Which disk is which

Kevin D. Kinsey, DaleCo, S.P. kdk at daleco.biz
Mon Aug 30 16:22:57 UTC 2004


Hi, John ...

As you cc'ed doc@, I'm sending your original mail to them
also, so they'll have some background.  Comments inline.

John Summerfield wrote:

>I've booted a 5.2.1 miniinstall CD and got to the point where I choose which 
>disk to install onto.
>
>My choices are
>ad0
>da0
>
>Great. How do I know which disk is which? _I_ could work it out if the panel 
>displayed information such as
>Brand
>Capacity
>
>  
>

Read the *text* in the handbook.  As an example, the following
appears on the page that you linked in your recent crosspost to doc@:

    "Consider what would happen if you had two IDE hard disks, one
    as the master on the first IDE controller, and one as the master
    on the second IDE controller. If FreeBSD numbered these as it
    found them, as ad0 and ad1 then everything would work.

    But if you then added a third disk, as the slave device on the first
    IDE controller, it would now be ad1, and the previous ad1 would " ....

<>This goes on for another 3-4 paragraphs; it is a discussion of why FreeBSD
has basically "hardcoded" disk drive names/numbers into the kernel, (e.g.,
why IDE primary master will always be ad0, why secondary slave will always
be ad3, etc). 

Then again, just above figure 2-16 (which is the same as figure 2-20
but without an "X" in the checkbox):

Figure 2-16 
<http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/install-steps.html#SYSINSTALL-FDISK-DRIVE1> 
shows an example from a system with two IDE disks.
They have been called ad0 and ad2.


Based on reading these sections/statements of the manual, it would seem
somewhat obvious that ad0 is the primary master IDE hard disk.  It is
hard, then, at least for me, to see this as a fault of the documentation.

It was also unfortunate that no one on questions@ mentioned the USB
drive angle until late in the conversation, perhaps....


>Note: DOS names would be worse than useless because I don't use DOS, and the 
>BIOS doesn't detect all my drives.
>  
>

It doesn't have to, because the kernel ignores the BIOS drive
information anyway ....

>The website doesn't help.
>
>  
>

That seems to be debatable, as I noted above, maybe?  The information
was there; I would grant that the search engine(s) may not have found
it for you.  I've found FreeBSD works better for me if I take the time to
read the whole chapter or book rather than the "quick skimming" habit
that the sheer volume of information on the Internet has forced me into....

>I'm not on any list. Please respond by
>a) Fixing the web page
>b) Mailing me the necessary info (eg the fixed page when it's done) in case I 
>can't discover by other means which is which.
>  
>

I'm not a docteam member, although I read the list and think
I have one sentence in the handbook (so that may make me
one "technically speaking" --- it's a somewhat loose assocation,
apart from those members who are actually committers).
 
I certainly don't represent the FreeBSD organization as a whole
--- I'm simply a user, like so many others.  I apologize if I seem
curt, it is certainly not my intention, and I'm not writing to
"flame" or "offend" you or anyone else.

Your suggestion "if the panel displayed information such as Brand
(&) Capacity" is certainly valid from an end-user standpoint.  Some
operating systems might well do that; that's a totally different subject,
though.  And that isn't about the docs, either, it's about the installation
program, which is a years-old hydra that no Heracles has yet stepped
up to behead....

Kevin Kinsey
DaleCo, S.P.



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