Boot from a 16MB SD card?

I’ve just spotted the latest post on the Raspberry Pi website: Boot from a 16MB SD card – and I’m a bit surprised it’s not been commented on here.

I’ll just leave this quote out there:

You’ll need a USB memory stick too, large enough to fit your operating system on, because 16MB isn’t going to cut it.

Is not a problem, I think. I boot my first Beagle from a 32MB Card and there is enough space free.

…With a very minimal amount of work, he was able to put all the pre-boot files (9MB) for Raspbian

“Pre-boot” – hmm, with absolutely no work whatsoever a RO user manages to load an OS with GUI from 4MB, add fully populated boot and a copy of the DDE plus the source to !PC etc and you can push that to 140MB

I could boot a fully functional (but essentially resource free) version of RISC OS on an SD card half that size. Around 4MB or so for the RISC OS image, and the same again for all the Pi startup stuff.

It isn’t just “doable”, it’s a simple copy’n’paste operation.

Give me a 256MB card and I’ll give you a complete RISC OS setup with apps and stuff. Double that and we can throw in the complete build environment so the OS can build itself.

That’s probably why nobody here commented on the article. To us, this just isn’t news. ☺

A Pi SD card has to have start.elf as well as the ROM and !Boot.
8MB would need (if at all possible) a very cut down !Boot. I think 16MB should be straight forward with a standard !Boot.
I’ve ordered an 8MB and a 16MB SD card!
Edit: Written before seeing Rick’s post.

Is not a problem, I think.

Exactly the reason I thought it worth pointing out. :)

Chris:

I’ve ordered an 8MB and a 16MB SD card!

Blimey! Who on Earth is still supplying cards that size?

I don’t even remember MMC cards of that low a capacity. I did buy a 64MB one some years ago for when I was developing SD card read/write for the BB.

The 32MB card has arrived. I can HForm it and read/write but SystemDisc fails to partition it. I suspect Ben never expected anyone to use such a small card. I’ve emailed him.
I’ve had a look and the Loader partition contents should fit in a 5MB partition! So has anyone got a 8MB SD Card to try?

I can HForm it and read/write but SystemDisc fails to partition it. I suspect Ben never expected anyone to use such a small card. I’ve emailed him.

I have the same problem with my 32MB card and emailed Ben… ;-)
At this time I try a complete FAT-formated… Bootfiles + HDImage content… not really free space, but it works (I try Pandora)…
DamnSmallRISCOS ;-)

I’ve received the 16MB card and now have an 8MB card on its way from Canada.
Has anyone got a minimal Pi friendly $.!Boot ?
I could do one but don’t want to reinvent the wheel.
I’m looking for one <3MB.

The 8MB card has arrived but is IIRC actually only 6.68MB:-(

Help wanted:
We’d love to get some good publicity out there for RISC OS but with all our plans for the Pi Compute Module we just don’t have the time to set up a minimum boot image. Can someone help?

For the 8MB card we will need use a single FAT partition.
start.elf, RISCOS.img etc will occupy over 5MB so can any one produce a very severely cut down disc image.
My thoughts/suggestions:
No $.!Boot structure but a RISC OS 3 type disc Image with !System, !Scrap in the root directory.
Remove support in !System for anything other than RO 5.21 (Use a RO3 !System structure?)
Having networking running (ShareFS) would make it massively more usable but I suspect may need a bit of work to do so (Command line setting of ip address/mask?)
No !Fonts (just use the ROM fonts)
An obey file to copy !Scrap to RAM Disc.
…

For the 16MB card life should be a lot easier
We started cutting down a standard Pi !Boot but that has a lot added, so I thing starting with a generic RO5 !Boot would be a lot easier.

Anyone fancy the challenge?

You could always download RISC OS Pico and swap the ROM image with the latest RISC OS Pi beta image. That’d get you most of the way there.

What is it that you want? The Pico build (4.5 Mbytes) will start up on the Raspberry Pi with no desktop environment but a fully functional RISC OS machine starting up in BASIC.

If you take the standard HardDisc4 image and remove the following directories:
$.!Boot.RO500Hook.Res.*
$.!Boot.Resources.Configure
$.!Boot.Resources.!ThemeDefs
$.Printing
$.Utilities
$.Diversions
then you get 2427k (zipped) that could be copied into RAMDisc and unsqueezed on start up to boot from RAMDisc with a full(ish) desktop.

In any case you don’t need to buy small SD cards (to test it that is), just create the SD card image for a small card and write it to a big card. If it works then you know that it works.

If you must have everything in a single FAT partition, then you will need to copy a squeezed HardDisc4 to RAMDisc and expand it there and boot from it so that you will have the correct filetypes anyway. Getting that emthod to work (in principle) is step 1. Step 2 is to keep cutting stuff out of HardDisc4 until you have what you want – sufficient of what you actually want and sufficient of what you don’t want but find you need for it to work.

Then turn the cut down HardDisc4 image into a util file that can be copied to RAMDisc and run (to expand it) and bingo!

An obvious question – are such small SD cards so cheap that they could be given away (and if so are there many of them out there anyway or will the supply quickly dry up)?

I feel it’s the achievement that gets the kudos, not the practicality. What’s the point if there’s not much more space a user can add to. However, when applied to a larger (and more available) card, it shows how sleek and efficient an operating system could, (and possibly should,) be.

Whilst kudos is certainly a big part of it I think making it as usable as fairly standard RISC OS computer I think would be the most impressive. So for me that rules out Pico.
RISC OS 3’s main disc components !System !Scrap etc fits uncompressed onto an 800K disc and if you have networking working then everything else can be stored elsewhere so I’m confident it can be done!