# eswaraprasath802/learn-linux-internals-through-programming architecture

> Architecture diagram of the GitHub repository eswaraprasath802/learn-linux-internals-through-programming, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-08-14). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/eswaraprasath802/learn-linux-internals-through-programming
- Repository: https://github.com/eswaraprasath802/learn-linux-internals-through-programming

## Overview

#### Purpose and Entry Points
This is a C systems-programming repository centered on small, standalone demonstrations of OS concepts: process creation, threads, synchronization, IPC, scheduling, memory allocation, device access, signals/alarms, timer interrupts, and a tiny filesystem. There is no README describing a unified application. `main.c` is the likely general entry point, while many concept files may be independently compiled or contain their own demonstrations.

Paths: `main.c`, `Makefile`, `samples.c`

#### Process, Thread, and Identity Model
Process and execution-context examples cover forking, PIDs, waits, and POSIX threads. These define the repository’s concurrency boundary between address-space processes and in-process threads.

Paths: `fork.c`, `pid.c`, `wait.c`, `thread.c`, `pthread.c`

#### Synchronization Primitives
Multiple files implement or demonstrate competing synchronization mechanisms: mutexes, spinlocks, binary/counting semaphores, reader/writer-style locking, and atomic operations. These components are the core coordination layer for shared-state examples.

Paths: `mutex.c`, `spinlock.c`, `atomic.c`, `binarysemaphore.c`, `countsemaphore.c`, `rmlock.c`

#### IPC and Producer/Consumer Flow
Named sender and receiver programs indicate a pipe-based message flow: a sender writes data to a pipe and a receiver consumes it. Semaphore and mutex examples likely support related producer/consumer coordination patterns, but remain separate source-level demonstrations unless linked by the build.

Paths: `sender_pipe.c`, `receiver_pipe.c`, `semaphone.c`

#### Scheduling and Time/Event Simulation
Scheduling, alarms, and simulated timer interrupts model control flow driven by time or kernel-like events. These files likely demonstrate ordering, preemption concepts, or periodic event handling rather than production scheduling infrastructure.

Paths: `sheduler.c`, `timer_irq_sim.c`, `alarm.c`

#### Memory and Fault Handling
Custom allocation and page-fault examples isolate memory-management behavior. The allocator is a material ownership boundary: callers request and release memory through repository-defined logic rather than only the C runtime allocator.

Paths: `myalloctaor.c`, `pagefault.c`

#### Kernel-/Device-Like Interfaces and Storage
Character-device and filesystem examples represent the lowest-level interface boundary in the repository. `mychardev.c` likely models device-file interaction; `tinyfs.c` and the `tinyfs` artifact represent a compact filesystem implementation or executable.

Paths: `mychardev.c`, `tinyfs.c`, `tinyfs`

#### Runtime and Infrastructure
The repository targets a native C/POSIX-style runtime, with likely dependencies on libc and OS facilities such as `fork`, pipes, signals, file descriptors, and pthreads. `Makefile` is the build orchestration point; no external cloud services, databases, web runtime, or network service dependencies are evident from the tree.

Paths: `Makefile`, `doubt.c`, `main.c`

Main entry points: [`Makefile`](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/Makefile) (Makefile), [`thread.c`](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/thread.c) (Thread demos), [`sender_pipe.c`](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/sender_pipe.c) (Pipe sender), [`tinyfs.c`](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/tinyfs.c) (Tiny filesystem)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_build["Build & Entry"]
  node_makefile["Makefile<br/>build orchestration"]
  node_main["Main demo<br/>C entry point<br/>[main.c]"]
  node_samples["Samples<br/>standalone demos<br/>[samples.c]"]
end

subgraph group_concurrency["Concurrency"]
  node_processes["Process demos<br/>fork, PID, wait<br/>[fork.c]"]
  node_threads["Thread demos<br/>POSIX threads<br/>[thread.c]"]
  node_pthread["Pthread demo<br/>POSIX thread API<br/>[pthread.c]"]
  node_sync{{"Synchronization<br/>shared-state primitives<br/>[mutex.c]"}}
end

subgraph group_ipc["IPC &amp; Events"]
  node_sender["Pipe sender<br/>IPC producer<br/>[sender_pipe.c]"]
  node_receiver["Pipe receiver<br/>IPC consumer<br/>[receiver_pipe.c]"]
  node_scheduler["Scheduler demo<br/>scheduling simulation<br/>[sheduler.c]"]
  node_timer(("Timer IRQ simulation<br/>periodic event source<br/>[timer_irq_sim.c]"))
  node_alarm(("Alarm demo<br/>signal timer<br/>[alarm.c]"))
end

subgraph group_memory["Memory &amp; Low-Level I/O"]
  node_allocator["Custom allocator<br/>memory ownership<br/>[myalloctaor.c]"]
  node_pagefault["Page-fault demo<br/>memory fault handling<br/>[pagefault.c]"]
  node_chardev["Character device<br/>device-file interface<br/>[mychardev.c]"]
end

subgraph group_storage["Storage"]
  node_tinyfs_source["Tiny filesystem<br/>filesystem implementation<br/>[tinyfs.c]"]
  node_tinyfs_binary["tinyfs<br/>filesystem executable"]
end

