11/01/10

Daemons (Unix)/ services (Windows)
- runs in background
- often started at boot time and terminated on 
  system shutdown
- provide services to other processes rather than 
  directly communicate with user

Daemon
  - sits idle  until an event occurs ("listening")
  - then it handles that event

Examples of daemons
  - ftpd, lpd, httpd, inetd

Request handling
  1. Read and parse the HTTP request
  2. Translate the pathname in the requested URL to a 
     filename
  3. Check that the request is allowed
      - authentication
      - authorization
  4. Construct the response
      - content handler
  5. Transmit the response to the client
  6. Record info about the request and response in a log

Handling multiple requests
  - queue
  - concurrency

Apache Web Server
  - a patchy server
  - version 1.3
  - version 2.0 (2.2)
  - 1999, Apache Software Foundation

Alternatives
  - Microsoft Internet Information Services (IIS)
  - specialised servers

Or...
  - hosting company
  - colocation