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2023#

  • in CS
  • 11 min read

SDLC methodology

The abbreviation SDLC stands for Software Development Life Cycle. It is frequently used in technology to refer to the entire process of technology innovation and support.

In software engineering, a software development process or software development life cycle is a process of planning and managing software development. It typically involves dividing software development work into smaller, parallel, or sequential steps or sub-processes to improve design and/or product management.

Most modern development processes can be vaguely described as agile. Other methodologies include waterfall, prototyping, iterative and incremental development, spiral development, rapid application development, and extreme programming.

  • in CS
  • 8 min read

Abstraction & Virtualization

In software engineering and computer science, abstraction is the process of generalizing concrete details, such as attributes, away from the study of objects and systems to focus attention on details of greater importance. Abstraction is a fundamental concept in computer science and software engineering, especially within the object-oriented programming paradigm.

In computing, virtualization (refer to IBM, AWS) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, storage devices, and computer network resources.

  • in c, elf
  • 12 min read

C variables representation in ELF 1 - Sections

Previously, we've used gcc -S to stop assembling and gcc -c to stop linking, and explored C variables representation in assembly(gcc -S) and object(gcc -c).

The symbols in the intermediate object file (vars-section.o) are waiting to be relocated and resolved to determine their actual virtual address. It's the linker's turn.

After linking, all object files (*.o) are linked into one ELF. By default, it links dynamically and the type of outcome is DYN (position-independent executable file).

  • in c
  • 9 min read

C Memory Order(Sequential Consistency)

The "happens before" relation is the only possible way to reason about timing between different threads. It is only established through synchronization that uses either atomic objects or very specific C library functions.

An atomic object can be used to synchronize two threads, if one thread writes a value and another thread reads the value that was written. Operations on atomics are guaranteed to be locally consistent.

Sequential consistency is the default consistency model for atomics, but not for other C library functions. It additionally assumes that all corresponding synchronization events are totally ordered.

  • in c, cpp
  • 13 min read

volatile in C/C++

volatile (computer programming) - Why is volatile needed in C?

volatile in C actually came into existence for the purpose of not caching the values of the variable automatically. It will tell the compiler not to cache the value of this variable. So it will generate code to take the value of the given volatile variable from the main memory every time it encounters it. This mechanism is used because at any time the value can be modified by the OS or any interrupt. So using volatile will help us accessing the value afresh every time.