The thing with looking back on the year

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I started this blog in August 2015, not quite a calendar year ago, but as the school year has now finished, it seems right to look back and see how far it has come.

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By a long way, the most popular posts have been about the Cambridge Nationals R001 exam – the first post for the summer exam dominating, but others also getting quite a lot of hits – of my year’s stats, the top 6 are all linked to the R001 exam. It seems there wasn’t a huge amount of other people putting things out there and we’ll see how successful the kids have been in applying the learning to the paper.

There’s a big question mark for me over how much I’ll be putting in to Cambridge Nationals this coming year – as the course is being ‘retired’, I don’t see us putting more than a tiny handful of resits through. I’m sure I can post a few summaries, but other courses will be taking over in our curriculum model and on this site.

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For me (and many others, it seems), this has been the Linux A452 Controlled Assessment. The DEC Levinux VM has led to a few enquiries from other teachers across the country, and several more have been asking after the resources I’ve used in-house to support my team in leading the CA with students. As this document gives partial answers, I’m not publishing it publicly online so that students can’t download it – email me if you’re after it.

As to next year, we’re probably not going to use the new Linux CA with our new GCSE groups, so I don’t plan to update Levinux to work specifically with that scenario. However, the ‘old’ one is current to submit in summer 2016, so I will continue to develop Levinux to make sure we can give our students the best resources.

One more thing

Most of the Computing teachers I know are using Python, so I’d like to highlight one resource that I’ve found helpful for completing programming projects, especially controlled assessment ones – the “cheat sheet“. The idea is to remind students of the skills they have practised in previous lessons so that they can concentrate on getting the logic right and support with debugging. It’s one that needs embedding – printing out and using across a series of lessons, modelling and demonstrating how it can be used well. I’m sure I’ll keep tweaking and improving the cheat sheet to match the tasks we’re doing.

This summer I’ll probably keep fairly quiet on the blog, let myself recharge for the new year, but I will post at least one more time with some ideas of what I’ll be planning for the coming year.  Have a relaxing break, but it’s worth taking some time to look back at your year to see where your successes have been and what challenges you have had to work on.

A452 Linux and Security

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I was chatting earlier on hangouts with a colleague in Bristol who has some challenges with the Linux Controlled Assessment – particularly concerns from the Network Technicians at his school. They have been very worried about the implications of allowing students to use a Linux computer – or worse a VirtualBox install which could potentially allow some really aggressive hacking vectors on the network.

I’d say there are tonnes of positives about using VirtualBox and a full VM for each student – or even using a LiveUSB approach, but also some issues that at least in our use scenario at my school are overcome with Levinux. You can also see my earlier thoughts on issues with Raspberry Pi‘s as a solution

In a later post coming up I’ll detail some of the issues we’ve had with Levinux and what I’m planning to do about them in future releases. I also intend to review the new CA tasks and give my very general thoughts (no spoilers!) on them; I have them in my queue to look at very soon! If you’ve not seen them, look on OCR Interchange – you’ll need a login

Live USB problems

I would personally (security aside) prefer the live USB route – though with the caveat that obviously some time would be lost each lesson re-booting the computer and an OS takes longer to load from a USB stick than a hard drive. Factor in losing 5+ minutes more than you would logging in to your network.

A full distro installed as a live USB is a really good solution for introducing what it’s like to ‘live’ in Linux full time – something that it proves is fully possible (right now I’m writing this on the Ubuntu PC that has been my main computer in various incarnations for over 10 years). However, the only place to save files is on that USB drive. Good luck getting them off without getting the internet involved (you’ll definitely need the internet so that the students can research) – maybe email to themselves or upload to the VLE? Not ideally secure for Controlled Assessment work? We’ve also had issues with USB drives going missing – ‘forgotten’ in a machine, put in a pocket, they could even be stolen. If that’s the whole CA work then it’s a really big deal.

Many Network Managers will get chills at the though of allowing anyone to boot a machine from USB – it’s a big security hole that could allow students full control over hard drives (wipe all installed software, install viruses with admin permissions…) and as it’s a dead certainty that they’ll need network connections, another issue there.

VirtualBox problems

Virtual box has many of the security issues of a USB drive, plus the potential for performance issues. A colleague who has recently joined another local school has complained of slow performance of VirtualBox machines when trying to run fairly simple software (like IDLE) on powerful brand new machines. And of course that is after logging in to Windows, finding the software and booting the VM.

