WebFund 2016W Lecture 11

Notes

In-class Notes

Lecture 11
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Databases

/var/spool/mail
  - where email is stored
  - one file per user

my mail inbox in /var/spool/mail/soma

Who accesses this file?
  - mail client
  - mail server

What happens if the mail server delivers mail while I'm going
through my email (deleting, filing)
 - unless you lock it, you lose mail, mail client will overwrite
   inbox and delete new messages
 - solution: lock the inbox
     create a soma.lock file
     (inside it has the process ID of the accessing process)

This is a bad idea that does not scale
Instead, use a database
 - concurrent access
 - data persistence