Omar Morsy

Database Design: From Novice to Professional [Ch.3: Initial Requirements and Use Cases]
In this chapter we will foucs on the Analysis part but in the abstract world focus on what the user can do in our system. Remember the 4 process thinking, Now we consider part of the first step from real-world problem to eventual real-world solution ...
Aug 8, 202218 min read
Database Design: From Novice to Professional [Ch.2: Guided Tour of the Development Process]
In the previous chapter we talked about how bad design can lead to problems in the future in the two incoming chapters we will talk about the process you can follow that may help you in designing your database. before we start we need to know that f...
Aug 8, 202210 min read
Omar Morsy
10 posts
Software engineer | Top 1% on leetcode
Database Design: From Novice to Professional [Ch.1: What Can Go Wrong]
Designing a poor database can lead to many problems that may not show at the time of creation of the database but will definitely show in the future. So in this chapter, we will show examples drawn from real life to illustrate some very basic types o...
Mar 6, 20226 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.8: Event-based Concurrency (Advanced)]
Event-based Concurrency (Advanced) threads are not the only way to write concurrency apps, a different style of concurrent programming is often used in both GUI-based applications and some types of internet servers This style, known as event-based co...
Nov 24, 20216 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.7: DeadLock]
Common Concurrency Problems we can classify that there are 2 types of bugs in concurrency code 1) Non-Deadlock Bugs 2) Deadlock bugs Non-deadlock atomicity violation bugs and order violation bugs Atomicity-Violation Bugs The first type of problem enc...
Nov 23, 202111 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.6: Semaphores]
Semaphores One can use semaphores as both locks and condition variables. A semaphore is an object with an integer value that we can manipulate with two routines; in the POSIX standard, these routines are sem wait() and sem post()1 . Because the initi...
Oct 20, 202113 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.5: Condition Variables]
Condition variables A condition variable is an explicit queue that threads can put themselves on when some state of execution (i.e., some condition) is not as desired (by waiting on the condition); some other thread, when it changes said state, can t...
Oct 20, 202110 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.4: Locked Data Structures]
In this chapter we will see couple of famous data structures that we will convert them to be a concurrent data structure and at the end, we will see some tips when you develop your own concurrent data structure You should always think about your lock...
Oct 15, 20219 min read
Operating Systems: Three Easy Pieces [Concurrency Ch.3: Locks]
Locks When you have a region of code that is a critical section, and thus needs to be protected to ensure correct operation, locks are quite useful. As an example, assume our critical section looks like this, incrementing shared variable: balance = b...
Oct 15, 202119 min read