Raspberry Pi use in education: boot times, repeatable boot

The OS`on those old machines was measured in tens of kilobytes, and was loaded from ROM over a parallel bus, as if it were RAM. Modern OS images are many megabytes and, in the case of the Pi at least, are loaded over a serial bus, albeit a fast one.

The fastest PC I've ever seen boot was a Toshiba notebook booting DOS

3.3 from a ROM. Ten seconds or so to be usable.

It's cheap enough to issue each child with their own OS image on an SD card image, which would prevent any problems with malware, as long as the Pi was powered off netween uses and has no storage permanently attached. The SD card could be used to keep each student's data on, too. Keep spares in your desk drawer, and reload them with a clean image when you get time.

It needs a custom boot image on the SD card, but yes, a Pi can be booted from a network.

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Tciao for Now! 

John.

Standard Raspbian with a few tweaks boots in under 30 seconds. It's not the 1 seconds of the Apple II, PET or BBC Micro (plus tube warm up times!) - mostly because it's doing a billion more things to actually boot.

Quickest I can boot a Pi into anything usefull is about 5 seconds to load Linux, do the bare minimal setup to initialsie the keyboard then launch (my own) BASIC.

Pretty easy as (in Raspbian) the sudo command is passwordless by default. That's easy to fix though. But just ask the kids to bring in their own Pi's... or SD cards.

The Pi must boot off SD card. It's on-chip ROM has just enough code to load a file off the SD card and no more. However that file can load the Linux kernel which can then have its root filesystem NFS/iSCSI mounted off a central server if required. Might more bother than its worth...

Gordon

[ ... ]

How about RISC OS, very widely used in the era you refer to? It is still in active develoment and runs well on the R-Pi; mine boots in about 40 secs. Plenty of educational and other applications too.

See

and

Brian.

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Brian Carroll, Ripon, North Yorkshire, UK   
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Dzieki, James, za post o tresci:

The Pi isn't a speed daemon, really. Pidora (which is quite old) boots in almost 24 seconds:

Startup finished in 1989ms (kernel) + 21392ms (userspace) = 23381ms

2 seconds for kernel initialisation is A LOT. Modern Linux laptops boot full graphical session in 4 seconds.

--
Tomasz Torcz                "Funeral in the morning, IDE hacking 
xmpp: zdzichubg@chrome.pl    in the afternoon and evening." - Alan Cox

I just timed mine, a 512 MB RPi model B running fully updated Raspbian as of about 14:00 this afternoon, at 37.2 seconds to boot from cold.

I run mine headless and have a rocker switch in the power cable, so I started the stopwatch as I snapped the power switch on and stopped it when all the LED flashery had stopped. After the yellow LEDS turn off and then on again as a block the last few flashes are from the green LED, which then stays off: thats when I stopped the watch.

That seems to me to be an acceptably fast boot unless you insist on comparing it with something like, say an MC6809 coming up to the first screen when the ROM-monitor, which clears the screen and prompts for input is burnt into an EEPROM that's hard wired into the MPU's address space.

Here's a slightly more realistic comparison: I also have a Binatone B.350 satnav. It is based on an Atlas II chip running at 300MHz (ARM 9?) and with 64MB RAM. This boots into WinCE 5.0 in 15.85 seconds and then takes another 33.29 seconds (and four screen taps) to load LK8000, the moving map glider navigation program I run on it. Since I was hovering waiting for the prompts, I doubt that the screen taps added more than 2 seconds to the total start-up time of 49.14 seconds.

HTH

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martin@   | Martin Gregorie 
gregorie. | Essex, UK 
org       |

RISC OS with network: 24 seconds RISC OS without network: 14 seconds (it's waiting for DHCP that takes the time)

I'm powering my Pi from a 40" LCD monitor that takes 5s to display from power button push to video, so the apparent time is only 9s.

You can boot Pi Linux with a root filesystem on NFS or similar - you still need an SD card, but the SD just needs the kernel. The Pi doesn't have the SD write protect switch wired, otherwise you could set the card read-only.

Similarly, RISC OS only writes to the card when you tell it, and is designed for use with floppy discs when you could remove them at any time. Indeed you can pull out the SD at any time and use the machine quite happily, and it'll prompt if it wants the SD for anything. So it's quite common to simply pull the plug and it generally doesn't mind.

Theo

On Thu, 25 Jul 2013 19:12:34 +0100, "James Harris \(es\)" declaimed the following:

Understudy to Ada Lovelace, I take it?

Well, my "Trash-80" (a cognomen that only really should apply to the original, and the model II [whose power supply and monitor shielding were so bad that every floppy access caused the display to shrink and wobble]; my Mod III/4 [a Mod III upgraded to Mod 4 processor board but keeping the larger Mod III power supply] was anything but "trash") was also fairly fast when using the ROM boot -- it did take a few seconds longer once I went to floppy OS.

