LWN: Comments on "Open Firmware is now free"

Open Firmware is now free

giraffedata — Tue, 28 Nov 2006 07:04:04 +0000

I care about closed source for all the normal open/close reasons. The main reason's that affect me:
...
Most of this is just not cost effective under the ancient proprietary system in use today for BIOS.

Those are all good reasons to care about closed source of today's BIOS, but not relevant to the point to which you are responding. That point is that with a small initial program instead of what we have today, people wouldn't care about having its source code. Such a boot program wouldn't be involved in any of the issues you list.

Getting back the OF question: The reasons listed are not only good reasons to have open source for the code that handles those things, but also for being able to update that code easily, for example with a 'cp' shell command instead of an arcane BIOS flash procedure. And in a way that if you screw it up, you can easily repair the damage. Open Firmware doesn't do any better than today's BIOS in those areas, and in fact is worse because there's so much more code in there that you'll want to update.

Open Firmware is now free

jimwelch — Mon, 27 Nov 2006 20:23:21 +0000

>> I don't think they would care that it's closed source.

I care about closed source for all the normal open/close reasons. The main reason's that affect me:

1. BUGS - some of my "old" computers don't do big disks.
2. DRM - some talk of only allowing certain OS's on a unit.
3. Features - LVM, boot from flash (missing on my old units), the next big hardware item (firewire disks).
4. Lack of support from the vendor to fix the above problems for old units.

Most of this is just not cost effective under the ancient proprietary system in use today for BIOS.

Open Firmware is now free

giraffedata — Mon, 20 Nov 2006 04:41:04 +0000

It's not that Open Firmware is "better" than GRUB. It's that if you have open source firmware (be it BIOS, Open Firmware, or "other" like u-boot), GRUB is unnecessary.

OK. But I sensed that was being used as a argument in favor of switching to Open Firmware from what we have today. I don't think it's a good argument. In fact, even if I had Open Firmware, I'd probably have it load Grub from my disk.

The "small initial program" you talk about is an accurate description of today's BIOS or Open Firmware

I meant to refer to something smaller than today's BIOS and much, much smaller than Open Firmware. I can understand why people want an open source alternative to the BIOS boot loader we have now, but if it were as small as I would like, I don't think they would care that it's closed source.

For example, we could add an LVM driver to the firmware itself

I would rather add an LVM driver to something more mutable than flash, such as the standard USB flash drive I mentioned. That's why I don't care if I have open source firmware (if "firmware" means what lives in the flashable read-only memory that sits in the main address space at boot time).

"lower-level BIOS"

hollis — Sat, 18 Nov 2006 17:40:53 +0000

Open Firmware comes in ROM, so in that sense there is no "separate" firmware.

Of course, inside Open Firmware you have different components: the Forth interpreter and the low-level firmware (responsible for initializing the memory controller, discovering PCI devices, etc) are obviously separate. As a systems vendor you would naturally use the same Forth interpreter and combine it with a different low-level firmware for each system.

By the way, "BIOS" is just the name for the standard PC firmware interface. The generic term is "firmware". :)

Open Firmware is now free

hollis — Sat, 18 Nov 2006 17:33:48 +0000

It's not that Open Firmware is "better" than GRUB. It's that if you have open source firmware (be it BIOS, Open Firmware, or "other" like u-boot), GRUB is unnecessary.

Don't forget that flash is mutable.

The "small initial program" you talk about is an accurate description of today's BIOS or Open Firmware, yet for some reason many people are interested in open source firmware instead. Firmware access would mean we could fix bugs and add features instead of awkward workarounds at higher levels of software. For example, we could add an LVM driver to the firmware itself, and not have to worry about loading successive "stages" like GRUB must resort to.

Open Firmware is now free

giraffedata — Fri, 17 Nov 2006 21:54:43 +0000

Seems redundant to use two separate BIOSes

A good reason to have two separate programs is the same thing that led to having two separate programs (BIOS and OS) on the first ISA computers: BIOS is married to the hardware and OS is married to the application. You mix and match in order to have any combination of application and hardware.

When OF runs without a separate BIOS, it contains a machine-type-dependent BIOS. The only difference really is one of packaging and naming. To me, it makes the most sense to package bona fide BIOS with the hardware and package everything else separately, for more flexibility and better compatibility.

In the case of Sparc, Mac, and IBM System P, the OF instance is designed for a particular machine type and supplied with that machine, so there's no reason to have a machine type compatibility layer (BIOS) under it. But if you're going to separately distribute one OF to run on a variety of machines distributed by someone else, separate BIOS makes a lot of sense.

Open Firmware is now free

giraffedata — Fri, 17 Nov 2006 21:39:50 +0000

Regardless of familiarity with the language, I don't see how Open Firmware is better than Grub. I'd rather have just enough code in ROM to load the next stage from a more mutable device, which is what we typically have today.

A big part of what OF is is pluggable device drivers to let you boot from lots of different kinds of devices. I'd rather just see a program that can boot from only one kind of device -- a removeable, standard, USB flash drive. You can put as much intelligence on that drive as it takes to boot the next stage from whatever you want, so instead of today's POST or OF, I would probably put a tiny Linux on it. In some cases, I wouldn't even need a next stage.

With such a small initial program, people wouldn't have much interest in seeing its source code or updating it; it would be equivalent to code inside the network adapter, but even less interesting.

Open Firmware is now free

salimma — Fri, 17 Nov 2006 02:09:24 +0000

Do Sun and Apple (pre-Intel) use OpenFirmware entirely, or do they also use a separate lower-level BIOS? I'm curious as to whether the next version of OLPC will switch to OpenFirmware entirely. Seems redundant to use two separate BIOSes apart from for easing the transition.

Open Firmware is now free

jg — Thu, 16 Nov 2006 19:40:42 +0000

We aren't using grub or lilo on the OLPC system.

Then again, we're not trying to boot multiple operating systems (nor will vanilla Windows boot on our hardware, due to lack of VGA support in the BIOS, since the code was not free).
- JIm

Open Firmware is now free

hollis — Thu, 16 Nov 2006 16:36:16 +0000

All open source firmware could remove the need for bootloaders like LILO or GRUB, because you could simply extend the firmware to provide the functionality.

In practice, I suspect bootloaders will always exist on Open Firmware systems as long as people understand C better than Forth.

Open Firmware is now free

rfunk — Thu, 16 Nov 2006 14:37:15 +0000

It's worth noting that Macs have used OpenFirmware for some years now.

OpenFirmware could also remove the need for GRUB and LILO, correct?

Emacs lisp

felixfix — Thu, 16 Nov 2006 07:27:00 +0000

Yes, since I do almost everything from Emacs, it does qualify as boot firmware, for sufficient values of "boot" and "firmware" :-)

Open Firmware is now free

flewellyn — Thu, 16 Nov 2006 05:37:26 +0000

This is wonderful, not only for the listed reasons, but also because Open Firmware, and Forth,
are just fun to mess around with. What other boot firmware can you write Tower of Hanoi
programs in?