VirtualBox machines also take a lot of storage – at least a few GB per student. That very quickly adds up when you consider a class or two of 25+, then all the backup space needed… Again, your Network Manager is getting squirmy.

But VirtualBox doesn’t only allow the distro you choose to install – maybe Ubuntu or something common. There are lots of hacking focussed VMs you can download with little more than a google search and Youtube videos on how you can use them to hack. Just as there’s no limit to what can be booted from a USB drive, there are no limits to what a VM in VirtualBox can do on the network, though there will be less ability to damage the local hard drive.

VirtualBox installs a few different drivers on the machine, too – low level access to the Operating System so it can do clever things like bridge the network connection and appear on the network to other computers. This is handy if you’re trying to set up a virtual server as a technician, or if you’re trying to redirect traffic to your VM (because you’re a hacking script-kiddie), but not necessary for the CA tasks.

Levinux works for us

I’m not trying to preach on this one, but if you have Techs that are totally dead-set against the other options, some of these arguments might work.

Levinux is light-weight in footprint – the zip download is just 26MB and expands to 36MB. The beauty of this is that it includes everything it needs to run, including QEMU (the software used by Google to help develop Android apps on the desktop). It can be run as a ‘portable program’ from a USB stick or from a local store on the hard drive or a network share. The implications of ~40MB per student versus say 2GB per student are quite clear.

Levinux is the only thing that Levinux can run – you’d need a lot of skills (well, a lot more than me) to use it to run a different, malicious distro. You’ll also find nothing that will help you hack a Windows network if you search for Levinux on Youtube! I’m not saying you couldn’t do it with 20 hours on your hands and a network connection, but there are a very small number of students who would be both capable enough, determined enough and able to ignore the CA task for long enough to do it!

Levinux, because it runs as a VM in Windows (or on Mac and Linux) allows you to use your normal set of software to research and write up – no new browser to get used to, your version of Office, your network folders, exactly as you do in every other lesson. The only learning curve is in the content of the questions and tasks, not in how to find out and write up. Simple printscreens into Word – everyone is used to that!

Levinux is quick – super responsive and boots from USB in less than 90 seconds – less time than it takes me to register my class! Boot from network is marginally slower, but much quicker than an Ubuntu Live CD or even a Raspberry Pi. QEMU is light-weight and as there’s almost nothing to load, Levinux takes up very little RAM as well as disk space.

If you’re interested in the training I’ve given to staff at my school, send me an email so you can see the suggested solutions using Levinux to all the problems of the 2014-16 Linux problems. Obviously this is not to be shared with students, so I can’t post it here!

Resource Review: Shell Handbook Linux Magazine Special

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I’ve use so many different resources and some of them are definitely worth recommending to other teachers – you’re busy and only want to look at the best! This series will bring together some of the best resources that I’ve found and let you know what makes them so compelling.

First up is one for the A452 Linux Practical Investigation for OCR GCSE Computing. Although I didn’t experience it this way as I’ve had so many years experience of using Linux and the shell, I know that for others in my team it was a really daunting thing to start on this project. The Linux Shell Handbook has really helped with that initial fear by putting into one place pretty much all that is needed to have a confident go at explaining completely new concepts.

This resource wasn’t designed for teaching, it’s a general industry wide tool that was created by Linux Magazine as a special issue. It doesn’t deliberately cover CA content and in fact covers a lot more ground than is needed for the project. What it does do is create a single go-to ‘text book’ style resource with credibility but also approachability.

I’ve shared the resource with staff and students at my school and it’s definitely one of the preferred things to go to when there’s a new task to look at. I have two copies on paper in my classroom that are always picked up to use by different students each lesson. I think that is the measure of a good resource – that the kids themselves use it and pass it on to each other.

You can download the Linux Shell Handbook for $15.99 (that’s USD, paid via Paypal, which came to £10.34 when I bought it about a month ago). I never looked too closely at buying it in ‘dead tree’ format as I printed the PDF out to use in my lessons. I’ve also split it up into chapters that the students can access as a shared resource so they download only the section they need for the task they’re on.

Highly Recommended – I only wish there were some sections on the oddities that different distros bring into the mix – some of the commands are distro-specific and as we’re using DEC Levinux which is based on TinyCore, there are parts of the CA that cannot be completed with the handbook – though this is a good opportunity for a wider range of resources to be used.

