I have never really been a true beta tester prior to getting involved in MinecraftEdu. I mean I purchased Minecraft while it was in beta, but never reported any bugs. So I might not have a lot of experience to call on but I can tell you working with the developers of MinecraftEdu is an absolutely amazing experience. I get access to what they call 'pre-release' versions to go on a bug hunt and test out new features and make sure everything is running smooth enough for a public release.
For the last 2 nights I have been chatting to the lead developer Aleksi about the lag happening in MinecraftEdu servers, on world start up and also there was a cry for help on the Minecraft Teachers Google Group about a map that was having huge lag issues in a particular area of the map. So Aleksi and I were both flying around the map on our respective servers suffering from a large amount of lag trying to work out the source. I was clearing edu specific blocks to see if that was the issue, as loading the same map in a vanilla Minecraft server caused no lag, so it was definitely specific to the edu version.
Anyway after about 4 hours of testing I went to bed, and since Aleksi is in Finland and it was day he kept working. I woke up this morning to the wonderful news that he had found the source of the problem and had fixed it, it was simply that the edu server was calling the 'sign' file almost constantly. So, with my very limited understanding, Aleksi made the server put the sign file into memory instead of pulling it off the disk, that has sped up the server markedly. The reason it was causing lag in this particular region of the map is because there were "seats" everywhere, which if you are a minecrafter you will know, have signs as the arms.
Now tonight we have been trying to work out where the lag is coming from when you start an edu server. Using the same settings vanilla Minecraft was generating a new world in around 15 seconds, while the same map was generating in 50 seconds if you did it in edu, this is different on every server of course, but those were the times on mine. After several hours of messing around, again nothing can be attributed to me, Aleksi has found the issue and has fixed it, so now vanilla and edu generate the world in the same amount of time. He is about to give me the new version to test out for myself and I am amazed at his coding prowess and bug squishing skills.
The reason I am writing this post is to acknowledge, again with my limited experience, the amount of work that the development team producing MinecraftEdu put into creating a stable, bug free build for public release. I don't think that I would have got the same response from the developers of Minecraft when it was in beta stage, perhaps because so many people were testing it. A massive hat tip to Aleksi for listening when we say "this isn't working" or "this doesn't do what it is supposed to" and actually spending so much of his time not only fixing and altering things based on our feedback, but also for chatting and explaining to me what he is doing while fixing issues.
I really appreciate it, and thought that I should let the MinecraftEdu community know that Aleksi (who I am currently calling the 'code king') does listen to feedback, acts on it and uses it to create a better product for you. So if you are having issues with MinecraftEdu let us know via the google group linked above, request membership if you have not already and join us in our discussions about using MinecraftEdu (or Minecraft) in schools.