FILESYSTEMS
Journaling Filesystems: How ext4 Survives a Crash
Pull the power mid-write and a naive filesystem corrupts. A journal is the write-ahead log that lets ext4 come back consistent — by promising to do work before actually doing it.
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filesystems
5 postsLINUX
The VFS: How 'Everything Is a File' Actually Works
The same read() works on ext4 files, /proc fictions, sockets, and pipes because Linux routes every file operation through one dispatch layer. The VFS is the kernel's biggest interface — and its object model is worth stealing.
DATABASES
Write-Ahead Logging: The Only Trick Durability Has
Every database, filesystem, and message broker converges on the same move: append the intention to a sequential log, fsync, then update the real structures whenever. WAL is one idea wearing a dozen names — and its failure modes repeat too.
SYSTEMS
SSD Internals: Why Your Disk Is a Small Computer That Lies
Flash can't overwrite in place, erases in giant blocks, and wears out per cell — so every SSD runs a translation layer that remaps, garbage-collects, and levels wear behind your back. Write amplification, TRIM, and the cliff at 90% full, explained.
SYSTEMS
RAID: What It Protects, What It Doesn't, and the URE Math
RAID levels are three ideas — stripe, mirror, parity — composed. The interesting parts are the failure math: why RAID 5 rebuilds fail at modern disk sizes, what the write hole is, and why RAID is not backup, mathematically.