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Date:      Mon, 28 Dec 2009 15:14:16 +0100
From:      Polytropon <freebsd@edvax.de>
To:        Fbsd1 <fbsd1@a1poweruser.com>
Cc:        Jerry McAllister <jerrymc@msu.edu>, FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: re-write is this booting info correct?
Message-ID:  <20091228151416.07a2f22d.freebsd@edvax.de>
In-Reply-To: <4B38ACF9.2050705@a1poweruser.com>
References:  <4B296E66.6030405@a1poweruser.com> <20091217064959.e62bfdbb.freebsd@edvax.de> <20091217151140.GA40367@gizmo.acns.msu.edu> <4B38ACF9.2050705@a1poweruser.com>

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On Mon, 28 Dec 2009 21:04:57 +0800, Fbsd1 <fbsd1@a1poweruser.com> wrote:
> The Microsoft/Windows fdisk program is used to allocate partitions on 
> the hard drive. This program allocated two types of partitions “primary 
> dos partition” and “extended dos partition”.

Just a formal addition: "primary DOS partition" - DOS stands
for "Disk Operating System", it's an abbreviation. You're
stating this later on, but you should do it at its first
occurance.



> A single “primary dos partition” occupying all the space on the hard 
> drive would be assigned drive letter C.

The "drive letters" used seem to include the ":" as a part,
so it would be "C:" instead of plain "C".



> An alternate method is to allocate an “extended dos partition” and then 
> sub-divide it into logical dos drives lettered C, D, E, F.

I think the term is "logical volume inside an extended DOS
partition"; I'm not very familiar with their english names,
but that would correspond to the correct german name (found
in german versions of DOS); the term is "volume" or "drive".

I've got no english DOS documentation here, so I can't
check for the correct term.

German: "Primäre DOS-Partition" and "Logisches Laufwerk in
einer erweiterten DOS-Partition", and "Laufwerk" means
"drive", but I think I recall that DOS uses "volume" for
this...



> One of these 
> “primary dos partitions” or one of the logical dos drives in the 
> “extended dos partition” must be set as the active partition to boot 
> from.

I'm not sure you can actually boot from a logical volume
inside an extended DOS partition... as far as I remember,
booting can only take place from a primary DOS partition.




> FreeBSD’s fdisk program allocates disk space into slices. A FreeBSD 
> slice is the same thing as a Microsoft/Windows  “primary dos partition”. 
> FreeBSD has nothing akin to an “extended dos partition”.

It quite has - its slices (which are subdivided just as the
extended DOS partitions are, so its partitions are like - 
but not the same as - the logical volumes inside a DOS
extended partition).



> The 
> Microsoft/Windows partition and the FreeBSD slice is where the operating 
> system software is installed.

No. The software is installed on the partitions inside a
slice, or, to be more exact, in the file system that the
partition holds. There can be of course one partition
coviering the whole slice, so "partition(s)" would be
a valid term.



> The FreeBSD 
> ‘disk label’ program is used to sub-divide the slice into smaller chunks 
> called partitions. In a standard install of FreeBSD, these partitions 
> are the default directory names used by the operating system.

Not "are" - they _refer_ to them (or are refered to by
then), e. g. the default directory name / is the root
directory, but /dev/ad0s1a is the partition; /usr is the
directory for { UNIX system resources | user binaries and
libraries }, but /dev/ad0s1g is (maybe) the partition that
holds this data. In settings where one partition convers
the whole slice, there are no further mountpoints for the
divisions of functional parts of the system.



> The motherboard standard which was created in the days before windows 
> desktop were even though of yet and at which time Microsoft DOS (disk 
> operating system) was the only thing available.

Sure. :-)



> This hard drive 512-byte MBR is where all the limitations are. Do to 
> it’s size the MBR partition table is limited to 4 entries.

Due to its size...



> This means no 
> matter how large your hard drive is (20MG or 200GB) you can only 
> sub-divide it into a maximum 4 slices/partitions.

20MB. But I'd like to have a 20 machine gun hard disk, too. :-)



> The default MBR code written by the Microsoft/Windows fdisk program is 
> hard coded to boot the C drive. The FreeBSD fdisk program has option to 
> write a simple boot menu program to the MBR.

You could add that this program is called the "FreeBSD boot
manager", because that's its actual name.



Everything else seems to be correct to me, as well as
written in an appealing way, and technically understandable.



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...



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