diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index 6a14e85382..5d0f51315b 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -83,6 +83,8 @@ def _config():
         help='Search history for the LRF viewer')
     c.add_opt('scheduler_search_history', default=[],
         help='Search history for the recipe scheduler')
+    c.add_opt('worker_limit', default=6,
+            help=_('Maximum number of waiting worker processes'))
 
     return ConfigProxy(c)
 
diff --git a/src/calibre/gui2/dialogs/config/__init__.py b/src/calibre/gui2/dialogs/config/__init__.py
index 915219ee11..b419b3afd1 100644
--- a/src/calibre/gui2/dialogs/config/__init__.py
+++ b/src/calibre/gui2/dialogs/config/__init__.py
@@ -457,6 +457,7 @@ class ConfigDialog(QDialog, Ui_Dialog):
         self.connect(self.sync_news, SIGNAL('toggled(bool)'),
                 self.delete_news.setEnabled)
         self.setup_conversion_options()
+        self.opt_worker_limit.setValue(config['worker_limit'])
 
     def create_symlinks(self):
         from calibre.utils.osx_symlinks import create_symlinks
@@ -696,6 +697,12 @@ class ConfigDialog(QDialog, Ui_Dialog):
             return
         if not self.add_save.save_settings():
             return
+        wl = self.opt_worker_limit.value()
+        if wl%2 != 0:
+            wl += 1
+        config['worker_limit'] = wl
+
+
         config['use_roman_numerals_for_series_number'] = bool(self.roman_numerals.isChecked())
         config['new_version_notification'] = bool(self.new_version_notification.isChecked())
         prefs['network_timeout'] = int(self.timeout.value())
diff --git a/src/calibre/gui2/dialogs/config/config.ui b/src/calibre/gui2/dialogs/config/config.ui
index dc180edba7..0ceeb78686 100644
--- a/src/calibre/gui2/dialogs/config/config.ui
+++ b/src/calibre/gui2/dialogs/config/config.ui
@@ -682,50 +682,43 @@
         </layout>
        </widget>
        <widget class="QWidget" name="page_2">
-        <layout class="QHBoxLayout" name="horizontalLayout_9">
-         <item>
-          <spacer>
-           <property name="orientation">
-            <enum>Qt::Horizontal</enum>
+        <layout class="QGridLayout" name="gridLayout_3">
+         <item row="0" column="0">
+          <widget class="QLabel" name="label_5">
+           <property name="text">
+            <string>&amp;Maximum number of waiting worker processes (needs restart):</string>
            </property>
-           <property name="sizeHint" stdset="0">
-            <size>
-             <width>154</width>
-             <height>20</height>
-            </size>
+           <property name="buddy">
+            <cstring>opt_worker_limit</cstring>
            </property>
-          </spacer>
+          </widget>
          </item>
-         <item>
-          <layout class="QVBoxLayout" name="verticalLayout_12">
-           <item>
-            <widget class="QPushButton" name="compact_button">
-             <property name="text">
-              <string>&amp;Check database integrity</string>
-             </property>
-            </widget>
-           </item>
-           <item>
-            <widget class="QPushButton" name="button_osx_symlinks">
-             <property name="text">
-              <string>&amp;Install command line tools</string>
-             </property>
-            </widget>
-           </item>
-          </layout>
+         <item row="0" column="1">
+          <widget class="QSpinBox" name="opt_worker_limit">
+           <property name="minimum">
+            <number>2</number>
+           </property>
+           <property name="maximum">
+            <number>10000</number>
+           </property>
+           <property name="singleStep">
+            <number>2</number>
+           </property>
+          </widget>
          </item>
-         <item>
-          <spacer>
-           <property name="orientation">
-            <enum>Qt::Horizontal</enum>
+         <item row="1" column="0" colspan="2">
+          <widget class="QPushButton" name="compact_button">
+           <property name="text">
+            <string>&amp;Check database integrity</string>
            </property>
-           <property name="sizeHint" stdset="0">
-            <size>
-             <width>153</width>
-             <height>20</height>
-            </size>
+          </widget>
+         </item>
+         <item row="2" column="0" colspan="2">
+          <widget class="QPushButton" name="button_osx_symlinks">
+           <property name="text">
+            <string>&amp;Install command line tools</string>
            </property>
-          </spacer>
+          </widget>
          </item>
         </layout>
        </widget>
diff --git a/src/calibre/gui2/jobs.py b/src/calibre/gui2/jobs.py
index e4406447d1..2cd25e1b4e 100644
--- a/src/calibre/gui2/jobs.py
+++ b/src/calibre/gui2/jobs.py
@@ -15,7 +15,7 @@ from PyQt4.Qt import QAbstractTableModel, QVariant, QModelIndex, Qt, \
 
