partition structure/layout
annalissa
I have recently rewad in some tutorials that structure/layout of
a linux partition is as shown here :-
http://i529.photobucket.com/albums/dd339/aarklon/partition.png
now is this same layout/structure used for both primary and logical
partitions ?
Wanna-Be Sys Admin
I can't understand exactly what you're asking?
--
Not really a wanna-be, but I don't know everything.
annalissa
> annalissa wrote:
>
>> Hi all,
>>
>> I have recently rewad in some tutorials that structure/layout
>> of
>> a linux partition is as shown here :-
>>
>> http://i529.photobucket.com/albums/dd339/aarklon/partition.png
>>
>> now is this same layout/structure used for both primary and logical
>> partitions ?
>
> I can't understand exactly what you're asking?
i mean this
see:-
http://www.csie.ntu.edu.tw/~pangfeng/System%20Programming/Lecture_Note_2.htm
philo
Ok
I see why you've asked the question
and it looks like those "lecture notes" are wrong
In them it states
(quote):
"In fact a symbolic link is very much like the "shortcut" in Windows.
However, in Windows only file can have shortcut, not directory."
(end quote)
Don't know where they came up with that one as in Windows one can of
course have shortcuts to folders.
maybe you need to find a better tutorial
Aragorn
identifying as annalissa wrote...
Yes, they have the same layout. The only difference between a primary
and logical partition is that a primary partition has its partition
table entries - i.e. the beginning and end of the partition - listed in
the partition table of the master boot record of the hard disk it sits
on, while a logical partition has its partition table entries listed in
an extended partition container, which itself is a (special kind of)
primary partition.
The Linux kernel doesn't care about whether a partition is either
primary or logical, or whethr it's an LVM logical volume for that
matter. (Note: LVM "Logical Volume Management") is an abstraction
layer on top of the existing partitioning layer.)
See, the distinction between primary partitions and logical partitions
in an extended partition container is a construct of the legacy real
mode[1] BIOS and of DOS, because originally, the IBM PC and all
derivative machines did not have (or support) hard disks, and DOS did
not support them either. Then, with the IBM XT ("eXtended Technology")
and as of DOS 3.00, support for hard disks was added to both the legacy
BIOS and to DOS, but the original hard disks for such machines were
rather small, e.g. 5 MB, 10 MB, 20 MB, 30 MB. The BIOS supported four
primary partitions, of which one had to be marked "active", because the
bootloader was a BIOS routine that would select the operating system to
boot from one of the four possible partitions, and the "active" flag
was the indicator to the BIOS which partition's bootsector to load into
memory and pass control of the machine onto. The "active" primary
partition was thus the one holding the operating system selected to
boot at machine power-up, while the other primary partitions could
eventually hold another operating system, and selecting which one to
boot was then only a matter of marking the proper partition
as "active".
It was only later, with the introduction of the IBM AT ("Advanced
Technology") and hard disks beyond 32 MB in capacity that the support
for logical partitions in an extended partition container was added,
because DOS could only handle a partition size of 32 MB - this would
later be partly remedied in DOS 4.0 via a special trick, and would more
appropriately be resolved in DOS 5.0. Logical partitions in the
extended partition container cannot be marked "active", but the
construct allowed DOS to use a primary partition - i.e. only
the "active" one, as it could not access the other primary partitions
on the same disk - plus an additional number of logical partitions in
the extended partition container.
Windows still abides by the legacy partitioning scheme and the concept
of an "active" primary partition, in that Windows still makes use of
the legacy BIOS bootloader code which reads the partition table of the
first hard disk in the system - i.e. the hard disk marked in the BIOS
as "bootable" - and then, via this partition table, locates
the "active" primary partition and loads its bootsector (or "boot
block", if you will) into memory, and then passes all control over the
machine onto that piece of code, which is then the Windows NT
bootloader. At that stage, the x86 processor[2] is still in real mode,
and this is how real mode operating systems like DOS worked, i.e. by
loading a piece of code into memory and passing all control of the
machine onto that segment of code. The Windows bootloader program will
then load another piece of code into memory, which would then be the
bootstrap code of the Windows NT kernel, and it is only this bootstrap
code that sets up the pagetables and switches the processor into
protected mode.
GNU/Linux on the other hand works quite differently. Although the real
mode BIOS mechanism of loading an "active" primary partition's
bootsector into memory can still be used - e.g. in the event that the
GNU/Linux bootloader would reside inside a partition's bootsector, as
opposed to the normal and recommended way of setting up a GNU/Linux
system by having its bootloader reside in the master boot record of the
hard disk marked in the BIOS set-up program as "bootable", hereby
overwriting the legacy BIOS bootloader code which looks for an "active"
primary partition. The GNU/Linux bootloader - itself also still a real
mode program - will then directly load a kernel image into memory
without looking at the partition type. This kernel image consists of
real mode bootstrapping code and a compressed image of a protected mode
kernel, and the real mode bootstrapping code then sets up the
pagetables, switches the processor into protected mode and decompresses
the actual protected mode kernel.
