HighDots.NET Computer Hardware Forums  

Guessing the CHS of a block device.

Storage systems Storage system issues, both hardware and software (comp.arch.storage)


Discuss Guessing the CHS of a block device. in the Storage systems forum.



Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old   
Seongsu Lee
 
Posts: n/a

Default Guessing the CHS of a block device. - 05-05-2007 , 02:05 PM






Hi,

Is there any way to detect the CHS information of a block device
by only a software in Linux? I think the analysis of elapse time of
reading a block which has various distance of each another.

Any comments or similar tries will be helpful. Thank you in advance.


Reply With Quote
  #2  
Old   
Anton Rang
 
Posts: n/a

Default Re: Guessing the CHS of a block device. - 05-15-2007 , 11:45 AM






Seongsu Lee <senux (AT) senux (DOT) com> writes:
Quote:
Is there any way to detect the CHS information of a block device
by only a software in Linux? I think the analysis of elapse time of
reading a block which has various distance of each another.
You could try this, but be aware that:

(a) Track-to-track seek times are smaller than rotational latency.
If you can't figure out how to deal with rotational latency,
you will have to do a very large number of reads to extract
any statistically significant measurement of what causes a seek.

(b) There's random variation in the disk introduced by such things
as temperature compensation. Again this means you'll need an
awful lot of sector reads to learn anything.

(c) Head switch times are too small to measure reliably.

(d) The number of sectors per track varies from point to point on
the drive.

What are you trying to figure out? This doesn't seem a useful thing
to do.

Anton


Reply With Quote
  #3  
Old   
Folkert Rienstra
 
Posts: n/a

Default Re: Guessing the CHS of a block device. - 05-15-2007 , 05:52 PM



Hey, is that you again, babblebot?

"Anton Rang" <rang (AT) visi (DOT) com> wrote

Quote:
Seongsu Lee <senux (AT) senux (DOT) com> writes:
Is there any way to detect the CHS information of a block device
by only a software in Linux? I think the analysis of elapse time of
reading a block which has various distance of each another.

You could try this, but be aware that:

(a) Track-to-track seek times are smaller than rotational latency.
If you can't figure out how to deal with rotational latency,
you will have to do a very large number of reads to extract
any statistically significant measurement of what causes a seek.
Uhuh. And this is helpful how exactly.
There are no seeks in sequential reading.

Quote:
(b) There's random variation in the disk introduced by such things
as temperature compensation. Again this means you'll need an
awful lot of sector reads to learn anything.
Learn what exactly.

Quote:
(c) Head switch times are too small to measure reliably.
Uhuh. And how does that differ from track (cylinder) switch times.

Like the babblebot you are providing problems to a solution, a solution that you don't even bother to describe.

And this has what to do with CHS, exactly?

Quote:
(d) The number of sectors per track varies from point to point on
the drive.
Gee, now where did you learn that.

Quote:
What are you trying to figure out? This doesn't seem a useful thing
to do.
Babblebot revisited.

Quote:
Anton

Reply With Quote
  #4  
Old   
Bill Todd
 
Posts: n/a

Default Re: Guessing the CHS of a block device. - 05-15-2007 , 07:39 PM



Folkert Rienstra wrote:
Quote:
Hey, is that you again, babblebot?
Shut up, Folkert. The S/N ratio in c.a.s. has been fairly decent
lately, until you crawled back out from under your rock.

Please crawl back in again.

- bill


Reply With Quote
  #5  
Old   
Buddy
 
Posts: n/a

Default Re: Guessing the CHS of a block device. - 05-16-2007 , 11:11 AM



"Bill Todd" <billtodd (AT) metrocast (DOT) net> wrote

Quote:
Folkert Rienstra wrote:
Hey, is that you again, babblebot?

Shut up, Folkert.
And you are?

Quote:
The S/N ratio in c.a.s. has been fairly decent lately,
No wonder, when no one in your group was actually able enough to
offer a solution to the OP. No one with even a glimpse of a clue.

Maybe you shut them up too?

Quote:
until you crawled back out from under your rock.

Please crawl back in again.

- bill

Reply With Quote
  #6  
Old   
Bill Todd
 
Posts: n/a

Default Re: Guessing the CHS of a block device. - 05-17-2007 , 01:50 AM



Buddy wrote:
Quote:
"Bill Todd" <billtodd (AT) metrocast (DOT) net> wrote

Folkert Rienstra wrote:
Hey, is that you again, babblebot?

Shut up, Folkert.

And you are?
Someone with a low tolerance for loud-mouthed morons.

Quote:
The S/N ratio in c.a.s. has been fairly decent lately,

No wonder, when no one in your group was actually able enough to
offer a solution to the OP. No one with even a glimpse of a clue.
I addressed his apparent confusion about CHS nearly two weeks ago.
Perhaps you were snoozing and missed it. In any event, since you appear
to have nothing substantive to contribute yourself...

- bill


Reply With Quote
Reply




Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off



Powered by vBulletin Version 3.5.3
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.