README.md in sysvmq-0.2.0 vs README.md in sysvmq-0.2.1

@@ -16,11 +16,11 @@
 
 Add `sysvm` to your Gemfile.
 
 `gem 'sysvmq'`
 
-Currently known to work on Linux and OS X for MRI >= 2.0.
+Currently known to work on Linux and OS X for MRI >= 1.9
 
 ## Usage
 
 ```ruby
 # Create a message queue with a 1024 byte buffer.
@@ -37,9 +37,32 @@
 
 ensure
 # Delete queue
 mq.destroy
 ```
+
+## Proc settings
+
+System V queues are limited by default to a maximum of 16 message queues, a maximum of 8KB per message, and a maximum of 16KB for the total size of all messages in a queue.
+
+To increase (or decrease) these limits, either run:
+
+```sh
+sysctl -w kernel.msgmni=32
+sysctl -w kernel.msgmax=1000000
+sysctl -w kernel.msgmnb=2000000
+```
+
+or write to /etc/sysctl.conf:
+
+```sh
+echo 'kernel.msgmni=32' >> /etc/sysctl.conf # maximum number of message queues
+echo 'kernel.msgmax=1000000' >> /etc/sysctl.conf # maximum number of bytes per message
+echo 'kernel.msgmnb=2000000' >> /etc/sysctl.conf # maximum total size of all messages in a queue
+sysctl -p
+```
+
+See http://man7.org/linux/man-pages/man5/proc.5.html for more information.
 
 ## Todo
 
 * Explain messages types
 * Add named params for flags (e.g. `mq.receive(:front, blocking: false)`)