Linux from Scratch

Linux from Scratch

[Jim Gifford]

I have updated my RaQ2 build for Linux from Scratch to most of the 
latest packages for the RaQ2. A question was raised by some other 
memebers of the Linux from Scratch group, that frankly I didn't have the 
answers for. I appreciate your feedback on these questions.

1 - Will the build method I have currently work with any MIPS processor 
based machine, with the exception of the bootloader?

2 - Is there a bootloader for MIPS that will work on every machine, or 
is different for every MIPS based machine's firmware? If so any examples 
out there how to implement?

Thank you for your time and assistance

-- 
----
Jim Gifford
maillist@jg555.com

Re: Linux from Scratch

[Stuart Longland]

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Jim Gifford wrote:
> I have updated my RaQ2 build for Linux from Scratch to most of the
> latest packages for the RaQ2. A question was raised by some other
> memebers of the Linux from Scratch group, that frankly I didn't have the
> answers for. I appreciate your feedback on these questions.
>
> 1 - Will the build method I have currently work with any MIPS processor
> based machine, with the exception of the bootloader?

The bulk of it would be largely the same -- however there would be a
difference in that endianness, ABIs and ISAs have to be considered.

e.g.
Cobalt Servers are Little Endian running RM523[01] CPUs (MIPS IV ISA).
All (MIPS-based) SGI machines are Big Endian, mainly with either MIPS
III or MIPS IV class CPUs.

Therefore you use mips-unknown-linux-gnu as the HOST on SGI boxes, and
mipsel-unknown-linux-gnu on Cobalts.  (Some even use
mips64-unknown-linux-gnu)

  > 2 - Is there a bootloader for MIPS that will work on every machine, or
> is different for every MIPS based machine's firmware? If so any examples
> out there how to implement?

Okay, a lot of MIPS machines implement the ARCs firmware, but still
there's a big variety of machines there -- so making one bootloader
support them all would be an outright nightmare.  Having said that,
there are several bootloaders that do get used across multiple machines.
  Some that come to mind:

- CoLo (the Cobalt Loader) for Cobalt servers
- ARCBoot for SGI machines
- U-Boot
- YAMON

and there are likely many more.  They've all got their own differences
-- just to give you an idea, have a look at my copy of the Gentoo/MIPS
handbook[2] -- specifically the bootloader section[3].  This version
covers setting up both Cobalt servers and SGI machines with Gentoo
Linux.  As you can see, there's a big difference between the machines.

Anyway, I hope that's answered some of your questions. :-)
--
+-------------------------------------------------------------+
| Stuart Longland -oOo- http://stuartl.longlandclan.hopto.org |
| Atomic Linux Project     -oOo-    http://atomicl.berlios.de |
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - |
| I haven't lost my mind - it's backed up on a tape somewhere |
+-------------------------------------------------------------+
Footnotes:
1. Note that the IP12 and it's R4k cousin, the IP20 are currently
unsupported in Linux at this time -- although people are working on that :-)
2. Got the clipboard applet ready?  This is a long one:
<http://www.longlandclan.hopto.org/~stuartl/gentoo/docs/index.php/gentoo-doc/en/handbook/handbook-mips.xml>
3. Configuring the Bootloader:
<http://www.longlandclan.hopto.org/~stuartl/gentoo/docs/index.php/gentoo-doc/en/handbook/handbook-mips.xml?part=1&chap=10>
... and yes, eventually this will be put on the main Gentoo site...
pending bug #81072: <http://bugs.gentoo.org/show_bug.cgi?id=81072>

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Linux from scratch

[Alexandru Juncu]

Hello!

I am not a professional kernel developer but I do like learning how
things work..especially operating systems like linux. I know the basis
stuff  about the linux kernel (enough to write a very simple kernel
module).  But I wanted to learn how things like a simple scheduler or
a memory manager would work.

Only reading the current kernel code is sometimes difficult because
all the layers of abstraction implemented in order to make Linux code
scale.  So I was thinking taking a much much older version of the
kernel and starting to analyze it. Something like...v0.01. Seems like
I'm on a good track since sched.c in v0.01 has 250 lines while shed.h
in the current kernel has 1200 :P.

But I couldn't get v0.01 to compile and I've search the Internet and
found that it needs a _lot_ of hacking to get it to work. So I moved
to try 1.0 which seems to have all of the basic features implemented
yet simple enough  to understand. But I am still  having trouble
compiling (having trouble with header files...). Although I could just
read the code and try to figure out what it does, I would like to be
able to modify it and compile and run it.

In order to avoid useless trial and error, I wanted to ask other
people that maybe did this: What is the oldest kernel version that can
be compiled on a current system and then pun on a virtual machine like
qemu-kvm or vmware?

On a side note, I did look into the "Linux from scratch" documentation
project, but that seems to tell you how to build a distribution, not a
kernel.

Thank you.

Linux from scratch

[Silviu Popescu]

On Tue, Apr 9, 2013 at 12:49 PM, Alexandru Juncu <alexj@rosedu.org> wrote:
> Hello!
>
> I am not a professional kernel developer but I do like learning how
> things work..especially operating systems like linux. I know the basis
> stuff  about the linux kernel (enough to write a very simple kernel
> module).  But I wanted to learn how things like a simple scheduler or
> a memory manager would work.
>
> Only reading the current kernel code is sometimes difficult because
> all the layers of abstraction implemented in order to make Linux code
> scale.  So I was thinking taking a much much older version of the
> kernel and starting to analyze it. Something like...v0.01. Seems like
> I'm on a good track since sched.c in v0.01 has 250 lines while shed.h
> in the current kernel has 1200 :P.
>
> But I couldn't get v0.01 to compile and I've search the Internet and
> found that it needs a _lot_ of hacking to get it to work. So I moved
> to try 1.0 which seems to have all of the basic features implemented
> yet simple enough  to understand. But I am still  having trouble
> compiling (having trouble with header files...). Although I could just
> read the code and try to figure out what it does, I would like to be
> able to modify it and compile and run it.
>
> In order to avoid useless trial and error, I wanted to ask other
> people that maybe did this: What is the oldest kernel version that can
> be compiled on a current system and then pun on a virtual machine like
> qemu-kvm or vmware?
>
> On a side note, I did look into the "Linux from scratch" documentation
> project, but that seems to tell you how to build a distribution, not a
> kernel.

