Please answer from scratch do not copy and paste and also add links to websites you use for referencing and plz answer all questions and I don't want any existing solutions from this platform. thank you. Please you may skip question 1.2 as i do not have any details

Q.1.1 Discuss the main difficulty that a programmer must overcome in writing an operating (10) system for a real-time environment. (10) Q.1.2 Explain the function of the Page Map Table in all of the memory allocation schemes described in this chapter that make use of it. Explain your answer by describing how the PMT is referenced by other pertinent tables in each scheme. Q.1.3 Differentiate between multiprogramming and multiprocessing. (10) (10) Q.1.4 Early versions of UNIX were available only with a command-driven interface. In more recent years, graphical user interfaces became popular. Explain why these GUIs made an impact on the popularity of this operating system. Q.1.5 Discuss the following: i. The cause of thrashing? (5) ii. How does the system detect thrashing? (5) Once it detects thrashing, what can the system do to eliminate this