I suspect that any modern OS will take some time -- even if SD cards are faster than 80's floppy drives. Remember that those early machines were monolithic -- ONE process, period. No process scheduler, no memory protection (no virtual memory! -- and what memory one had is unavailable these days*, and minimal interrupt handling (keyboard buffering, and likely serial port -- disk drives may have been "programmed I/O", using polling loops or whatever in direct response to an I/O request).

It's Linux... If the student does not have ROOT access they'd probably have to use another computer to corrupt the SD card.

That would negate any use of the device for homework.

* I just pulled the memory expansion from my Amiga A-1000... a $400 box filled with $400 of chips -- 32 512x1 DRAM -- these days you can't even find a CF card smaller than a few GB... A Parallax Propeller has 8 "cogs" each of which have 2kB onboard.

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	Wulfraed                 Dennis Lee Bieber         AF6VN 
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

Or the SD card could have a very simple network bootstrap to do the main boot from a server.

-michael - NadaNet 3.1 and AppleCrate II:

Well, let's just say she was past her best by then. ;-)

James

I doubt that's relevant, media access times being what they are. I suspect the time taken for Linux to boot is mainly due to probing and waiting for responses from devices - some of which do not exist - but I could be wrong.

That would be good.

By the way, does anyone know whether Pis are supposed to be bought by the school or the pupils? I imagined the idea was that a school could afford to equip a lab with computers (and old tellys...?) but maybe the idea is that pupils' families buy their own?

James

30 seconds is still too long. ..... (IMHO)

Sounds like the slowness is not due to the Pi but due to the OS. Good!

James

14 seconds sounds good. What did you have to do to tweak this? Brian reported (on this thread) a RISC OS boot in about 40 seconds.

James

If you're using TVs for monitors then it must be a home computer, surely? Rather than just sticking a bunch of them in an IT suite you could have more fun incorporating them into e.g. physics experiments, or building a cluster, or remote hardware control ...

The SD is the ideal boot method, Give each pupil their own SD card and the R Pi is a "new machine", regardless if the previous pupils "corruption" or "modification. Custom versions of the OS are easy to produce.

I produced one for our school so that the R Pi could be place on the network (in theory physically anyway) and accessed by pupils from a PC, iPAD etc. running an XWindows Client and/or SSH Client. No new HMDI monitors etc. R Pis can be secure and pupils can be in any IT room or even an ordinary room with a laptop or iPAD.

The image includes a webserver, FTP server, as well as the X server and SSH server.

I've made it available to pupils for use on their home R Pis and to anyone else who wants it FOC.

I don't teach IT, it was a favour to a colleague, my subject is Mathemathics.

...

Imagine the start of a class: "Right, children, plug in your SD cards and settle down. What's that Johnnie, you've left your card at home again? And of course it had your data files on it. Emma, how did you get your card in that state? You should have kept it in the box we gave you. Don't plug it in. You'll both have to get new cards. Unfortunately you'll have to redo the work you saved on them last time. Settle down the rest of you I'll be with you in a minute. Remember to set the date and time once your machine has started. Has everyone got the machines booted? You haven't. What's wrong? I don't know what that message means. You'll just have to sit quietly for a moment while I get the class started. I'll come back to you in a moment...."

By contrast, if all the Pis booted from a server and the kids stored their data on the server none of the above would happen.

James

But what would that teach them? :-)

Actually we are moving from such a system (data on server) to self-managed storage (usb key) for a PC training course environment.

Storage on server appears to be attractive, but students/pupils cannot work at home, and accounts need to be managed.

I agree with you that there is the potential of lost/forgotten items. We'll see how it works out in practice. (it wasn't my idea, storage on server was)

Maybe USB sticks would be better for people to store data on than SD cards. Of course, once keyboard and mouse are connected the Pi has no USB ports left.

An external, powered USB hub would be good but adds to the cost.

I believe some keyboards have inbuilt USB hubs. If the Pi has enough power to drive them the USB stick could be plugged into the keyboard.

James

This may not be "fashionable" but taking responsibility for their work, including having it with them, is part of the learning process. Not having an SD card is no different to not having a Maths book, you have paper (another card) to hand and move on. You don't let it disrupt the lesson.

Booting a room full of machines over the network all at the same time would probably be slower than the SD card route, remember the network machines will have other tasks as well.

If you are a teacher, perhaps your lessons are different but certainly my experience tells me that this isn't an issue.

Certainly, if you always "spoon feed" pupils then you are not preparing them for the real world.