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July 07, 2014

Phone number of a computer

The children have learnt to program with scratch at different speeds and as part of different groups. Some learnt it over the summer. Some children were in a different grade before being part of the multi-grade classroom (15 kids from 6th to 8th grade) and they have all used different machines. One of the issues that cropped up was that a child wanted to use only one machine since the child would have its work on that machine. I had used sftp and other such protocols, but was not sure how to set it up. Also my time beyond the classroom is limited and I am unable to be a sysad. I checked the minumum needed for a file transfer was to start listening to port 22 and this I did.

I thought the children would find it fun to think of communication across machines. I started with a analogy using cellphones. What if you called someone from another person's cellphone and then wanted to save it on ones own phone. The first solution was that one person can read out and the other can punch it in (I wonder if that is indeed the fastest!), within a second another kid suggested that you can SMS the number. Well, the village kids growing up in this connected world age find the cellphone quite intuitive (memo to andriod - you should not need to install an app to SMS phone numbers!)

We then started talking about what is needed to make this happen. We should know the phone number to SMS to, there should be a network and even one that suggested that there should be a battery in the phone. Since the kids brought up batteries we started talking about the SIM card and what functionality it could have. e.g. What happens if the SIM card from a phone is removed? What happens if the SIM card placed in another phone? Again, its amazing how much kids know about cellphones.

We then talked about how cellphones communicate to each other. The kids immediately brought up 'tower' and then how it goes to a satellite and comes back! Ok. Well what if two phones were close by, would they need to go out of their way? We then talked about networks that are connected to each other and at times when no physical network is available signals needing to take off.

I mentioned that the internet is one more network and pointed out that much more can be done other than going receiving data from the internet. We could also send information, including transferring files between machines. I proposed that it was like making a phone call. You needed to know the number of the person who you were calling, they would need to pick up, but then since these were machines talking not people there would be additional checks and balances.

I had installed Filezilla on one of the machines and tried to transfer to the pseudo server. This had worked the day before. I had, however, not had the time to install this on the other machines. The first step then get the children to go through the process of installing filezilla (minus root password). 

The next step was to figure out how to give filezilla the phone number of the computer. We did this and then entered additional data like the login and password (the information they need to log into machines).

The first try did not work and said that there was no response. I realized that having turned on the ports once the previous day was not enough and I turned it on again. 

Then was the issue of getting the passwd exactly right. This proved a little tough as it needed to be verbatim and the approximations children make to instructions of the teachers simply did not work and voila they were in.

The children seemed quite excited that they could transfer files between machines and one of them even looked up at the big monitor (connected to the pseudo server) expecting a visible reaction from the machine having transferred his file.

For closure of this experiment I went ahead and let each group of children who transferred files to present some of their work on the big screen to reward their work and prove to them that the files actually did get transferred.

Of course, we will move to a more permanent solution of mounting a drive on all the machines, but it was fun to enjoy the journey and not only the destination.

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