January 2, 2026
Sync wars: nostalgia vs now
The rsync algorithm (1996) [pdf]
A 1996 file-sync breakthrough has coders nostalgic—and arguing over 'real work'
TLDR: A 1996 paper explains rsync, a way to sync files by sending only the changes, and it still underpins how backups and updates work. Comments split between nostalgia-fueled praise for “real engineering” and pushback to respect modern fields—proof that simple, lasting ideas still spark big feelings.
An old-school classic just got a fresh round of applause: the 1996 paper that explains rsync, a clever way to update a file by sending only what changed over a slow connection. Think dial‑up days, but smarter. The ANU tech report lays it out in clear, no‑fluff language.
Comments erupted into a mix of misty-eyed respect and spicy gatekeeping. One camp shouted, this is real computer science — elegant, practical, and still powering backups, mirrors, and software updates today. User doodlesdev praised how “well‑written” it is and wished more engineers tackled “real problems” like efficient file syncing. Others clapped back: don’t dunk on modern work; fundamentals and today’s AI and apps can coexist. The mood: salute the classics, skip the elitism.
The humor was premium. “I rsync my feelings,” joked one, while another mimed dial‑up noises and thanked this algorithm for saving their phone bills. Memes crowned rsync as Git’s thrifty older cousin and roasted bloated apps that re‑download everything. The mini‑flame war peaked when someone claimed today’s devs only copy‑paste, prompting educators to show students still learn these basics. Final vibe check: timeless tech, timeless drama — and a PDF that still slaps.
Key Points
- •The report introduces the rsync algorithm for synchronizing files across machines connected by low-bandwidth, high-latency links.
- •rsync avoids sending entire files by identifying segments in the source that match parts of the destination and referencing those instead of retransmitting them.
- •Only non-matching segments are transmitted verbatim, enabling efficient reconstruction of the source file on the receiver.
- •Traditional diff methods require both files to be on the same machine; rsync computes necessary differences without co-locating both files.
- •The algorithm performs best when files are similar but remains correct and reasonably efficient even when they differ significantly.