And as such, the legacy principles which were only invented so as to
allow a real mode operating sytem such as DOS or CP/M to boot on an x86
processor do not apply to GNU/Linux, nor to most other UNIX systems I
know of - Minix and Microsoft's or SCO's Xenix would be exceptions
since they were written for the 8086 architecture.
[1] "Real mode" is the 8086-compatible mode of all x86 processors as
of the 80286 on. All x86 processors are by design in real mode
at power-up for DOS-compatibility, and as such, the legacy BIOS
was still written as real mode code as well. XT and AT were only
extensions to that old 16-bit real mode BIOS code. There are
however protected mode BIOS versions[3] which already set up
protected mode on the boot processor from within the BIOS - e.g.
EFI, CoreBoot (formerly known as LinuxBIOS) - but these require a
special version of the GRUB or LILO bootloaders[4], and a modified
kernel image (without real mode bootstrapping code). However, at
machine power-up, the processor is still in real mode by design,
so the BIOS must first initialize protected mode.
[2] During boot-up, only one processor is active - i.e. one CPU core
on multi-core processor chips - and it is the kernel which, once
protected mode has been entered, initializes the other processors
and sets up the symmetric multiprocessing or NUMA[5].
[3] EFI ("Extensible Firmware Interface") and CoreBoot also allow for
a different partitioning system, where you can have up to 128
primary partitions per hard disk, and where the special protected
mode versions of LILO or GRUB actually become extensions to the
BIOS. However, due to limitations in the Linux kernel, Linux can
only handle 63 partitions in total on IDE disks accessed via the
older ATA code or 15 partitions on SAS, SCSI, SATA and USB disks,
and on IDE disks accessed via the newer /libata/ code. Among the
computers which use an EFI BIOS are the Intel-based Apples and
all machines with an Intel Itanium processor. Some motherboard
manufacturers also support EFI or CoreBoot - Tyan used to support
it but seems to have dropped that support again a few years ago -
but only very few GNU/Linux distributions are actually built to be
used with such firmware. Most are simply built for systems with a
legacy BIOS. (Remember, you need a different version of either
LILO or GRUB, and you need a different Linux kernel image.)
[4] Non-x86 machines like the IBM PPC, Sun (Ultra)SPARC, SGI MIPS,
Hewlett-Packard Alpha and PA-RISC, Intel Itanium et al already
use such special versions of LILO or GRUB, since those processor
architectures do not have a real mode. (Itanium does, but only
via an x86-32 emulation mode, which must be explictly selected
at boot time and/or enabled in the EFI firmware.)
[5] NUMA stands for "Non-Uniform Memory Access" and is (on x86) the
kind of multiprocessing found on AMD's 64-bit processors and on
the newer Intel i7 systems, where you have multiple processor
sockets with each socket having its own memory controller. As
such, each socket - which houses a single- or multi-core processor
chip - has its own local memory, while still being able to see
all of the installed memory via access through the other processor
sockets. This principle avoids the bottleneck of having a single
memory controller for all processor sockets on the motherboard.
--
*Aragorn*
(registered GNU/Linux user #223157)
Sidney Lambe
wrote:
Wow! That's what you call an _answer_!
Sid
Ryan McCoskrie
> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
> wrote:
> [snip long discription of low level information]
>
> Wow! That's what you call an _answer_!
>
> Sid
Are you the same Sid we usually get? You just said something nice about
Aragorn!
--
Quote of the login:
An Ada exception is when a routine gets in trouble and says 'Beam me up,
Scotty'.
Sidney Lambe
> Sidney Lambe wrote:
>
>> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
>> wrote:
>> [snip long discription of low level information]
>>
>> Wow! That's what you call an _answer_!
>>
>> Sid
>
> Are you the same Sid we usually get? You just said something nice about
> Aragorn!
I say nice things about people when they do nice things and bad
things about them when they do bad things.
That is, if they aren't among the 99.999999999999% of the
population whom I simply ignore as individuals, just keeping a
casual eye on their collective behavior.
Make sense to you?
Sid
Peter Köhlmann
> On comp.os.linux.setup, Ryan McCoskrie <ryan.mc...@invalid.invalid>
> wrote:
>> Sidney Lambe wrote:
>>
>>> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
>>> wrote:
>>> [snip long discription of low level information]
>>>
>>> Wow! That's what you call an _answer_!
>>>
>>> Sid
>>
>> Are you the same Sid we usually get? You just said something nice about
>> Aragorn!
>
> I say nice things about people when they do nice things and bad
> things about them when they do bad things.
>
> That is, if they aren't among the 99.999999999999% of the
> population whom I simply ignore as individuals, just keeping a
> casual eye on their collective behavior.
>
> Make sense to you?
>
>
> Sid
No, Alan Connor, it does not. It simply serves to describe you as the
nutter you really are
And just forget about your nymshifting tricks. You are way to incompetent
to show up here as that phoney "Sidney Lambe"
--
I refuse to have a battle of wits with an unarmed person.
Wanna-Be Sys Admin
> Wow! That's what you call an _answer_!
Is this your first day on usenet? Learn how to snip, you moron! You
quota hundreds of lines of text to have a short 7 letter sentence?
philo
> Sidney Lambe wrote:
>
>> Wow! That's what you call an _answer_!
