On 27/09/10 12:41, Mark Morgan Lloyd wrote:
Henry Vermaak wrote:
The first of those can at least be initiated using a sync() call, and
it's reasonable to assume that a filesystem designed for the purpose
won't get screwed if the driver finds it can no longer talk to the
storage device. However if the storage device itself is susceptible to
errors caused by power removal that is far more sinister.
The only delay I can see (after fsync) would be due to the hardware
cache of the disk in use (or a defective drive). On linux you can call
hdparm to flush on-disk caches.
But is hdparm fully supported by external Flash cards, and does it
return before or after data is guaranteed to be filly committed?
This is a red herring (sorry, my mistake). Compact flash cards (and
other removable media) are block devices, they have firmware that do
this flash to block emulation. I realise now that Michael meant that
some cf cards have crappy firmware that can't handle power cuts. There
isn't much you can do about that, but choose a good cf card or usb stick.
Henry
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