Before Git, the Linux kernel developers used a version control system called BitKeeper.
BitKeeper was proprietary software, but Linux developers could use it for free for kernel development.
Then in 2005:
- Licensing conflicts happened
- Access to BitKeeper was removed for Linux developers
- The Linux kernel team suddenly lost the tool managing one of the world’s biggest software projects
This was a disaster.
The Linux kernel already had:
- thousands of files
- many developers
- patches arriving constantly
- changes from all over the world
Linus Torvalds needed a replacement immediately.
He did not like existing systems because they were:
- slow
- centralized
- hard to merge
- bad at handling large distributed development
So he decided to build his own system.
2. How Fast Git Was Built
This is one of the most famous parts of Git history.
The first version of Git was built in only a few days.
Core development timeline:
- Day 1–2: Basic object storage and hashing concepts
- Around Day 4: Could track file snapshots
- Around Day 10: Basic branching and commits worked
- Within about 2 weeks: Git became usable for Linux kernel development
That speed sounds impossible today, but several things made it possible:
Linus already understood:
- operating systems
- filesystems
- performance engineering
- distributed collaboration
- kernel development workflows
- low-level data structures
He was not experimenting randomly.
He already had a very clear mental model before writing code.
3. What Language Git Was Written In
Git was primarily written in:
- C
Why C?
Because:
- extremely fast
- direct filesystem access
- portable
- already used heavily in Linux
- minimal overhead
- efficient memory control
Git also used:
- shell scripting initially
- some Perl scripts in older tooling
But the core engine was C.
Today Git includes:
- C
- shell
- Perl
- Python
- Tcl/Tk
- some platform-specific code
But its heart is still mostly C.
4. The Mentality Behind Git
This is the most important part.
Git was not designed like a normal “application.”
Linus designed Git like a filesystem + cryptographic database.
His mentality was:
“Store everything as immutable content objects.”
That single idea shaped all Git architecture.
5. The Core Philosophy of Git
Most old version control systems stored:
- file differences
- centralized history
- sequential changes
Git instead stores:
- complete snapshots
- content-addressed objects
- immutable history
This was revolutionary.
Git thinks like this:
Project State → Hash → Stored Object
Not:
Edit A → Edit B → Edit C
That difference is enormous.
6. Git’s Most Important Idea: Hashing
Git uses cryptographic hashes.
Originally:
- SHA-1
Every file and object gets a unique hash.
Example:
e83c5163316f89bfbde7d9ab23ca2e25604af290
That hash identifies content.
Meaning:
- if content changes
- hash changes
So Git can detect:
- modifications
- corruption
- exact history relationships
This made Git:
- reliable
- fast
- distributed
7. Git Was Designed Backwards From Performance
Linus cared deeply about performance.
His priorities were:
- Speed
- Data integrity
- Distributed workflow
- Branching efficiency
- Merge capability
Not:
- pretty UI
- beginner friendliness
- enterprise features
That is why Git commands can feel difficult.
It was originally designed for kernel developers.
8. The Architecture of Git
Git internally stores objects:
Blob
Stores file contents.
Tree
Stores directory structures.
Commit
Stores:
- author
- timestamp
- parent commits
- snapshot reference
Tag
Named references.
Everything becomes objects.
9. Why Git Branching Is So Fast
In many older systems:
- branches copied files
In Git:
- branches are basically lightweight pointers.
A branch is almost just:
branch_name → commit_hash
That means:
- branch creation is nearly instant
- switching branches is fast
- merging is easier
This was a huge innovation.
10. Git Was Built for Distributed Development
Older systems often relied on a central server.
Git changed this.
Every developer gets:
- full history
- full commits
- full branches
- complete repository
Meaning:
- work offline
- no single point of failure
- easier collaboration
This was revolutionary in 2005.
11. How Linus Actually Built It
Linus usually builds software with this mentality:
Step 1 — Solve only the core problem
No unnecessary abstractions.
Step 2 — Make data structures efficient
Performance first.
Step 3 — Use small composable tools
Git originally had many tiny commands.
Step 4 — Trust powerful primitives
Instead of giant frameworks.
Step 5 — Optimize around real workflows
Not theoretical design.
This is very Unix-like thinking.
12. Early Git Was Extremely Rough
The first Git versions were:
- ugly
- command-line heavy
- poorly documented
- hard to use
Linus himself said he was not trying to make it pretty.
He only wanted:
- speed
- correctness
- distributed functionality
Later developers improved usability.
One major contributor was:
Junio Hamano
He became the long-term maintainer and helped Git mature into a polished tool.
13. Why Git Became Dominant
Git became dominant because it solved real engineering pain better than competitors.
Major advantages:
- fast branching
- powerful merging
- offline development
- integrity checking
- scalability
- distributed collaboration
This made it perfect for:
- open source
- large engineering teams
- internet-scale collaboration
Then platforms like:
- GitHub
- GitLab
- Bitbucket
accelerated adoption massively.
14. The Most Important Technical Insight
Git is not really “a source control app.”
Internally, it is closer to:
- a content-addressable object database
- plus graph relationships
- plus filesystem snapshots
That architectural decision is why Git still scales today.
15. Why Git Feels Complicated
Because Git exposes internal concepts directly:
- HEAD
- refs
- index
- detached HEAD
- rebasing
- object store
Linus optimized for:
- power
- flexibility
- speed
not beginner simplicity.
That tradeoff is still visible today.
16. The Deep Engineering Lesson From Git
Git teaches a major software engineering principle:
Great systems are often built from a few powerful primitives.
Git’s primitives:
- hashes
- immutable objects
- pointers
- graphs
- snapshots
From those few concepts, an entire ecosystem emerged.
17. Final Summary
Git was:
- created in 2005
- mainly built by Linus Torvalds
- written mostly in C
- initially usable within about 10–14 days
- designed under extreme pressure
- optimized for speed and distributed collaboration
The mentality behind Git was:
Simple primitives
+ immutable data
+ hashing
+ distributed architecture
+ performance-first engineering
That combination changed software development forever.
Top comments (0)