Time Tracking Tools

Have you ever asked yourself how much time during the day in the office do you spend looking at funny youtube videos, reading emails, taking coffee or doing some boring administrative task that keeps you from getting your work finished? I’ve actually been asking myself that for what it feels my entire life. I always tought that a well organized and productive 3 hours could be more valuable than a whole day of distractions. I always wanted to measure that productivity in detail and see what things I’m spending my time on and how much. Now I finally can.

A few months ago I found out on Lifehacker about this software called RescueTime that tracks how you spend your time on a computer. It’s free and you run it in the background. It categrorizes your activities in Communication, Development Tools, Reference/Search etc. If you are using a browser it is smart enough to distinguish which sites are you accessing, so reading The Server Side and Failblog.org are considered two different activities.

 

One downside of RescueTime is that it posts your usage statistics to their servers, so if you don’t want anyone to see how much time you spent… watching porn in the office, you might choose to disable RescueTime for a couple of hours. On the other side, your usage statistics are accessible only by you, so your boss can’t detract from your salary every 5 mins you spent checking your private mail.

Another downside is that it doesn’t show you when exactly did you start working with a particular program and when were you AFK. So you can’t distinguish between a meeting and a lunch break.

Both of these problems are solved by ManicTime. Manic time works only locally and gives you information on what did you do at an exact moment of the day: 

 

 

The only downside of ManicTime is that it is too fine grained so you don’t get the quick overview that you can get in RescueTime. Currently I’m using both of them until I decide which one is better or one of them implements the functionalities of the other.

Active and Passive Replication in Distributed Systems

In the distributed systems research area replication is mainly used to provide fault tolerance. The entity being replicated is a process. Two replication strategies have been used in distributed systems: Active and Passive replication.

In active replication each client request is processed by all the servers. Active Replication was first introduced by Leslie Lamport under the name state machine replication. This requires that the process hosted by the servers is deterministic. Deterministic means that, given the same initial state and a request sequence, all processes will produce the same response sequence and end up in the same final state. In order to make all the servers receive the same sequence of operations, an atomic broadcast protocol must be used. An atomic broadcast protocol guarantees that either all the servers receive a message or none, plus that they all receive messages in the same order. The big disadvantage for active replication is that in practice most of the real world servers are non‐deterministic. Still active replication is the preferable choice when dealing with real time systems that require quick response even under the presence of faults or with systems that must handle byzantine faults.  

In passive replication there is only one server (called primary) that processes client requests. After processing a request, the primary server updates the state on the other (backup) servers and sends back the response to the client. If the primary server fails, one of the backup servers takes its place. Passive replication may be used even for non‐deterministic processes. The disadvantage of passive replication compared to active is that in case of failure the response is delayed.