Tuesday, February 23, 2010

Data Transfer in the Classroom

One interesting issue that has arisen, which was never an issue in a traditional classroom, is the issue of data transfer. As educators shift more and more towards a true 1:1 eLearning model, there will be an ever increasing need to transfer large amounts of data to each and every student. We're not just talking sending e-mails with .docs or .pdfs, or the odd You Tube .flv. We're talking bandwidth hogging HD videos, lengthy audio files, and picture libraries used for creating presentations. Even 100 MB of data, which is a trivial amount for an individual, poses significant logistical problems for the educator.

Do you transfer via USB key? That's slow and cumbersome, and unless you buy multiple keys, creates a significant bottleneck.

Do you burn the data onto DVDs? If it is a one off activity, this method is time consuming and expensive. To make it worthwhile, you would need to burn a term or a semester worth of material onto disks to give your students. But the amount of data you might use over that length of time could easily outstrip the capacity of a DVD, requiring you to burn two, or even three per student. Again, cumbersome and expensive.

Do you upload it and have students download the file? That bypasses the one-at-a-time issue faced by USB keys, but then you and your students are dependent on the vagaries of network performance. Is the network busy that day? At what rate can that file be downloaded from where you are hosting it. Do you have to pay to have the file hosted online? Are there bandwidth limits on your account? Throw in the odd 1GB file, and over the course of a month, you could be facing a large bill.

What about the Public Folder system? Macbooks come equipped with Public Folders which your students can access at any time over the network. In theory this system is perfect for the classroom. The problem is that only 10 students can connect to your Public Folder at one time, and if any forget to properly disconnect, others will be blocked out. In addition, even a file as small as 100 MB will suddenly create a classroom management situation, as during busy network periods, the average download time could top 20 to 30 minutes. What do the students do while they are downloading? How do you keep track of who has fully downloaded the file, and who's downloads were interrupted?

Personally, I prefer using an adapted Public Folder method, where I go to one students at each table, directly connect my Macbook to theirs with a regular ethernet cable, and transfer the data. With the direct connection, transfer speeds are blazing fast, and a 100 MB file takes a few seconds to transfer. To over come the bottleneck issue, I have my students in groups of three, and I employ the Give and Get system. After I "Give" the file to one student, the other two direct connect to the first, and they "Get" the file from them. In practice, when done right, I have found that you can transfer 500 MB to 1 GB of data to each student in your classroom in between 5 to 7 minutes.

It's not a perfect system, and requires both technical knowledge, and specific tools (6+ small ethernet cables for student use), but I have found it to be the most efficient system to date.

Each method brings certain upsides and downsides. Which method works best for you?

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