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document another bug in README

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1 parent 06e3ff1 commit 6854518d40684a354fb6f7a39c17579f832648a7 Ben Crowell committed Oct 8, 2011
Showing with 10 additions and 4 deletions.
  1. +8 −3 README
  2. +2 −1 vernier.rb
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11 README
@@ -28,9 +28,8 @@ GUI
The sample program in the file "photogate" collects data from a photogate, printing out the time for which
it is blocked. You can run it using the command "ruby photogate".
-The sample program in the file "force" will continuously read out as many force probes as are connected
-to the LabPro. All of the probes must be set to the 10 N scale. Bug: I have observed that this does not
-actually work properly with four force probes connected. I need to work more on this.
+The sample program in the file "force" will continuously read out a force probe, which
+must be set to the 10 N scale.
If these cause an error "Operation not permitted," then see below under Permissions.
@@ -57,3 +56,9 @@ Adding user accounts to the plugdev group does not seem to be sufficient.
See:
http://ubuntuforums.org/showthread.php?p=11314033
http://ubuntuforums.org/showpost.php?p=5565853&postcount=16
+
+BUGS
+
+The force probe program doesn't work properly with four force probes connected.
+
+Vernier.rb crashes when the LabPro is powered off.
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3 vernier.rb
@@ -237,7 +237,8 @@ def initialize(options={})
@is_open = true
@when_i_die["is_open"] = @is_open
ObjectSpace.undefine_finalizer(self); ObjectSpace.define_finalizer( self, proc {|id| LabPro.finalize(id,@when_i_die) })
- #----- If necessary, detach vstusb driver.
+ #----- If necessary, detach vstusb driver. This is needed on kernels 2.6.31-14 through about 2.6.32, in which the kernel would automatically
+ # claim the interface using this driver.
@interface = 0 # I just guessed the 0, but it does seem to be right. Changing it to 1 gives Errno::ENOENT elsewhere.
if File.exist?("/dev/vstusb0") then
# ...on Windows, the file won't exist, so this is harmless

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