[Oberon] Re (2): Re (2): UEFI
joerg.straube at iaeth.ch
Tue Jun 15 20:12:36 CEST 2021
The functionality of UEFI is somewhat comparable to BootLoad.Mod in FPGA Oberon. BootLoad resides in ROM and is the first code the RISC-5 CPU executes after power up. It loads the inner core from disk to adress 0000 and jumps to 0000.
The inner core then loads the outer core. And the outer core loads the Oberon system.
> Am 15.06.2021 um 19:58 schrieb D EMARD <vordah at gmail.com>:
> I feel need to add some comment,
> there's possibility to get rid of UEFI
> and write linux kernel or open source UEFI
> replacement, although the process is
> really for advanced users and
> selected/compatible hardware
>> On 6/15/21, Liam Proven <lproven at gmail.com> wrote:
>>> On Tue, 15 Jun 2021 at 18:11, <peter at easthope.ca> wrote:
>>> IME is separate from UEFI. Correct?
>> Yes. Separate from and totally unrelated to.
>> UEFI is system firmware: the onboard software in non-volatile memory
>> that allows the computer to start up, perform some self-tests,
>> initialise the hardware and load an OS. On x86-64 PCs, it replaced the
>> traditional PC BIOS. On Intel Macs, it replaced OpenFirmware as used
>> on PowerPC Macs. It runs on the main CPU when the computer is powered
>> on, and after the computer boots an OS the UEFI is no longer doing
>> anything very important -- the OS calls it for some power-management
>> functions but little else. Some OSes of course do not have any power
>> management so do not even do this.
>> It is extremely roughly analogous to the starter motor in a petrol or
>> diesel engined vehicle.
>> Some form of firmware is an absolute requirement and without it a
>> computer cannot boot an OS. It cannot readily be replaced.
>> IME is an embedded system-management OS running on a dedicated,
>> separate processor within all modern Intel CPUs. It is intended for
>> remote management of servers. It is running all the time that the
>> computer is on, but does not directly interact with the OS. Mostly,
>> older computers did not have this at all -- it used to be purely for
>> remote management of server hardware.
>> It is extremely roughly analogous to the little CPU managing the
>> electronic dashboard of a modern car: it may be able to control some
>> functions of the vehicle (entertainment system,
>> heating/air-conditioning, maybe even indicators or reversing cameras)
>> but it is not powering the vehicle in any way and it is entirely
>> possible that it could be ripped out but still leave the vehicle
>>> IME provides another way that an external party might access a machine
>>> for a purpose unwanted by the machine owner.
>> It does.
>>> UEFI imposes another layer of complexity not intrisic to the user
>>> objective but requiring attention for the machine to serve a purpose.
>> Not really, no.
>> Very early minicomputers had no firmware at all, but had toggle
>> switches on the front panel so that you could directly enter
>> instructions in binary and place them in memory. To load an OS or
>> program from tape, you had to manually enter in a boot loader, dozens
>> or even hundreds of instructions.
>> This was very tedious and required careful expert knowledge -- very
>> few people were able to do it from memory, but it did happen.
>> It took 10-15min of work to enter the code and then you could start your OS.
>> Modern computers have no front panel like this. Without some firmware
>> in a ROM chip, you could not use the computer _at all_. The firmware
>> is what loads your OS from disk.
>> You need it. UEFI is the modern replacement for what 20th century PCs
>> used to call the BIOS.
>> It is not optional. It cannot be replaced with anything else.
>> Some late BIOS-era computers, e.g. early Lenovo Thinkpads, can have
>> their firmware replaced with a FOSS equivalent:
>> You need to open up your machine and connect another computer to it in
>> order to be able to write code to the flash ROM that the manufacturer
>> did not authorise.
>> I do not know of any UEFI machines where this is possible. (I could be
>> wrong.) I don't think I know of any new hardware that comes with
>> Coreboot or similar instead of UEFI. (I would be happy to be wrong.)
>> So, whether we like UEFI or not, it is here, it is part of all native
>> 64-bit PCs and Macs, and it is part of the computer industry. We have
>> no choice over this.
>>> In the Oberon philosophy, neither of those is desirable.
>> IME may not be. (Choose an AMD machine if you prefer.)
>> UEFI is not a choice; there is no other option if you want a modern
>> x86 computer.
>> The Raspberry Pi does not include UEFI but it does have very simple
>> firmware. The Zero and RasPi 1/2/3 loaded this from microSD card. The
>> RasPi 4 has a tiny bit of it onboard.
>> However, in the RasPi, the ARM CPU is not the master controlling CPU
>> of the computer. That is the GPU. The RasPi GPU is what boots the
>> computer: it loads `kernel.img` from micro SD, puts it in RAM, then
>> the GPU starts the ARM core and hands control over to it.
>> The GPU runs ThreadX and again there is no choice about this. There
>> was a FOSS effort to replace it, but it stalled and is incomplete.
>> You can put UEFI onto a MicroSD card and boot that if you wish, then
>> load an OS from it, but this has limitations.
>> However, you can run whatever OS you want on a RasPi. Alongside dozens
>> of Linux distros, it also runs Plan 9 (that is, Unix 2.0), OpenBSD,
>> FreeBSD, NetBSD, and RISC OS Open.
>> RISC OS is totally non-Unix-like and is essentially a 32-bit port of
>> the early-1980s Acorn BBC Micro's MOS operating system to the newer
>> Archimedes range. RISC OS was the first ARM OS and is today FOSS.
>> Interesting historical footnote: Acorn developed & took RISC OS to
>> market because its internal effort to build an all-new OS failed. This
>> OS was to be called ARX and was written in Modula-2. So, in a way,
>> Oberon and A2 are much like what Acorn _intended_ the Archimedes to
>> Liam Proven – Profile: https://about.me/liamproven
>> Email: lproven at cix.co.uk – gMail/gTalk/gHangouts: lproven at gmail.com
>> Twitter/Facebook/LinkedIn/Flickr: lproven – Skype: liamproven
>> UK: +44 7939-087884 – ČR (+ WhatsApp/Telegram/Signal): +420 702 829 053
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
More information about the Oberon