Computer Algebra System
Attached below is a book covering all the basic commands and examples of all the softwares mentioned above and a file which has some high level exercises done on the basis of it which is quite sufficient for learning them inside out. Working with softwares like MATLAB, Maxima, Mathematica, Maple,R require basic knowledge and ample practise commands .
Computer System Architecture
Operational Research is one such subject you will find least material about. Rare courses have this subject in graduation but in post graduation one or two papers of this subject stands compulsory. I have attached here syllabus of OR at graduation level so as to give the idea of topics which forms the base of the subject and also the most recommended book by Handy A.Taha . It has ever growing scope if one can be well versed in it then there are higher chances of opportunities than all the other conventional fields like Maths, computer science.
Real Analysis for Bsc Mathematical sciences 4thsem
Bartle and Sherbhert is one of the best books of analysis , very helpful in courses like B.Sc Maths, Mathematical sciences , physical sciences and also recommended for several pg entrances.It gives you a very clear idea of the topics , has compact content and anyone who has the curiosity to know and understand real numbers inside out will find it really cool.