 from calibre.utils.ipc.server import Server
 from calibre.utils.ipc.job import ParallelJob
-from calibre.gui2 import Dispatcher, error_dialog, NONE
+from calibre.gui2 import Dispatcher, error_dialog, NONE, config
 from calibre.gui2.device import DeviceJob
 from calibre.gui2.dialogs.jobs_ui import Ui_JobsDialog
 from calibre import __appname__
@@ -31,7 +31,7 @@ class JobManager(QAbstractTableModel):
 
         self.jobs          = []
         self.add_job       = Dispatcher(self._add_job)
-        self.server        = Server()
+        self.server        = Server(limit=int(config['worker_limit']/2.0))
         self.changed_queue = Queue()
 
         self.timer         = QTimer(self)
diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index e87e6a4a04..2c43906778 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -530,7 +530,7 @@ class Main(MainWindow, Ui_MainWindow, DeviceGUI):
                 self._sync_menu.trigger_default)
 
     def add_spare_server(self, *args):
-        self.spare_servers.append(Server())
+        self.spare_servers.append(Server(limit=int(config['worker_limit']/2.0)))
 
     @property
     def spare_server(self):
diff --git a/src/calibre/translations/calibre.pot b/src/calibre/translations/calibre.pot
index c405fd1042..85a30131d5 100644
--- a/src/calibre/translations/calibre.pot
+++ b/src/calibre/translations/calibre.pot
@@ -5,8 +5,8 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: calibre 0.6.11\n"
-"POT-Creation-Date: 2009-09-10 20:58+MDT\n"
-"PO-Revision-Date: 2009-09-10 20:58+MDT\n"
+"POT-Creation-Date: 2009-09-10 21:29+MDT\n"
+"PO-Revision-Date: 2009-09-10 21:29+MDT\n"
 "Last-Translator: Automatically generated\n"
 "Language-Team: LANGUAGE\n"
 "MIME-Version: 1.0\n"
@@ -94,8 +94,8 @@ msgstr ""
 #: /home/kovid/work/calibre/src/calibre/ebooks/pdf/writer.py:29
 #: /home/kovid/work/calibre/src/calibre/ebooks/rtf/input.py:139
 #: /home/kovid/work/calibre/src/calibre/ebooks/rtf/input.py:141
-#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:261
-#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:268
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:263
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:270
 #: /home/kovid/work/calibre/src/calibre/gui2/add.py:111
 #: /home/kovid/work/calibre/src/calibre/gui2/add.py:118
 #: /home/kovid/work/calibre/src/calibre/gui2/convert/__init__.py:21
@@ -1848,7 +1848,7 @@ msgid "Add a tab at the beginning of each paragraph."
 msgstr ""
 
 #: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:27
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:505
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:508
 msgid "Frequently used directories"
 msgstr ""
 
@@ -1936,16 +1936,20 @@ msgstr ""
 msgid "Default action to perform when send to device button is clicked"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:123
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:87
+msgid "Maximum number of waiting worker processes"
+msgstr ""
+
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:125
 #: /home/kovid/work/calibre/src/calibre/gui2/wizard/__init__.py:397
 msgid "Copied"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:152
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:154
 msgid "Copy"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:152
+#: /home/kovid/work/calibre/src/calibre/gui2/__init__.py:154
 msgid "Copy to Clipboard"
 msgstr ""
 
