mjk study log

Today, I will write a simple blog on my experience taking a KISA Information Security Engineer Certificate test and how I passed the theoretical test. What is the KISA Information Security Certificate (정보보안기사 자격증)?The KISA Information Security Certificate, issued by the Korea Internet & Security Agency, verifies that organizations in South Korea meet specific information security standards. It h..

What is hash collision?Hash collision happens when the different keys (inputs of the hash function) have the same hash value. Simply, it means the hash code is not unique. SSH & CodeWhen you log Into the server, you can realize that your current uid is col. This means you must use a col file to execute, but you can read col.c.  Let's look into the col.c file:In the main function, the first if st..

Useful tip) always use "man" to find the options:man  Web ServerTo connect to the internet from your computer, your browser needs to communicate to a web server over protocols like HTTP.  How do we create web servers? - there are several methods:python3 -m http.server [port] # python 3 server# http web server with npmnpm install http-serverhttp-server -p [port]# http web server with phpphp -S [a..

Useful tip) always use "man" to find the options: man Package Management You might have used "apt install" or "apt update" to download files or update the versions. As you can assume, apt is the command to manage packages. Then what's the difference between the commands "dpkg"? APT apt stands for "advanced package manager" high-level command-line interface apt is a newer version of "apt-get" apt..

Concurrency를 지키기 위한 3가지의 툴에 대한 노트입니다. * All the code below is a harmony code Before we start, it is important to mention Atomic Section IS NOT Critical Section Atomic Section (Mutex) Critical Section - one thread running among different processes - Single Thread: no other threads can run while running t1 - good for interlock instruction - one thread running within one process - multiple threads ..

Today, I am listing some of the basic concepts in Operating Systems. * Quick warning - this may be very simple. Program v. Process v. Thread Program: executable file that includes process instructions or code. When the program is loaded from the disk to the main memory (RAM) and executed by a processor, it becomes a process. Process: an instance of execution - running code. Includes resources li..