Re: [9front] Enabling a service

[Jacob Moody <moody@posixcafe.org>]

On 5/8/24 11:33, Frank D. Engel, Jr. wrote:
> When you perform a write, you send that write to the file server on the 
> remote system and it updates the block, generating the appropriate 
> hash.  If another client sends a write with a collision, the file server 
> handles it the same way it already would - the two are ultimately 
> processed in some order or another.
> 
> Each client system may have updated a locally cached copy of the block 
> with the same written data, but if the data did not match what was 
> generated on the file server because it was updated in the meantime, 
> then the hash on the client system will not match what the remote server 
> came up with.
> 
> Consequently, when it later tries to read that block again, the file 
> server sends it the hash that it has, which does not exist in the local 
> cache, so the client is forced to request the correct block from the 
> file server instead of using the locally cached copy.
> 
> Similarly, the other client performed its write and has yet another 
> different hash, since the server has the data from both clients.  When 
> that client tries to perform another read, its hash won't match either, 
> forcing it too to obtain the correct copy of the data from the file server.
> 
> Had only one of them been manipulating the data, then that one would 
> have the correct copy with a matching hash, so it would be able to use 
> its local copy.
> 
Thank you I see the full picture now, using the hashes for checking against
the server. It sounds like it would work as well as any central filesystem
does for multiple users.