The thing with the updated DEC Levinux

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We’re now moving ahead with using Levinux in school – to be quite honest with some fear! Anyway, pre-release testing caught a few bugs in the system that you might want to see removed. DEC-Levinux now includes a working text editor, UK keyboard layout and some different files in the home directory.

The version I’m using in school has a copy of the CA task in the folders, I’ve obviously had to remove that to publish online, but if you dig far enough you’ll find references to it.

I’ve also created a working document to support my colleagues – not for kids at all. I’ve called it a ‘Teacher’s Linux Primer’ but really it’s more like a working set of solutions to the problems (apart from the last two tasks) so they can plan and support the groups with a feeling of knowing a solution. I’ll be publishing it with the next email update in the next week or so and possibly on TES. If you feel you need a draft copy more urgently, let me know and I’ll send you a copy – but I’ll not be putting it directly on the site as students may access it and it might be seen as a solution to the CA task.

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Download DEC Levinux (~25MB)

 

The thing with a custom Linux Distro

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My last post was about not using Raspberry Pis but instead experimenting with another Linux distribution that would run in a QEMU window. I’ve spent half a very productive holiday-day going through all the different files necessary to customise and refine the distro that I chose, Levinux.

If you’re interested in understanding how Linux works I can recommend this as an activity – otherwise, why not have a look at the results and see how you could use this in school?

Download Levinux-DEC (~25Mb)

I have made only a few changes, some cosmetic and some technical. I’ve removed the option to install Pipulate, Mike Levin’s web/SEO package and added a very basic text editor called “nano” to use straight out of the box. I have set the keyboard to UK instead of US. I’ve also looked at how to put the proxy straight into the config – I can do it easily and would happily send you a custom zip file with your school’s proxy details hard-coded in. This version has the proxy settings commented out.

This Linux distro will allow you to do everything that the OCR A452 CA task on Linux requires you to. I’ll be producing a teacher sheet with instructions of the shortest route to each task over the next few weeks to use in training at my school as well as a list of ‘recommended searches’ to help find out more in an efficient way. These won’t be public downloads from the site – you’ll need to join the email list for that – but I will flag them up as they are created.

Things to think about and let me know:

  • Are you planning to use Raspberry Pi or this for Coursework or Controlled Assessment?
  • Are there any crucial packages (for you) that are missing from this Distro – what would make it better for you?

The thing with not using a Pi

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Buying 30 Raspberry Pis per class is a bit steep for our budget, so I had planned to run our A452 investigation into Linux using shared Pis, treating it a bit like a science experiment. We had thought that while the printscreens would be the same for both candidates, the write-up would be totally different, even if the process was the same for both in the pair. We had some feedback from OCR (reproduced below) that suggested this was not the best route to take, so I’ve been looking at some other alternatives.

The first (referred from CAS forums) is Levinux – this is a super stripped down version that literally runs after you unzip the ~20MB file. It gives only a command prompt and even then only the basic BASH commands, not even a text editor included. If I go this route, I’d re-package it for our students, strip out some of the Matrix references and install a few small programs by default – including a simple text editor like nano.

Setting the proxy is a little different from the Raspberry Pi as it comes with a read-only base system which stops the way I’m used to setting the proxy. Instead, type this at the command line:

export http_proxy=http://your.proxy:port

At first I thought I had to do this every time, which is not nice. Finally I figured out doing this:

echo export http_proxy:http:your.proxy:port >> .profile
filetool.sh -b

This last command makes sure that the system state is saved and not wiped if you close the window. Another way of making sure nothing like this is lost is to close the session with

sudo poweroff

instead of just hitting the X button on screen.

My main Linux experience has been in Ubuntu and before that Debian, so the TinyCore Linux base of Levinux is a little bit foreign. All the key parts of the CA task can be solved with TC/Levinux, including installing Tree and creating users and groups, though obviously for installing you’ll need to have an internet connection set up.

 

The other option is to use a more full VM – preferably a version of Ubuntu for me, but it could be any full Linux. The Tech team here are looking into it for me as an option – that might give a fuller Linux experience for the kids.

I think I still want to use the Raspberry Pis in my introduction lessons for this unit and perhaps next year we’d do the whole project using them, but for now a VM might be the best route.