I remember someone on kernel-newbies trying to do the same thing some
while ago[1].
Although the thread does not provide the solution it highlights some
of the obstacles you might face.
I also found a small blog post[2] about this. But the article is from
2007, and you're going for something way older than 2.4 so probably a
plethora of errors are coming your way.
Hope this helps and good luck.

[1] http://thread.gmane.org/gmane.linux.kernel.kernelnewbies/42878/focus=42884
[2] https://divyad.wordpress.com/2007/04/28/compiling-older-linux-kernels-preparations/

--
Silviu Popescu

Linux from scratch

[Mulyadi Santosa]

On Tue, Apr 9, 2013 at 4:49 PM, Alexandru Juncu <alexj@rosedu.org> wrote:
> In order to avoid useless trial and error, I wanted to ask other
> people that maybe did this: What is the oldest kernel version that can
> be compiled on a current system and then pun on a virtual machine like
> qemu-kvm or vmware?

try to check this out:
http://draconux.free.fr/os_dev/linux0.01.html

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

Linux from scratch

[Alexandru Juncu]

On 9 April 2013 14:32, Mulyadi Santosa <mulyadi.santosa@gmail.com> wrote:
> On Tue, Apr 9, 2013 at 4:49 PM, Alexandru Juncu <alexj@rosedu.org> wrote:
>> In order to avoid useless trial and error, I wanted to ask other
>> people that maybe did this: What is the oldest kernel version that can
>> be compiled on a current system and then pun on a virtual machine like
>> qemu-kvm or vmware?
>
> try to check this out:
> http://draconux.free.fr/os_dev/linux0.01.html

That's the site that made me think of trying 1.0 :P

Linux from scratch

[Mulyadi Santosa]

On Tue, Apr 9, 2013 at 7:18 PM, Alexandru Juncu <alexj@rosedu.org> wrote:
> On 9 April 2013 14:32, Mulyadi Santosa <mulyadi.santosa@gmail.com> wrote:
>> On Tue, Apr 9, 2013 at 4:49 PM, Alexandru Juncu <alexj@rosedu.org> wrote:
>>> In order to avoid useless trial and error, I wanted to ask other
>>> people that maybe did this: What is the oldest kernel version that can
>>> be compiled on a current system and then pun on a virtual machine like
>>> qemu-kvm or vmware?
>>
>> try to check this out:
>> http://draconux.free.fr/os_dev/linux0.01.html
>
> That's the site that made me think of trying 1.0 :P

Well, that's up to you, but I think that site is a good starting
point. You need something really simply but yet able to run
applications, no?

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

Linux from scratch

[Mulyadi Santosa]

On Wed, Apr 10, 2013 at 8:01 PM, Pietro Paolini <pulsarpietro@aol.com> wrote:
> Did you achieve in compile and run the 1.0 Linux kernel on your system ? I am really curios !
> Best Regards
> Pietro .
>
>
>
>

I haven't tested that by myself. IIRC I only tried to run the provided
disk image inside Qemu, but that's all.

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

Linux from scratch

[Alexandru Juncu]

On 11 April 2013 09:34, Mulyadi Santosa <mulyadi.santosa@gmail.com> wrote:
> On Wed, Apr 10, 2013 at 8:01 PM, Pietro Paolini <pulsarpietro@aol.com> wrote:
>> Did you achieve in compile and run the 1.0 Linux kernel on your system ? I am really curios !
>> Best Regards
>> Pietro .
>>
>>
>>
>>
>
> I haven't tested that by myself. IIRC I only tried to run the provided
> disk image inside Qemu, but that's all.

With the 1.0 source I tried moving around header files. It seems that
it needs some files that are not provided. I was assuming they were
glibc libraries so I tried to get the glibc version from that date. No
success.

I always thought that all files needed for the kernel to compile were
just in the kernel sources. I don't know if that is true for that
version or not or I am missing something.

With the 0.01 DrAcOnUx' s remastered source. It didn't compile because
some assembly errors in a file.

Linux from scratch

[Robert P. J. Day]

On Tue, 9 Apr 2013, Alexandru Juncu wrote:

> Hello!
>
> I am not a professional kernel developer but I do like learning how
> things work..especially operating systems like linux. I know the
> basis stuff about the linux kernel (enough to write a very simple
> kernel module).  But I wanted to learn how things like a simple
> scheduler or a memory manager would work.
>
> Only reading the current kernel code is sometimes difficult because
> all the layers of abstraction implemented in order to make Linux
> code scale.  So I was thinking taking a much much older version of
> the kernel and starting to analyze it. Something like...v0.01. Seems
> like I'm on a good track since sched.c in v0.01 has 250 lines while
> shed.h in the current kernel has 1200 :P.

... snip ...

  please don't. mucking around with v0.01 of linux might be
entertaining from a historical perspective but it won't have much
value in making you more hireable. :-)

  just pick a specific topic somewhere in the kernel and dig into it.
and make sure you learn git so you can use "git log" to follow along
so you can see the ongoing development as well.

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================