Hi Jan,
I understand that search ROM is costly, but:
1. on reading uncached, owfs should, like you say, update its view on the
bus. Nevertheless, this does not seem to happen:
# ls -la /mnt/owfs/uncached/1F.F96B08000000/aux/30.4CF9B8120000/
total 0
drwxrwxrwx 1 root root 8 Apr 16 17:42 .
drwxr-xr-x 1 root root 8 Apr 16 09:34 ..
--w--w--w- 1 root root 1 Apr 16 17:42 PIO
drwxrwxrwx 1 root root 8 Apr 16 17:42 WS603
...
# ls -la /mnt/owfs/1F.F96B08000000/aux/30.4CF9B8120000/
total 0
drwxrwxrwx 1 root root 8 Apr 16 17:42 .
drwxr-xr-x 1 root root 8 Apr 16 09:34 ..
--w--w--w- 1 root root 1 Apr 16 17:42 PIO
drwxrwxrwx 1 root root 8 Apr 16 17:42 WS603
...
Note that both the uncached and the normal read still shows the removed
device.
2. Even the cache has a limited lifetime, as shown here:
# owfs --help=cache
1-WIRE access programs by Paul H Alfille and others.
Cache and Timing Help
Caching (temporary storage of data in program memory for efficiency)
--uncached Implicit /uncached in all requests
--cached Explicit /uncached needed. (Default action)
--cache_size n Size in bytes of max cache memory. 0 for no limit.
Cache timing [default] (in seconds)
--timeout_volatile [ 15] Expiration time for changing data (e.g.
temperature)
--timeout_stable [300] Expiration time for stable data (e.g.
temperature limit)
--timeout_directory [ 60] Expiration of directory lists
--timeout_presence [120] Expiration of known 1-wire device location
Like I said before, the bus (bus master? owfs? fuse?) has been in this
state for 3+ days, way past any of the timers shown above (the applicable
one in this case being --timeout_presence, I suppose, the expiration after
which the device is removed from the tree). All other devices on bus are
duly removed after roughly this time (max 2 minutes), with the exception of
this DS2762, but this one seems to persist even across reboots, which no
cache should survive, I believe.
br,
Ors
On Wed, Apr 16, 2014 at 12:25 PM, Jan Kandziora <j...@gmx.de> wrote:
> Am 16.04.2014 11:12, schrieb Ors Tiszay:
> > Nor should the file system one the device is disconnected, but someone
> will
> > correct me on this if wrong.
> >
> "Search ROM" is a costly operation on most host adapters (with the
> noteable execption of the DS9490, which handles it semi-automatically)
> so owfs doesn't do that automatically. You have to read /uncached to
> have owfs update it's view on the bus. That's the reason why there is a
> node "present" in each device directory. You can check whether a device
> is still there without having to "Search ROM" by reading that node (in
> "uncached" of course).
>
> Kind regards
>
> Jan
>
>
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