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| Linux System Programming Techniques & Concepts |
The intention of this course is to make you ready for System programming Technical interviews, interview level - from Beginner to Intermediate. This course is for (future) Developers, not for testers or system Administrators.
I choose to create this course to fill the gap between novice/beginner and intermediate/Advanced Programmers. This course assumes that you are at-least above average in programming (in any programming language, but preferable in C/C++) - know memory allocations, all kinds of loops, function calls, pointers etc. In this course, I wont teach C/C++ (there are already many courses on it online), but would teach programming techniques and low level details regarding how C program works behind the scenes - All topics very important from interview point of view. My Target is to grow this course into Linux/C Bible.
Yet, I always feel, you need to outsmart your fellow colleagues in this era of stiff competition, and therefore, I tried this attempt to present you the wisdom and knowledge which is of utmost importance for a programmer. I have seen though students could write good C/C++ programs, yet they lacks the clarity on how one should write better organized, Manageable, extensible and programmable codes in the form of libraries. For example, Student too good in competitive programming, yet do not know how to write a simple Makefile, reason being, Academics do not teach and students do not care to learn.
In this course, I will cover the topics related to creating Linux System Libraries (release 1) with Advanced language agnostic Programming Concepts (release 2) which can be well applied if you happen to become a programmer in other languages tomorrow.
The Concepts like MultiThreading, Thread-Synchronization, Socket Programming, IPCs etc demands a separate course on each topic altogether. Currently, I have a course on IPC, pls check it out. These topics are out of scope of this course.
The Course shall be delivered into two Releases :
Release 1 Building and Managing a Library : This covers basics regarding how one should create and organize his code as a Library.
Release 2 Memory Management Concepts : This covers Advance concepts on Linux Memory Management specifically. Please check Table of Contents for more info.
Why you should *NOT* do this course ?
1. Please Excuse this course if you are ultimate beginner in C programming !!
2. There is no point of doing this course if you don't like hitting keyboard, and lazy enough to watch lecture VDOs only
3. If you want everything cooked and served on your plate.
Course Pre-requisite :
- Above Beginners Level in C/C++ programming
- Good to have basic OS knowledge
- Zeal to excel and Code
No Third Party libraries
Whatever logic you implement, you need to implement it from scratch. Like all my other courses, this course do not suggest taking help of any third party library to get the jobs done. Use of external libraries completely defeats the purpose of the course.
Warning : This course has auto system-generated subtitles which may not be perfect. Please disable subtitles as per your convenience.
Curriculum :
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Release 1 Building and Managing a Library
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Section 1 : Introduction to Libraries
- What is Library
- Relationship between Library and Application
- Ex : Doubly linked list as a Library
- Quick Compilation Steps
- Summary
Section 2 : Header Files
- Relationship between Source and header files
- Text Substitution Method
- Text Substitution Method - Example and Demo
Section 3 : Preprocessing Directives
- Problem of Duplicate inclusion of Hdr files
- Pre-processing Directives
- Solution to Duplicate inclusion of Hdr files
Section 4 : Correct way of Using Structures and Functions
- Structures - Define and Use thumb Rule
- Functions - Declare and Use thumb rule
- Problem of Recursive Dependency
- Solution to Recursive Dependency
Section 5 : Creation of Static and Dynamic Libraries
- Resuming with Doubly Linked List Library
- Quick Creation of Static and Dynamic Libraries
- Linking with Static Library
- Linking with Dynamic Library
Section 6 : Building using a Makefile
- What are Makefiles and why do we need it
- Functions of Makefile
- Makefile Dependency tree
- Steps of Writing a Makefile
- Assignment on Makefile
Section 7 : Run-time Programmable libraries
- What are Programmable Libraries ?
- Steps to Program the libraries
- Registering of the callbacks with Libraries
- key_match callback
- comparison_fn callback
- Delegation of Application specific operations to Libraries
Section 8 : Writing Iterators using Macros
- What are Iterative Macros ?
- Why we need Iterative Macros ?
- How to Write Iterative Macros - For Trees and Linked Lists
- Exercises
Section 9 : Glue Based Libraries and Data structures
- What are Glue Based Libraries ?
