How are IT Techs going to be able to cope?

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by piglet » Mon Jun 11, 2012 1:44 pm
This is something which has been rattling round my brain for a while now, not thought through fully - but seems a bit of a problem.

If you suddenly introduce this in a 4 form entry secondary school to all pupils years 1-5 (8 to 12 in new money), you're looking at having to prepare 5*4*30=600 SD cards.

School PC's are unlikely to have SD card slots in them for pupils to write their own - and if they do they're probably locked down to stop nefarious activity.

Even at half that volume you're going to have a massive job for someone to initially prepare them - and to keep rewriting them when pupils trash them.

What will the best way be for schools to reliably replicate out large numbers of pi-ready SD cards?
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by SN » Mon Jun 11, 2012 1:51 pm
I posed this question back in March
The reality is that if you keep to 2Gb or 4Gb cards it is trivial (and quick) to 'reburn' them off a Windows PC with WIn32DiskImager - would still take an hour to prep 30 cards though
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by rurwin » Mon Jun 11, 2012 2:14 pm
That's what detentions are for. ;-)

I thought some people were trying to design a bulk-flashing device. What happened to that?
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by Joe Schmoe » Mon Jun 11, 2012 2:15 pm
I think the assumption is that the educational release will include (known good) SD card and (known good) power supply.

That's why they keep calling the current release "for developers".
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by rurwin » Mon Jun 11, 2012 2:21 pm
Yes it will. But kids will be kids, so there will be some wastage. Also a school may have its own prefered image.

Hmmm... Bulk flashing device.... ten RaspPis in a box with an ethernet hub and each one has a USB card reader. There's a USB HDD somewhere. Total cost: ($35 + $5) x 10 + $20 + $80 = $500 + taxes

Have a screen and keyboard on one and have it pass jobs to the other nine. All ten share a directory on one of them with all the images in.
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by asb » Mon Jun 11, 2012 2:25 pm
You can easily hook up a bunch of USB SD card writers to a couple of hubs and have a script write the image to them. It worked reasonably well, without the need to invest in a commercial SD card duplicator. I'll share my script at some point (we used it to write the SD card images that got sent out to journalists), but there's nothing particularly special about it.
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by abishur » Mon Jun 11, 2012 2:30 pm
Off the top of my head here.

Once we figure out how to use our own boot loaders, it would be possible to hold a specific key combination on boot up which would in turn download and write a fresh image onto the SD card. When I worked IT for a school district in my area we had this set up for the desktop PCs in the area. Every year we'd go around to each school and re-image every PC.

Doesn't RASPBMC do something similar to this on it's first boot? It downloads an image to install onto the card?

If this works than ideally you'd only have to manually re-image the cards that got royally messed up.
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by mraltair » Mon Jun 11, 2012 2:34 pm
At our school we are lucky, we have just gone through an upgrade to all our PC so they all have card readers in and we've left them all open for use with cameras.

I'm not sure if the Pi will feature in IT lessons here (well, they've not told us anything) but would it be feasible to have the older kids (yr9-13) create their SD cards and have them do a second one 'for practice' and use those extras for the younger kids? I guess this hinges on the size of the school and the curriculum used up through the years. I've also not got a Pi to create my own SD yet so I don't even know the process. :roll:
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by nick.mccloud » Mon Jun 11, 2012 2:55 pm
The point of the Pi is that the tech's don't even get a look in - if the tech's do the leg work, how will the kids learn about setup?
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by Gert van Loo » Tue Jun 12, 2012 10:22 pm
The answer is straightforward: Use a Raspi!
I looked at SD-card gang programmers in November last year as the plan was to sell pre-programmed cards through the foundation shop.
I could not find them but any gang programmer costs thousands of pounds.
Solution: for 500 pounds you can buy ~20 Raspberry-Pis.
Now "all" you need to do is make a special "SD-card copy image":
So you boot first from an SD-card but put the swap space and everything you need on a USB stick.
Next you can plug in an empty-card and have a default image on that same USB stick to put on the card.
Run 20 of these in parallel.
You can also put the image on a central network resource but you need A LOT of network capacity to feed
20 boards all writing at maximum speed to an SD-card. So I think the USB system is the simplest.
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by asb » Tue Jun 12, 2012 10:29 pm
Gert van Loo wrote:The answer is straightforward: Use a Raspi!
I looked at SD-card gang programmers in November last year as the plan was to sell pre-programmed cards through the foundation shop.
I could not find them but any gang programmer costs thousands of pounds.
Solution: for 500 pounds you can buy ~20 Raspberry-Pis.
Now "all" you need to do is make a special "SD-card copy image":
So you boot first from an SD-card but put the swap space and everything you need on a USB stick.
Next you can plug in an empty-card and have a default image on that same USB stick to put on the card.
Run 20 of these in parallel.
You can also put the image on a central network resource but you need A LOT of network capacity to feed
20 boards all writing at maximum speed to an SD-card. So I think the USB system is the simplest.


