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by bob1029 1220 days ago
If mass storage were free, then everything would be append-only by default. There would be no excuse to not do this.

A major benefit of append-only is that your writes are always ideal for whatever storage medium. Especially magnetic or tape. Combine append-only with batching of transactions (i.e. across 1-10 milliseconds at a time), and you can write multiple txns per disk I/O operation (assuming txn size < storage block size).
2 comments
DrSAR 1220 days ago
Isn't information retrieval potentially more costly if you have to search over a larger sea of useless blocks. Certainly is the case in my garage+house where I can now store way more than I ever could in previous stages of my life.
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bob1029 1220 days ago
The root should be locatable in ~constant time. If you use something like the splay tree, the most recently-used/modified/inserted data remains near the hotter side of the log. There is no linear scanning aside from initial bootstrap in an approach like this.

You can search for some comments I made recently about an append-only database scheme.

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kragen 1220 days ago
what if you accidentally wrote your private key, photos of your nude boyfriend, or evidence of a crime to your mass storage
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sharkjacobs 1220 days ago
Then you would delete it

> everything would be append-only by default

doesn't mean everything is permanently etched into stone or written on the blockchain, it just means that "by default" everything you write is written to a new block[1], instead of having to free up old blocks to reuse and keep track of which blocks of storage are available

[1]"block" is just meant as a generic unit of storage, I'm not trying to say anything about actual drive blocks and implementation details

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sn0wf1re 1220 days ago
Even if it is etched in stone (or laser blasted into crystal), nothing a chisel and a hammer can't undo. :)
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bitwize 1220 days ago
The blocks with those would be scribbled over and invalidated.

Do you know why ASCII 0x7f is DEL? Paper tape is write-once. To indicate a deleted character, it was conventional to punch holes in all bit positions -- 0x7f on a 7-bit punch.

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kragen 1220 days ago
excellent point
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