Diskless booting of Amiga

[Mrs Beanbag]

maybe a custom ROM could be made. that could be interesting actually. You could boot from the network if you could do that.

[Mrs Beanbag]

Someone who was developing the AROS 68k ROM (I forget who) once told me he accidentally made the RAM: disk bootable once and it booted it. You can also boot from RAD disk (I tried this once, I effectively net booted using a boot floppy to pull an image of my workbench partition off the network and unpack it into RAD). So yes it is possible with only small changes, since a device doesn't need to correspond to a physical drive to be bootable.

All you need is a bootable disk with LoadWB on it to get a basic workbench, which is only a few kb. I suggested the idea of a ROM disk once. It would be interesting to be able to go straight to workbench from the boot menu, and could be very useful. Especially if there were room in ROM for such things as AmiTCP.

[Mrs Beanbag]

there is also this:
http://eab.abime.net/hardware-mods/66815-custom-flashrom-design-amigas.html

[Mrs Beanbag]

ROM: drive wouldn't need to take up memory, you could essentially have a RAM-like, read only drive pre-populated in the ROM, mount that and boot from it. So you could put anything you wanted in there.

[Mrs Beanbag]

Guess I'm missing something? but why would you want to?

There are many reasons. It is often done to install operating systems on computers that don't have optical drives, especially laptops.

I wished I could do this when I upgraded my A1200's HDD to a SSD, I had to make a boot floppy with a minimal AmiTCP/FTP on, which was a nightmare since my floppy drive was playing up.

[Mrs Beanbag]

you can indeed get to a shell window (hires, 640x256 I think) just by making a blank disk bootable. If you put the loadwb command on there as well and a startup-sequence, you can get a workbench as well. Workbench is in ROM and only needs a function call to activate it! It isn't very functional without all of the system tools and utilities that come on the workbench disk, but you can click on disk icons and run programs from it, so you could run software that wasn't on bootable disks.

Disk blocks are a feature of physical disks, there is no reason a RAM/ROM filesystem has to use them, although it might be convenient to do so. I've no idea how the RAM: drive is formatted in memory.

In the ROM my guess is you could have a structure internally the same as a RAM drive with files on it, and then mount it the same way you'd mount RAM or RAD, only it would have things on it already. So I think it would be very simple to do. I should get the AROS 68k source and have a play with it on an emulator.

[Mrs Beanbag]

I was wondering just now, presumably it should be possible to make a NFS device that survives a reboot like a RAD disk does. That could be powerful.

[Mrs Beanbag]

There is already an open source Network File System for Amiga, here:

http://sourceforge.net/projects/anfs/

I wouldn't know how to get it into a ROM image though.

[Mrs Beanbag]

@Mrs Beanbag: You could easily put everything you need for NFS into a RAD disk and reboot from that. No real need to make the device itself survive reboot.

Of course. But the aim is to be able to boot from the NFS. And that, without having any disk to boot from first. If we have NFS on a disk we don't need to put it in RAD afterall! Or if it is in ROM...

If one had in ROM a basic network capability, and a command line that requires no boot disk (RAM drive can be booted), the NFS driver could be pulled from the network first, mounted (reset-proof) and then booted.

[Mrs Beanbag]

Just got message from someone on EAB, Toni Wilen has made a Rommable version of PFS/3, see here:
http://eab.abime.net/881562-post29.html

[Mrs Beanbag]

I think the main requirement for making code ROMmable is that it be pure. In other words it doesn't store variables inside its own code but always uses the stack or allocated memory. Which is kind of obvious, really. If something is in ROM it can't write to itself so it would get a bit stuck. Apparently anything written in C should be safe as long as you don't use global variables. I have been moving towards this approach in my own code, I should aim to make Mr Beanbag "pure" as a matter of principle.

[Mrs Beanbag]

I don't know, try this on it, see if it works:
http://aminet.net/package/util/boot/LoadModule

Whether that is enough for it to survive a reboot remains to be seen. And I doubt it would be bootable without modification in any case.

[Mrs Beanbag]

See also this thread that I started on EAB, (well, that a mod started by moving my posts! which was fair enough)
http://eab.abime.net/support-other/69540-bootable-network-file-system-rom-amiga.html

[Mrs Beanbag]

I don't know what is meant by a bootblock for non-block devices but you can definitely boot from RAD which isn't a block device.

NFS doesn't need TCP? Really?

[Mrs Beanbag]

RAD *is* a block device.

Is it? I wonder why. It doesn't need to be.

There are two different types of DOS devices: block  devices with (usually) a physical structure underneath and a file system  on top, and file handlers without, like a RAM disks or a network  redirect. Take a look at the old mountlist entries and you get the main  idea.

Are RAD and RAM different internally then?