the world. Every architecture must keep in mind the ability of outside attacks on the buildings they are designing. Peoples security in those buildings is extremely important! Either way we look at a situation like this the main point lies in the fact that the developers designing and building any kind of product no matter the shape or form must keep in mind many factors that can affect the users.