[ale] difference between android and linux ?

Jim Kinney jim.kinney at gmail.com
Fri Aug 12 18:14:17 EDT 2011


To simplify some of this excellent material:

The kernel, and ONLY the kernel, is Linux. The rest of the stuff on the
system, whether it's Ubuntu, Fedora, Android or other, is the system layer
of applications. Ubuntu, Fedora, Slackware, Suse, mint, etc are all related
and cab be classed as GNU/Linux environments. Linux kernel and GNU libraries
and other tools running the bulk of the rest with a ton of other OpenSource
code to glue it all together.

Android is NOT GNU/Linux. The kernel is Linux but the application stack is
all android. And rather different from the GNU stack most of use are
accustomed to.

So applications on Android won't run on GNU/Linux systems and GNU/Linux
applications also won't run on Android. Principle reason is the vastly
different set of libraries.


On Fri, Aug 12, 2011 at 5:59 PM, Michael B. Trausch <mike at trausch.us> wrote:

> On 08/12/2011 05:15 PM, Ron Frazier wrote:
> > Thanks for the info.  OK, the essence of what you're saying is, Android
> > is a variant of Linux and Ubuntu (and other similar) are variants of
> > Linux, but as a practical matter, they're not software compatible.
>
> Your confusion is understandable.  Our community often refers to whole
> systems as "Linux".  A lot of people in our community for years said
> that was a dandy term because it was unambiguous.  Some have argued for
> years that it is ambiguous because of the lack of understanding it
> yields, and today, when the Linux kernel is used in more places than
> most other operating system kernels, this ambiguity is coming to light.
>
> Neither Android nor Ubuntu are "Linux variants".  They are both systems
> which are built on top of the Linux kernel.  Furthermore, there are
> other, non-Android/Linux, non-GNU/Linux systems out there, albeit of
> quite limited popularity.
>
> What I have told people for years---and will continue to tell
> people!---is that a kernel alone does not an operating system make.
> Application software is designed to run on one or more "operating
> systems", and from the point of view of an application program, the
> operating system is a standard interface that the program can use to do
> its work.  Unfortunately, the very nature of that definition is that
> there are a lot of grey areas.
>
> Unfortunately, I can think of no single operating system that I can cite
> as a means to clarify that grey area.  Much like the US federal court's
> opinion of obscenity, "I know what [an operating system is] when I see it."
>
> To try to help (and with the realization that this may cause even more
> confusion): Gentoo, Slackware, Debian, Red Hat Enterprise Linux,
> Ubuntu---they are all the names of operating system distributions.  They
> all do things differently.  They all, however, serve much the same
> purpose, to drive our hardware and provide a platform for applications
> to run on top of.  Much the same can be said for Microsoft Windows 7,
> albeit for a much more limited selection of hardware and in some cases
> more applications (since it is a popular target for proprietary
> software, whereas most Linux systems are not, and nearly all free
> software that runs on Linux-based systems is capable of running on
> Windows in some way or another).
>
> Back in the days of Windows 9x, there was a lot of questions as to
> whether Windows 9x constituted an operating system or not.  I tell
> people that they _were_ operating systems.  They essentially used MS-DOS
> as a bootstrap, and attempted to provide a large degree of backwards
> compatibility that ultimately proved to be detrimental to the Windows 9x
> ecosystem.  The NT-based versions of Windows were (are) the answer to
> that problem, where DOS is no longer something that actually is executed
> on the system, but is instead fully emulated in a virtual machine (on
> 32-bit versions of Windows; no longer is that the case on 64-bit
> versions of Windows, though 64-bit versions of Linux can still run DOS
> programs :-)).
>
> In any event, an operating system is much more than the kernel; core
> libraries and system interfaces that are provided "on top of" the kernel
> can be considered to be part of the operating system.  From the point of
> view of applications (as well as users), an operating system provides a
> minimum set of libraries and application programs (/bin/sh, /bin/ls,
> etc.) with it.
>
> > So,
> > if I get an Android tablet, I would get apps from the Android
> > marketplace (if supported) and independent Android websites.  If I get a
> > Linux tablet, I would apps from it's repositories or independent Linux
> > websites.  The software from the one would not work on the other type of
> > platform unless the software specifically mentioned that it works on
> > Android or Linux respectively.
>
> It is possible to install Debian "on top of" Android, as well as other
> operating systems, such as Ubuntu.  However, doing this is an incredible
> task and requires a significant amount of understanding as to what it is
> that you're doing, and precisely why it works.  You must also be sure
> that you have a Linux kernel that is configured to sufficiently satisfy
> the requirements of both systems; for example, newer distributions that
> are now using systemd as an init dæmon are no longer able to work with
> kernel versions later than 2.6.39 (e.g., the very last 2.6 kernel),
> which you won't find as the basis of Android systems yet.
>
> > That brings up a couple of more questions.  Hypothetically, say I get an
> > ARM9 Android tablet with 512 MB RAM and a 500 MHz processor.  Is it
> > possible to reflash it to run either Android (as designed) or a variant
> > of GNU/Linux, and to switch back and forth between the two, so I can do
> > development and testing either way.  Also, I'm seeing designations of
> > several types of ARM processors, such as ARM v5, ARM 9, ARM v9, etc.  Do
> > these variations substantially affect the capabilities of the system and
> > is it something I need to be worried about.
>
> System requirements can be deceiving.  Nobody in their right mind would
> run a full Ubuntu stack on hardware that was originally designed to run
> Android, because it would be intolerably slow; Android as a platform
> defines a set of constraints that enable it to fit in a
> resource-constrained (rather, what we today call resource-constrained)
> systems.  Of course, back in the day of the 8088, our modern Android
> gadgets would be considered to possess an almost god-like power, but
> that's neither here nor there.  :-)
>
> That said, Android *has* been ported to run on x86/x86-64 hardware.  You
> can run Android on a PC just fine.  You can even dual boot a GNU/Linux
> system and Android if you so desire.  Given enough motivation, you can
> do just about anything that your heart desires.  You could even use
> Dalvik on top of Ubuntu if you really wanted to, though I cannot imagine
> a reason that anyone would.
>
> I would suggest that you do a lot of reading on what comprises a
> barebones functional GNU/Linux stack (ignore extras such as X!) and what
> comprises a barebones functional Android stack (which includes a fair
> bit more than a barebones functional GNU/Linux stack, in terms of
> functionality and defined programming interfaces).  Look at the
> platforms that they run on; the bootloader, the kernel, what starts up
> as PID 1, the libraries that are considered to be part of the base
> system, and so forth.  This will significantly increase your
> understanding of what the systems really are, and how they can be made
> to interoperate without a hypervisor (if truly desired).
>
> And yes, it would be possible (in theory) to "port" Android to run in a
> window on an X11 display.  That doesn't really make it "not an operating
> system", for various reasons.  One operating system can be made to run
> on top of another operating system, after all---especially when
> everything involved is either free software or open source, truly
> _anything_ is possible!
>
>        --- Mike
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-- 
-- 
James P. Kinney III

As long as the general population is passive, apathetic, diverted to
consumerism or hatred of the vulnerable, then the powerful can do as they
please, and those who survive will be left to contemplate the outcome.
- *2011 Noam Chomsky

http://heretothereideas.blogspot.com/
*
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