diff --git a/Gemfile.lock b/Gemfile.lock
index f8a2757..ac5261e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,34 +1,35 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    diff-lcs (1.2.5)
-    docile (1.1.5)
-    json (2.0.2)
+    diff-lcs (1.5.1)
+    docile (1.4.1)
     memcached (1.8.0)
-    rake (11.2.2)
-    redcarpet (3.3.4)
-    rspec (3.5.0)
-      rspec-core (~> 3.5.0)
-      rspec-expectations (~> 3.5.0)
-      rspec-mocks (~> 3.5.0)
-    rspec-core (3.5.3)
-      rspec-support (~> 3.5.0)
-    rspec-expectations (3.5.0)
+    rake (13.2.1)
+    redcarpet (3.6.0)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.2)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.3)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.5.0)
-    rspec-mocks (3.5.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.2)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.5.0)
-    rspec-support (3.5.0)
-    simplecov (0.12.0)
-      docile (~> 1.1.0)
-      json (>= 1.8, < 3)
-      simplecov-html (~> 0.10.0)
-    simplecov-html (0.10.0)
-    yard (0.9.5)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.13.1)
+    simplecov_json_formatter (0.1.4)
+    yard (0.9.37)
 
 PLATFORMS
   ruby
+  x86_64-linux
 
 DEPENDENCIES
   memcached
@@ -39,4 +40,4 @@ DEPENDENCIES
   yard
 
 BUNDLED WITH
-   1.11.2
+   2.5.23
diff --git a/lib/diskcached.rb b/lib/diskcached.rb
index 9cd2867..f4f388e 100644
--- a/lib/diskcached.rb
+++ b/lib/diskcached.rb
@@ -1,7 +1,7 @@
 # @author Joshua P. Mervine <joshua@mervine.net>
 class Diskcached
   # version for gem
-  VERSION = '1.1.3'
+  VERSION = '1.1.4'
 
   # disk location for cache store
   attr_reader :store
@@ -45,16 +45,15 @@ def timeout=(t)
     @gc_time = t
   end
 
-  # return true if cache with 'key' is expired
+  # return true if cache with 'key' is expired or there is no cache entry
   def expired? key
-    return false if timeout.nil?
     mtime = read_cache_mtime(key)
-    return (mtime.nil? || mtime+timeout <= Time.now)
+    return mtime.nil? || (timeout && mtime+timeout <= Time.now)
   end
 
   # expire cache with 'key'
   def delete key
-    File.delete( cache_file(key) ) if File.exists?( cache_file(key) )
+    File.delete( cache_file(key) ) if File.exist?( cache_file(key) )
   end
 
   # expire (delete) all caches in #store directory
@@ -120,7 +119,7 @@ def set key, value
   #   or raises Diskcache::NotFound
   # - if 'key' is an Array returns only keys
   #   which exist and aren't expired, it raises
-  #   Diskcache::NotFound if none are available
+  #   Diskcached::NotFound if none are available
   def get key
     if key.is_a? Array
       ret = {}
@@ -149,7 +148,7 @@ def cache_file key
   private
   # creates the actual cache file
   def write_cache_file key, content
-    f = File.open( cache_file(key), "w+" )
+    f = File.open( cache_file(key), "wb+" )
     f.flock(File::LOCK_EX)
     f.write( content )
     f.close
@@ -158,7 +157,7 @@ def write_cache_file key, content
 
   # reads the actual cache file
   def read_cache_file key
-    f = File.open( cache_file(key), "r" )
+    f = File.open( cache_file(key), "rb" )
     f.flock(File::LOCK_SH)
     out = f.read
     f.close
@@ -168,7 +167,7 @@ def read_cache_file key
   # returns mtime of cache file or nil if
   # file doesn't exist
   def read_cache_mtime key
-    return nil unless File.exists?(cache_file(key))
+    return nil unless File.exist?(cache_file(key))
     File.mtime( cache_file(key) )
   end
 
@@ -177,7 +176,7 @@ def ensure_store_directory
     FileUtils.mkpath( store ) unless File.directory?( store )
   end
 
-  class NotFound < Exception
+  class NotFound < StandardError
   end
 
 end
diff --git a/spec/diskcached_spec.rb b/spec/diskcached_spec.rb
index 95a2546..0661e0d 100644
--- a/spec/diskcached_spec.rb
+++ b/spec/diskcached_spec.rb
@@ -38,7 +38,7 @@
       expect(@cache.set('test1', "test string")).to be_truthy
     end
     it "should create a file on disk" do
-      expect(File.exists?(File.join($cachedir, "test1.cache"))).to be_truthy
+      expect(File.exist?(File.join($cachedir, "test1.cache"))).to be_truthy
     end
   end
 
