diff --git a/412/midterm.md b/412/midterm.md
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+# Midterm Sample Questions
+
+Difference between NAS and SAN?
+
+Subnet: 
+
+* What kind of class is the given IP?
+
+* What is the subnet mask, network address, etc?
+
+* Subnet addresses?
+
+`Host & subnet mask(classless)`
+
+BTW: this is the analog of the network address(classful addressing). When we talk about network addresses we are implying a classful network.
+
+* Subnet bits
+
+i.e. 21 => 8+8+5+0 <= `5` is the odd one out so we have _5 subnet bits_
+
+* VLSM - Variable Length Subnet Mask
+
+
+Suppose we want to assign addresses to the following networks with x many hosts.
+A:600; B:1000; C:200
+
+`150.180.0.0/16`
+`150.181.0.0/16`
+
+Start with the largest network B : requires 1000 hosts.
+
+Hosts part requires 10 bits so we have an IP/22.
+
+Network address then is (subnet address)150.180.0.0/22 - (broadcast address)150.180.3.231/22.
+**NOTE:** we don't go up to to 255 on the end because: 
+
+A. We only need 1000 hosts
+B. We effectively "reuse" the 150.180 prefix to fit the next network; basically we use a "host" as a network.
+
+
diff --git a/412/monitoring.md b/412/monitoring.md
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+# Service Monitoring
+
+Several types of monitoring: 
+
+## Building Monitoring System
+
+If your monitoring a lot of _stuff_ know that you will could have lots of stuff going across the network(in some cases).
+Know that we have to _get data, store data, and ultimately view data_.
+
+## Historically
+
+SNMP: Usually you will get back a ton of data 
diff --git a/412/pass.md b/412/pass.md
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+# OpenFiler
+
+> both on the browser and the regular user account
+openfiler
+openfiler