node_posix{{"Native POSIX runtime<br/>OS and libc facilities"}}

node_makefile -->|"builds"| node_main
node_makefile -->|"builds demos"| node_samples
node_makefile -->|"builds"| node_tinyfs_binary
node_tinyfs_source -->|"compiled into"| node_tinyfs_binary
node_main -->|"uses"| node_posix
node_processes -->|"fork and wait"| node_posix
node_threads -->|"threads"| node_posix
node_pthread -->|"pthread API"| node_posix
node_threads -.->|"coordinates shared state"| node_sync
node_sync -->|"runtime primitives"| node_posix
node_sender -->|"pipe messages"| node_receiver
node_sender -->|"pipe I/O"| node_posix
node_receiver -->|"pipe I/O"| node_posix
node_scheduler -.->|"driven by ticks"| node_timer
node_timer -->|"timing events"| node_posix
node_alarm -->|"alarms and signals"| node_posix
node_allocator -.->|"memory behavior context"| node_pagefault
node_chardev -->|"device-file access"| node_posix
node_tinyfs_source -->|"file and device I/O"| node_posix

click node_makefile "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/Makefile"
click node_main "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/main.c"
click node_samples "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/samples.c"
click node_processes "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/fork.c"
click node_threads "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/thread.c"
click node_pthread "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/pthread.c"
click node_sync "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/mutex.c"
click node_sender "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/sender_pipe.c"
click node_receiver "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/receiver_pipe.c"
click node_scheduler "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/sheduler.c"
click node_timer "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/timer_irq_sim.c"
click node_alarm "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/alarm.c"
click node_allocator "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/myalloctaor.c"
click node_pagefault "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/pagefault.c"
click node_chardev "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/mychardev.c"
click node_tinyfs_source "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/tinyfs.c"
click node_tinyfs_binary "https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/tinyfs"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_makefile,node_main,node_samples toneBlue
class node_processes,node_threads,node_pthread,node_sync toneAmber
class node_sender,node_receiver,node_scheduler,node_timer,node_alarm toneMint
class node_allocator,node_pagefault,node_chardev toneRose
class node_tinyfs_source,node_tinyfs_binary toneIndigo
class node_posix toneNeutral
```

## Components

### Build & Entry

- [Makefile](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/Makefile): build orchestration · `Makefile`
- [Main demo](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/main.c): C entry point · `main.c`
- [Samples](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/samples.c): standalone demos · `samples.c`

### Concurrency

- [Process demos](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/fork.c): fork, PID, wait · Separate address-space and lifecycle demonstrations. · `fork.c`
- [Thread demos](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/thread.c): POSIX threads · `thread.c`
- [Pthread demo](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/pthread.c): POSIX thread API · `pthread.c`
- [Synchronization](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/mutex.c): shared-state primitives · Mutex, spinlock, atomic, semaphore, and reader/writer locking examples. · `mutex.c`

### IPC & Events

- [Pipe sender](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/sender_pipe.c): IPC producer · `sender_pipe.c`
- [Pipe receiver](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/receiver_pipe.c): IPC consumer · `receiver_pipe.c`
- [Scheduler demo](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/sheduler.c): scheduling simulation · `sheduler.c`
- [Timer IRQ simulation](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/timer_irq_sim.c): periodic event source · `timer_irq_sim.c`
- [Alarm demo](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/alarm.c): signal timer · `alarm.c`

### Memory & Low-Level I/O

- [Custom allocator](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/myalloctaor.c): memory ownership · Repository-defined allocation and release boundary. · `myalloctaor.c`
- [Page-fault demo](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/pagefault.c): memory fault handling · `pagefault.c`
- [Character device](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/mychardev.c): device-file interface · `mychardev.c`

### Storage

- [Tiny filesystem](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/tinyfs.c): filesystem implementation · `tinyfs.c`
- [tinyfs](https://github.com/eswaraprasath802/learn-linux-internals-through-programming/blob/master/tinyfs): filesystem executable · `tinyfs`

### Other components

- **Native POSIX runtime**: OS and libc facilities · Provides processes, pipes, signals, file descriptors, and pthreads.

## Connections

- Makefile → Main demo: builds
- Makefile → Samples: builds demos
- Makefile → tinyfs: builds
- Tiny filesystem → tinyfs: compiled into
- Main demo → Native POSIX runtime: uses
- Process demos → Native POSIX runtime: fork and wait
- Thread demos → Native POSIX runtime: threads
- Pthread demo → Native POSIX runtime: pthread API
- Thread demos → Synchronization: coordinates shared state
- Synchronization → Native POSIX runtime: runtime primitives
- Pipe sender → Pipe receiver: pipe messages
- Pipe sender → Native POSIX runtime: pipe I/O
- Pipe receiver → Native POSIX runtime: pipe I/O
- Scheduler demo → Timer IRQ simulation: driven by ticks
- Timer IRQ simulation → Native POSIX runtime: timing events
- Alarm demo → Native POSIX runtime: alarms and signals
- Custom allocator → Page-fault demo: memory behavior context
- Character device → Native POSIX runtime: device-file access
- Tiny filesystem → Native POSIX runtime: file and device I/O