@@ -81,10 +81,10 @@
       expect(@cache.cache('test1') do
         "test string"
       end).to eq "test string"
-      expect(File.exists?(File.join($cachedir, "test1.cache"))).to be_truthy
+      expect(File.exist?(File.join($cachedir, "test1.cache"))).to be_truthy
     end
     it "should create a file on disk" do
-      expect(File.exists?(File.join($cachedir, "test1.cache"))).to be_truthy
+      expect(File.exist?(File.join($cachedir, "test1.cache"))).to be_truthy
     end
     it "should read cache before expiration" do
       expect(@cache.cache('test1')).to eq "test string"
@@ -116,6 +116,19 @@
       expect(@cache.expired?('test2')).to be_truthy
     end
   end
+  
+  describe "#expired?_timeout" do
+    before(:all) do
+      @cache = Diskcached.new($cachedir, nil)
+    end
+    it "should be true" do
+      expect(@cache.expired?('test2')).to be_falsey
+    end
+    it "should be false" do
+      @cache.cache('test2') { "cache test2" }
+      expect(@cache.expired?('test2')).to be_falsey
+    end
+  end
 
   describe "#delete" do
     before(:all) do
@@ -128,7 +141,7 @@
       expect(@cache.expired?('test3')).to be_truthy
     end
     it "should remove cache file" do
-      expect(File.exists?(File.join($cachedir, "test3.cache"))).to be_falsey
+      expect(File.exist?(File.join($cachedir, "test3.cache"))).to be_falsey
     end
   end
 
@@ -168,13 +181,13 @@
       expect(@cache.expired?('flush1')).to be_truthy
       @cache.instance_variable_set(:@gc_last, Time.now)
       expect { @cache.flush_expired }.to_not raise_error
-      expect(File.exists?(File.join($cachedir, "flush1.cache"))).to be_truthy
+      expect(File.exist?(File.join($cachedir, "flush1.cache"))).to be_truthy
     end
     it "should flush caches are are expired" do
       sleep 2
       expect { @cache.flush_expired }.to_not raise_error
       expect(@cache.expired?('flush1')).to be_truthy
-      expect(File.exists?(File.join($cachedir, "flush1.cache"))).not_to be_truthy
+      expect(File.exist?(File.join($cachedir, "flush1.cache"))).not_to be_truthy
     end
   end
 
@@ -193,7 +206,7 @@
       expect(@cache.expired?('flush1')).to be_truthy
       @cache.instance_variable_set(:@gc_last, Time.now)
       expect { @cache.flush_expired! }.to_not raise_error
-      expect(File.exists?(File.join($cachedir, "flush1.cache"))).to_not be_truthy
+      expect(File.exist?(File.join($cachedir, "flush1.cache"))).to_not be_truthy
     end
   end
 
@@ -217,9 +230,9 @@
       sleep 2
       expect { @cache.cache('test10') { "cache test10" } }.to_not raise_error
       sleep 1
-      expect(File.exists?(@cache.cache_file('test8'))).to be_falsey
-      expect(File.exists?(@cache.cache_file('test9'))).to be_falsey
-      expect(File.exists?(@cache.cache_file('test10'))).to be_truthy
+      expect(File.exist?(@cache.cache_file('test8'))).to be_falsey
+      expect(File.exist?(@cache.cache_file('test9'))).to be_falsey
+      expect(File.exist?(@cache.cache_file('test10'))).to be_truthy
     end
   end
 
@@ -234,9 +247,9 @@
       sleep 2
       expect { @cache.cache('test10') { "cache test10" } }.to_not raise_error
       sleep 1
-      expect(File.exists?(@cache.cache_file('test8'))).to be_truthy
-      expect(File.exists?(@cache.cache_file('test9'))).to be_truthy
-      expect(File.exists?(@cache.cache_file('test10'))).to be_truthy
+      expect(File.exist?(@cache.cache_file('test8'))).to be_truthy
+      expect(File.exist?(@cache.cache_file('test9'))).to be_truthy
+      expect(File.exist?(@cache.cache_file('test10'))).to be_truthy
     end
   end