@@ -2143,14 +2147,14 @@ msgstr ""
 #: /home/kovid/work/calibre/src/calibre/gui2/convert/xexp_edit_ui.py:44
 #: /home/kovid/work/calibre/src/calibre/gui2/device_drivers/configwidget_ui.py:61
 #: /home/kovid/work/calibre/src/calibre/gui2/device_drivers/configwidget_ui.py:62
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:491
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:503
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:504
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:494
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:506
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:507
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:509
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:525
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:526
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:556
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:510
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:512
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:528
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:529
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:560
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/metadata_single_ui.py:343
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/metadata_single_ui.py:348
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/metadata_single_ui.py:362
@@ -3179,126 +3183,126 @@ msgstr ""
 msgid "new email address"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:465
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:798
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:466
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:805
 #: /home/kovid/work/calibre/src/calibre/gui2/main.py:140
 #: /home/kovid/work/calibre/src/calibre/gui2/main.py:1004
 #: /home/kovid/work/calibre/src/calibre/utils/ipc/job.py:52
 msgid "Error"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:466
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:467
 msgid "Failed to install command line tools."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:469
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:470
 msgid "Command line tools installed"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:470
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:471
 msgid "Command line tools installed in"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:471
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:472
 msgid "If you move calibre.app, you have to re-install the command line tools."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:522
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:523
 msgid "No valid plugin path"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:523
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:524
 msgid "%s is not a valid plugin path"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:526
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:527
 msgid "Choose plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:538
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:539
 msgid "Plugin cannot be disabled"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:539
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:540
 msgid "The plugin: %s cannot be disabled"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:548
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:549
 msgid "Plugin not customizable"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:549
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:550
 msgid "Plugin: %s does not need customization"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:573
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:574
 msgid "Customize %s"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:583
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:584
 msgid "Cannot remove builtin plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:584
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:585
 msgid " cannot be removed. It is a builtin plugin. Try disabling it instead."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:617
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:618
 msgid "Error log:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:624
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:625
 msgid "Access log:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:649
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:650
 #: /home/kovid/work/calibre/src/calibre/gui2/main.py:573
 msgid "Failed to start content server"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:673
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:674
 #: /home/kovid/work/calibre/src/calibre/gui2/wizard/__init__.py:470
 msgid "Select location for books"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:690
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:691
 msgid "Invalid size"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:691
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:692
 msgid "The size %s is invalid. must be of the form widthxheight"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:735
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:740
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:742
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:747
 msgid "Invalid database location"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:736
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:743
 msgid "Invalid database location "
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:737
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:744
 msgid "<br>Must be a directory."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:741
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:748
 msgid "Invalid database location.<br>Cannot write to "
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:779
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:786
 msgid "Checking database integrity"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:799
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:806
 msgid "Failed to check database integrity"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:804
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:811
 msgid "Some inconsistencies found"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:805
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/__init__.py:812
 msgid "The following books had formats listed in the database that are not actually available. The entries for the formats have been removed. You should check them manually. This can happen if you manipulate the files in the library folder directly."
 msgstr ""
 
@@ -3382,256 +3386,260 @@ msgstr ""
 msgid "&Saving books"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:488
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:491
 #: /home/kovid/work/calibre/src/calibre/gui2/main_ui.py:367
 #: /home/kovid/work/calibre/src/calibre/gui2/viewer/main_ui.py:173
 msgid "Preferences"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:489
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:492
 msgid "&Location of ebooks (The ebooks are stored in folders sorted by author and metadata is stored in the file metadata.db)"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:490
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:493
 msgid "Browse for the new database location"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:492
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:495
 msgid "Show notification when &new version is available"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:493
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:496
 msgid "Default network &timeout:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:494
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:497
 msgid "Set the default timeout for network fetches (i.e. anytime we go out to the internet to get information)"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:495
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:498
 msgid " seconds"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:496
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:499
 msgid "Choose &language (requires restart):"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:497
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:500
 msgid "Normal"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:498
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:501
 msgid "High"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:499
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:502
 msgid "Low"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:500
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:503
 msgid "Job &priority:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:501
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:504
 msgid "Preferred &output format:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:502
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:505
 msgid "Preferred &input format order:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:506
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:509
 msgid "Add a directory to the frequently used directories list"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:508
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:511
 msgid "Remove a directory from the frequently used directories list"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:510
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:513
 msgid "Use &Roman numerals for series number"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:511
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:514
 msgid "Enable system &tray icon (needs restart)"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:512
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:515
 msgid "Show &notifications in system tray"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:513
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:516
 msgid "Show cover &browser in a separate window (needs restart)"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:514
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:517
 msgid "Search as you type"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:515
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:518
 msgid "Automatically send downloaded &news to ebook reader"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:516
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:519
 msgid "&Delete news from library when it is automatically sent to reader"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:517
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:520
 msgid "&Number of covers to show in browse mode (needs restart):"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:518
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:521
 msgid "Toolbar"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:519
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:522
 msgid "Large"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:520
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:523
 msgid "Medium"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:521
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:524
 msgid "Small"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:522
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:525
 msgid "&Button size in toolbar"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:523
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:526
 msgid "Show &text in toolbar buttons"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:524
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:527
 msgid "Select visible &columns in library view"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:527
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:530
 msgid "Use internal &viewer for:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:528
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:531
 msgid "Add an email address to which to send books"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:529
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:532
 msgid "&Add email"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:530
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:533
 msgid "Make &default"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:531
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:534
 msgid "&Remove email"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:532
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:535
 msgid "calibre can send your books to you (or your reader) by email"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:533
-msgid "&Check database integrity"
-msgstr ""
-
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:534
-msgid "&Install command line tools"
-msgstr ""
-
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:535
-msgid "calibre contains a network server that allows you to access your book collection using a browser from anywhere in the world. Any changes to the settings will only take effect after a server restart."
-msgstr ""
-
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:536
-msgid "Server &port:"
+msgid "&Maximum number of waiting worker processes (needs restart):"
 msgstr ""
 