- Introducing Glthreads - A Glued Linkedlist
- Glthreads Vs Traditional Linked List
- Structure field offset
- GLThread Operations
- Code Walk
- GLThread Benefits
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Release 2 Memory Management Concepts
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Section 10 : Memory Layout of Linux Process
- Virtual Memory Basics
- Memory Layout of Linux Process
- Example : Memory Layout of Linux Process
- Exercise on size command
Section 11 : Stack Memory Management
- Stack Memory Basics and Contents
- Stack-Overflow and Prevention
- Stack Memory Corruption
- Common Cpu Registers
- Procedure Call Mechanism - Step by Step
- Purpose of Base Pointer register (ebp)
- Procedure Return Mechanism - Step by Step
- Lab session
Section 12 : Heap Memory Management
- Introduction and Goals
- How Malloc Works
- Top of Heap Memory region - break pointer
- Heap Memory Mgmt Sys Calls - brk and sbrk
- Meta and Data Blocks
- How free() works
- Block Splitting
- Block Merging
- Memory Illness - Problem of Fragmentation
Section 13 : Concept of Paging
- Introduction to Paging
- Byte Addressable Memory
- 32 bit and 64 bit Machine Architecture
- Address Bus and Data bus
- Physical Vs Virtual Address
- Physical Memory Frames
- Virtual Address Composition
- Page Table
- Paging In Action
- Shared Physical Memory
Section 14 : Multilevel Paging
Section 15 : Demand Paging
Section 16 : Memory Management for Multi-threaded Process
**TOPICS TO BE ADDED**
Section 18 : Understanding four stages of Compilation
- Four stages of C/C++ Compilation
- How Dynamic Library works ?
- Dynamic Linking : Linking with Dynamic Library
- Comparison - Static Vs Dynamic Linking
Section 19 : Structure Padding in C
- What is Structure Padding ?
- Why Padding is done ?
- Disable Padding
Section 20 : Hidden Structures in C
- What are Hidden Structures ?
- Access hidden Structures
- Opaque Pointers
Section 21 : Endianess and Byte Order
- Big-endian and Little Endian Machines
- Host Byte Order
- Network Byte Order
- htonl() and variants
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The intention of this course is to make you ready for System programming Technical interviews from beginners to upto 8-9 yrs of experience.
Q. What are the frequently asked questions by interviewers in a technical round when someone writes C/C++/System Programming language on their resume?
Answer : If i am interviewer , what questions i would ask depends on his no of years of experience in C.
1–3 yrs of experience — I would have asked:
- Double pointers
- design a Macro to return the size of structure
- Two Dimensional Arrays, passing and returning arrays from a fn
- Different stages of C program compilation
- how fork() works
- What are various ways to debug memory corruptions.
- various IPCs
- Heap and Stack memory based Question
4–6 yrs of experience - I would have asked:
- How memory is allocated by the OS
- Internal and external fragmentation, what can be done to avoid it
- System calls, strace()
- Trade-of of one IPC over other
- various ways to communicate with kernel and comparison
- Data (De)Serialization in C
- RPC in C
- callbacks advanced application
- typedef Vs #define
- Generic programming in C using macros
- Thread Synchronization
- Heap and Stack memory based Question
7+ yrs of experience - I would have asked
- Have you designed any system module to solve any problem
- Design thread library 0 what functionalities would you incorporate in and how ?
- What are Dos and Dont’s for writing a robust and flexible library
- How to write generic code in C
- Various ways to implement timers in C, and comparison of approaches
- How Interrupts work ?
- IPCs and comparison
- How would you convert a C code to C++ and vice versa
- How to write a tool to detect memory leaks, Or garbage collection
- Design your own memory allocation tool. Why would you write your own memory allocation scheme ?
- When to go for Multi-process design over Multi-threaded design and vice versa
- How ValGrind tool works
- In production code, would you favor recursive but simple logic, Or Non recursive but complex logic, and why ?
If you analyse the pattern,
Candidate with 1–3 yrs of experience, I would chose to ask more of a direct and straightforward Questions.
Candidate with 4–6 yrs of experience, I would chose to ask more advanced technical C Question plus some comparison of approaches based Questions
Candidate with 7+ yrs of experience, I would chose to ask more of a design and Analysis based Question.
Note that, since Question pertains to C and System Programming, so i have not mentioned Data structures and Algorithms.
Who this course is for:
- Students who have basic knowledge of C/C++ programming
- Warning : Not for Absolute beginners in Programming
- Who want to take their programming Skills from Beginner to Professional Level
- Final year students looking to crack the Interview Questions on OS, C programming
- Get the course
