[TicklishTiger]

I would not trust this.

What I would trust:

A backup medium (SSD or whatever) which only allows writes to empty space. Unless a switch is manually switched from "write" to "update".

In "write" mode, it would only allow writing to empty space.

In "update" mode, it would allow writing everywhere.

I would leave it in "write" mode most of the time. For me, a typical SSD has enough space for years of incremental backups. If I should ever want to delete old backups, I would set it to "update" mode to do that and then set it back to "write" mode.

[creshal]

> A backup medium (SSD or whatever) which only allows writes to empty space. Unless a switch is manually switched from "write" to "update".

Why is your backup medium not encrypted?

[hulitu]

> Why is your backup medium not encrypted?

If you lose the key, you lose the backup.

[rich_sasha]

Is this also true for random OS churn etc? Basically when using the SSD as a “persistent cache”

[tinus_hn]

You could probably get a tape to work like this if you can prevent rewinding.

[compsciphd]

i.e. a log structured file system.

[compressedgas]

Specifically a WORM. Like Plan 9 had with Fossil and Venti or as in Foundation https://swtch.com/~rsc/papers/fndn/