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:537
+msgid "&Check database integrity"
+msgstr ""
+
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:538
+msgid "&Install command line tools"
+msgstr ""
+
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:539
+msgid "calibre contains a network server that allows you to access your book collection using a browser from anywhere in the world. Any changes to the settings will only take effect after a server restart."
+msgstr ""
+
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:540
+msgid "Server &port:"
+msgstr ""
+
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:541
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/password_ui.py:58
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/scheduler_ui.py:178
 #: /home/kovid/work/calibre/src/calibre/gui2/wizard/send_email_ui.py:117
 msgid "&Username:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:538
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:542
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/password_ui.py:59
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/scheduler_ui.py:179
 #: /home/kovid/work/calibre/src/calibre/gui2/wizard/send_email_ui.py:119
 msgid "&Password:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:539
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:543
 msgid "If you leave the password blank, anyone will be able to access your book collection using the web interface."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:540
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:544
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/password_ui.py:60
 #: /home/kovid/work/calibre/src/calibre/gui2/dialogs/scheduler_ui.py:180
 msgid "&Show password"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:541
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:545
 msgid "The maximum size (widthxheight) for displayed covers. Larger covers are resized. "
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:542
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:546
 msgid "Max. &cover size:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:543
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:547
 msgid "&Start Server"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:544
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:548
 msgid "St&op Server"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:545
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:549
 msgid "&Test Server"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:546
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:550
 msgid "Run server &automatically on startup"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:547
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:551
 msgid "View &server logs"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:548
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:552
 #: /home/kovid/work/calibre/src/calibre/gui2/wizard/stanza_ui.py:46
 msgid ""
 "<p>Remember to leave calibre running as the server only runs as long as calibre is running.\n"
 "<p>Stanza should see your calibre collection automatically. If not, try adding the URL http://myhostname:8080 as a new catalog in the Stanza reader on your iPhone. Here myhostname should be the fully qualified hostname or the IP address of the computer calibre is running on."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:550
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:554
 msgid "Here you can customize the behavior of Calibre by controlling what plugins it uses."
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:551
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:555
 msgid "Enable/&Disable plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:552
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:556
 msgid "&Customize plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:553
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:557
 msgid "&Remove plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:554
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:558
 msgid "Add new plugin"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:555
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:559
 msgid "Plugin &file:"
 msgstr ""
 
-#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:557
+#: /home/kovid/work/calibre/src/calibre/gui2/dialogs/config/config_ui.py:561
 msgid "&Add"
 msgstr ""
 
diff --git a/src/calibre/utils/ipc/server.py b/src/calibre/utils/ipc/server.py
index f8bed4ce2d..c00f2479c9 100644
--- a/src/calibre/utils/ipc/server.py
+++ b/src/calibre/utils/ipc/server.py
@@ -6,7 +6,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, cPickle, time, tempfile
+import sys, os, cPickle, time, tempfile
 from math import ceil
 from threading import Thread, RLock
 from Queue import Queue, Empty
@@ -83,14 +83,16 @@ class CriticalError(Exception):
 
 class Server(Thread):
 
-    def __init__(self, notify_on_job_done=lambda x: x, pool_size=None):
+    def __init__(self, notify_on_job_done=lambda x: x, pool_size=None,
+            limit=sys.maxint):
         Thread.__init__(self)
         self.daemon = True
         global _counter
         self.id = _counter+1
         _counter += 1
 
-        self.pool_size = cpu_count() if pool_size is None else pool_size
+        limit = min(limit, cpu_count())
+        self.pool_size = limit if pool_size is None else pool_size
         self.notify_on_job_done = notify_on_job_done
         self.auth_key = os.urandom(32)
         self.address = arbitrary_address('AF_PIPE' if iswindows else 'AF_UNIX')