Okay, so welcome back to Introduction to Software Engineering.

I have today two housekeeping remarks that I would like to stress.

One thing is that apparently in the last exam period there have been numerous attempts of

fraud within examinations and from now on we have to centrally report any fraud attempt because

apparently there have been students that have tried to cheat in multiple exams in the same exam

period and we now have to report it to a central place in the School of Engineering.

And if you are cheating in multiple exams then it could be that you will be removed from the

university. So this is a serious thing and this is now centrally being handled. So that's a new

change that is being adopted across the School of Engineering probably starting this semester and

I don't know whether this will also be rolled out university-wise. So it's the first housekeeping

remark that I have to make. So be careful, please don't cheat in the exams, prepare yourself properly

and then pass the exam. The other remark that I have to make is unfortunately I'm traveling again.

So next week and the week after I will have to broadcast the lecture again and of course I will

also upload the recorded versions that I directly recorded on my machine also to the video portal

such in case you need very good audio quality. I'm not sure how the recording turned out here

from the broadcast in the lecture hall but I will make that one also available so actually

directly after this lecture just in case that you know in the next two weeks I have unfortunately

have to broadcast but of course I'm there for questions and it will be live but I have to

accommodate travel. All right this brings us now to our lecture Software Engineering and so far just

a recap we talked about how to run essentially a software project. This is the general idea about

this lecture how to engineer software. We talked in the beginning general about different approaches

from more static to more dynamic ones in particular agile programming was a big thing. We also then

went essentially into all phases of the software development process from the very start from the

planning where we have to figure out which requirements we need and in that early phase we

can already identify many problems that may emerge at a later point and fix them by having

right communications with the people who actually want to use the software so that's really really

important if you don't do that you will lose a lot of time effort and in a business case this

also means money. The next thing that we were then starting to do is based on the requirements we then

went over into the system planning tried to look at few ideas on system architectures looked into

design patterns that help us with the implementation up to the actual implementation and coding

guidelines and then once you implement said something you also have to test so in the last

lecture we quite extensively talked about where to test at what levels to test and what testing is

possible really from unit tests to component tests up to whole system tests and then you're still not

done because you might want to run an alpha beta test with a lot of testers so this is with growing

maturity you do more testing and also have a wider group of testers up to the point that you then

really release the system and even then there might be still bugs that you have to treat and

therefore you will have to adopt your job at your software even after the first release. This whole

idea leads us to the idea of software evolution in contrast to other products that are built in a

factory and like a chair you deliver the chair and then your customer has to live with it but

there is it's just a product if it breaks then they have to buy a new chair. With software it's

a bit different because software can grow pretty old and then you have to change it and therefore

we will talk today about the software evolution how to deal with the software evolution how to

deal with changes how to perform maintenance and how to deal with legacy systems because actually

our software can get very very old so there is software that is still in use one of the oldest

is the Sabre airline reservation system that has been established in the 1960s or also the IRS

individual master file and business master file that is used like for for taxation purposes has

also implemented in the 1960s and it's still in use. Also Word is a very very old system. Word's

first release date is in 1983 if you look at today's version of Word there is only faint

similarity with what has been released in 1983 in particular yeah so this was really

this was only on on text displays yeah now you have what you see is what you get interfaces you