todo

linux 系统控制硬盘旋转和停止的程序（spin down/up）

TODO (as of noflushd version 2.6)

* Per-device bdflush parameters. [kernel]

  For saner handling of multiple disks a kernel patch is needed that allows 
  for separate bdflush parameters on each device.
  
* Improve web site.

  Duh! Doomed to be a never ending work in progress, see
  http://noflushd.sourceforge.net). Contributions welcome.
  
* SCSI spinup. [kernel]

  The Linux IDE driver has the nice property of trying to spin up a disk
  if an access fails. SCSI leaves it to the user instead. We cannot trap
  reads or writes that haven't yet completed from userland though (at least
  not without sard). Furthermore, we cannot issue a spinup ioctl that will
  'overtake' the first rw request on the request queue. This, however,
  would be needed to insure that the first rw request on a spun down disk
  doesn't fail. Mimicking the IDE behaviour with a kernel patch for SCSI
  looks like the better option, but then the SCSI midlayer is full of
  pitfalls. (Think of request queues with a maximum length of one request.
  *shudder*)

* Better IPC. [noflushd, long term (3.0)]

  The current way of changing noflushd behaviour at runtime sucks. Some
  advanced form of IPC would be much preferred, eg. a user app that
  communicates with the noflushd daemon via a local socket/named pipe
  to update and query its parameters.

* Backoff scheme on zero spindown times. [noflushd, 2.x]

  When we detect that a disk spins back up immediately, increase its timeout
  value to prevent too many bogus spinup cycles when things go severely wrong.
  (Suggested by Joey Hess.) [Shouldn't be too difficult to implement. The
  tricky part is finding a clever heuristic that modifies the timeout sanely
  in all cases. I've spent some time on this issue, and haven't come up with
  a satisfying solution yet. Suggestions welcome!]

* LSB compliant init skript. [noflushd, 2.x]

  Hopefully this finally provides a standard way to install init skripts and
  rc symlinks on all distributions.