According to chat GPT the forward delta approach is common because it can be implemented purely append only, whereas reverse deltas require the last snapshot to be mutable. This doesn't work well for backup tapes.

Do you also think that the forward delta approach is a mere historical artifact?

Although perhaps backup tapes are still widely used, I have no idea, I am not in this field. If so the reverse delta approach would not work in industrial settings.

Yes, the deduplicated approach is superior, if you can accept requiring dedicated software to read the data or can rely on a file system that supports it (like Unix with hard links).

I'm looking for a cross-platform solution that is simple and can restore files without any app (in case I didn't maintain my app for the next twenty years).

I'm curious if the software you were working on used proprietary format, was relying on Linux, or used some other method of duplication.

The idea is:

The latest backup (timestamped) always contains a full copy of the current source state.

Any previous backups are stored as deltas: files that were deleted or modified compared to the next (newer) version.

There are no version numbers — just timestamps. New versions can be inserted naturally.

Each time you back up:

1. Compare the current source with the latest backup.

2. For files that changed or were deleted: move them into a new delta folder (timestamped).

3. For new/changed files: copy them into the latest snapshot folder (only as needed).

4. Optionally rotate old deltas to keep history manageable.

This means:

The latest backup is always a usable full snapshot (fast restore).

Previous versions can be reconstructed by applying reverse deltas.

If the source is intact, the system self-heals: corrupted backups are replaced on the next run.

Only one full copy is needed, like a versioned rsync mirror.

As time goes by, losing old versions is low-impact.

It's user friendly since the latest backup can be browsed through with regular file explorers.

Example:

Initial backup:

latest/ a.txt # "Hello" b.txt # "World"

Next day, a.txt is changed and b.txt is deleted:

latest/ a.txt # "Hi" backup-2024-06-27T14:00:00/ a.txt # "Hello" b.txt # "World"

The newest version is always in latest/, and previous versions can be reconstructed by applying the deltas in reverse.

I'm curious: has this been done before under another name? Are there edge cases I’m overlooking that make it impractical in real-world tools?

Would love your thoughts.

Comments URL: https://news.ycombinator.com/item?id=44408821

Points: 12

# Comments: 26

Reflecting, I suppose that businesses relying on Php/Laravel or Ruby are probably still enjoying simple SSR development. I've personally transitioned to Java and then .NET, and haven't seen SSR since. Which corner of software are you in, where you see SSR still being dominant?

It seems like a big deal to me and the entire shift is an indicator of how much the IT community is behind front end clients talking to a separate back end. Server side rendering is no longer considered normal. Server site rendering now means something entirely different. It is about running your frontend code on the back end, So you still have the separation, but instead running it on the same machine. Now the same ui code has to be compatible with two different run times. This is much, much more complex than traditional server side rendering.

I'm glad we now have things like single page apps and client site interactive applications, because some apps were really not possible with server side rendering unless with a lot of Jquery hackery that quickly becomes unmaintainable...

However, I do think that front end technologies are overused, so I agree with the author, And I also think this is objectively a contrarian opinion, considering my initial point.

Comments URL: https://news.ycombinator.com/item?id=37088579

Points: 3

# Comments: 1

- copying a database from production to local for bug reproduction/fixes - inserting seed-data into the local database - creating a migration after changing records - applying the migration - rolling back the migration - running a tool to copy configuration from a keyvault - running the end to end tests - generate certificates - set up an ssh tunnel to a remote server or database

All of these things are part of the development process, and cannot be part of the build system. Each of them has their own commands and tools.

All developers need to easily be able to do these things, without asking help each time, or learning the syntax of each command.

One easy way is to stuff all of them in a task runner with simple aliases. Another could be writing a document that you can copy/paste from. I prefer a task runner, since you can memorize the alias and work from the terminal without looking things up.

Use with your own OpenAPI Key.

Never google a CLI command again :-)

Comments URL: https://news.ycombinator.com/item?id=35162262

Points: 2

# Comments: 1