>
> Is this your first day on usenet? Learn how to snip, you moron! You
> quota hundreds of lines of text to have a short 7 letter sentence?
He is a well know troll
kill-filed by most here
Aragorn
identifying as Ryan McCoskrie wrote...
> Sidney Lambe wrote:
>
>> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
>> wrote:
>> [snip long discription of low level information]
>>
>> Wow! That's what you call an _answer_!
>>
>> Sid
>
> Are you the same Sid we usually get? You just said something nice
> about Aragorn!
Well, I am pleased that even Alan Connor/Sidney Lambe can appreciate my
technical verbosity, albeit that I too am surprised that he actually
does. :-)
Evergreen
wrote:
> On Monday 28 December 2009 09:52 in comp.os.linux.setup,
> somebody identifying as Ryan McCoskrie wrote...
>
>> Sidney Lambe wrote:
>>
>>> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
>>> wrote: [snip long discription of low level information]
>>>
>>> Wow! That's what you call an _answer_!
>>>
>>> Sid
>>
>> Are you the same Sid we usually get? You just said something
>> nice about Aragorn!
>
> Well, I am pleased that even Alan Connor/Sidney Lambe can
> appreciate my technical verbosity, albeit that I too am
> surprised that he actually does. :-)
>
But I am not surprised that you are gullible and foolish
enough to take the word of a stinking headcase troll
who refuses to identify himself and hides behind a
hundred fake names and spends his life harassing people
for allegedly hiding behind fake names and refusing
to identify themselves.
For those who don't know what we are talking about, that's
where Aragorn gets the idea that I'm someone called
"Alan Connor". I believe that the troll accuses me
of being a lot of other people too.
All or most of his aliases are in my killfile. Having
a functioning mind, I wouldn't believe a word he said
about anything. I cannot conceive of a person with
less credibility than he has.
I do hope that Aragorn doesn't stumble across any
of the UFO abduction websites. The consequences
would be dreadful for someone who believes anything
anyone publishes on the Internet.
He'd start wearing tinfoil sleeping hats and staying
indoors at night and calling the Police every time
he saw something in the sky he couldn't identify.
Sid
Evergreen
Unless I make a mistake like this one I only use it on those
forums and in conjuction with the signature below.
Note that my real name also appears in the email address.
On comp.os.linux.setup, Evergreen <sidne...@nospam.invalid> wrote:
> On comp.os.linux.setup, Aragorn <ara...@chatfactory.invalid>
> wrote:
[delete]
To all the losers who will use this an excuse to sling
juvenile abuse at me, just relaxe. You are in my killfile
and I won't even see it.
And I don't care what ignorant and stupid people think.
Sid
--
Sidney Lambe
Apprentice Magician
http://tinyurl.com/7vs9zb
usenet4444 (at) gmail (dot) com
Wanna-Be Sys Admin
I had him kf'ed myself, he just left for a while and I hoped he was
dead.
Wanna-Be Sys Admin
> But I am not surprised that you are gullible and foolish
> enough to take the word of a stinking headcase troll
> who refuses to identify himself and hides behind a
> hundred fake names and spends his life harassing people
> for allegedly hiding behind fake names and refusing
> to identify themselves.
>
> For those who don't know what we are talking about, that's
> where Aragorn gets the idea that I'm someone called
> "Alan Connor". I believe that the troll accuses me
> of being a lot of other people too.
But, you_are_ posting from different names and trolling regardless. It
was quiet from you for a while. Did you just get back out of prison
after your 3rd sex offense charge? Did you inform your neighbors? Are
you supposed to be online? Aren't you violating your parole? Your
wiccan super powers aren't going to convince anyone you're anything
that you aren't. Sadly, for you. Just act decent and no one will care
what name you use.
Wanna-Be Sys Admin
> All or most of his aliases are in my killfile.
Yeah, right, "all of them" _except_ the one and only user posting name
he's been using for _years_. There's a big hole in your story right
there. You replied to him above, and then say you have all of his
names kf'ed, even though everyone's only posting as their one, sole,
single name.
Wanna-Be Sys Admin
> "Evergreen" is my magickal name
oooh, scary...
Wanna-Be Sys Admin
> To all the losers who will use this an excuse to sling
> juvenile abuse at me, just relaxe. You are in my killfile
> and I won't even see it.
You know who will think poorly of you and post in response, before they
do it? Wow, you do have magic(k)al powers after all. So, you're
effectively kf'ed everyone, yet you reply to them? Gaping hole in your
story, yet again.
> And I don't care what ignorant and stupid people think.
I agree, no one cares what you think.
philo
> philo wrote:
>
>> Wanna-Be Sys Admin wrote:
>>> Sidney Lambe wrote:
>>>
>>>> Wow! That's what you call an _answer_!
>>> Is this your first day on usenet? Learn how to snip, you moron! You
>>> quota hundreds of lines of text to have a short 7 letter sentence?
>>
>>
>> He is a well know troll
>> kill-filed by most here
>
> I had him kf'ed myself, he just left for a while and I hoped he was
> dead.
he's brain dead
good enough