As much as I like the Raspberry Pi as the solution to all problems, it is cheaper to just buy hubs + USB SD Card writers :). The SD card images that went out to press were written about ~15 at a time using such a setup.
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by shirro » Tue Jun 12, 2012 10:51 pm
What school techs?

Techs are generally shared between a number of schools here and their hours diminish. Technology should be getting more reliable and easier to self maintain.

OLPC Australia give kids certificates once they have the skills to do maintenance. I don't think the Pi is anywhere near as complicated. Kids can for the most part fix them by re-imaging. http://edu.laptop.org.au/participate/xo ... ic-program
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by SN » Tue Jun 12, 2012 10:56 pm
So will there be a new role for a class member - the "SD Card Monitor" ? :lol:
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by liz » Tue Jun 12, 2012 10:58 pm
Remember the Leeds school masterclass that Eben took a few months back? (There's video on the blog.) We'd expected SD cards to be ready when we got there, but it turned out that the guy who was meant to be preparing them had just dragged and dropped in Windows, so none of them were partitioned correctly. Cue massive panic; the kids had all arrived already, so we had to move fast. (Thankfully there was a cafe, some interesting grown-ups to talk to and a lot of cake.)

It took about 15 minutes using two PCs to download windd (or similar - I was in the cafe making nicey-nicey with the kids) and make 15 working SD cards using the data on the one known-good card I happened to have in my handbag. So it's not going to be a total nightmare for technicians - just a few hours' grind at the start of the school year - or, if they're smart, they'll build it into a lesson and make the kids do it.
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by mahjongg » Tue Jun 12, 2012 11:40 pm
If you are going to use raspi's to write cards, then they must be connected to external USB card writers, as currently there are no distro's that run completely in RAM, and so can "unlock" to raspi's SD card slots, except the "emergency boot image", and I'm not sure that one is up to the task, besides, there is probably not enough RAM to contain the whole content of the image to be put on a card.
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by jecxjo » Wed Jun 13, 2012 12:40 am
For the super nerdy...here is a suggestion.

Create an SD card image that boots the kernel and then the RFS via NFS. At that point you should be able to remove the current SD card since the kernel would be loaded into RAM. Put in a blank SD card, run a little script that DD's the image from NFS to the card and Bob's your uncle. This only requires one "boot" SD card that everyone could share and an NFS server (which could be running on the teacher's Pi)

Now I haven't tried it on the Pi but I do this all the time with other boards like this.

EDIT: Sorry mahjongg didn't read your post, suggesting the same thing.
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by nick.mccloud » Wed Jun 13, 2012 9:57 am
liz wrote:Remember the Leeds school masterclass that Eben took a few months back? (There's video on the blog.) We'd expected SD cards to be ready when we got there, but it turned out that the guy who was meant to be preparing them had just dragged and dropped in Windows, so none of them were partitioned correctly.


Oh the irony!
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by truan » Wed Jun 13, 2012 6:37 pm
mahjongg wrote:If you are going to use raspi's to write cards, then they must be connected to external USB card writers, as currently there are no distro's that run completely in RAM, and so can "unlock" to raspi's SD card slots, except the "emergency boot image", and I'm not sure that one is up to the task, besides, there is probably not enough RAM to contain the whole content of the image to be put on a card.


The installer for raspbmc does something close though. the initial image boots the pi, puts itself in memory then downloads and sets up raspbmc on the sdcard. Add a step to wait for you to swap the cards and press a key and it could do it couldn't it?
One sdcard with the master image, boot the pi with that, swap for a blank sdcard, and move to the next.
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by piglet » Wed Jun 13, 2012 8:03 pm
mahjongg wrote:If you are going to use raspi's to write cards, then they must be connected to external USB card writers


I tried this at work today in my lunchtime. Writing from the 2012_06_10_spindle_wheezy_public_alpha.img image on the SD card to a card writer on USB hub took a very long time - and I had to do it 4 times before it wrote properly. Cheap card writer...jog the desk and the card connection is lost.
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by bitplane » Mon Jun 18, 2012 2:18 am
This gives me an idea...

Raspberry Pi: £30
10 port USB 2.0 powered hub: £10
11x USB card reader/writer: £11

Add LEDs to GPIO, make a case from lego, sell on eBay for £100 each! :lol:
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