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Groups > comp.os.linux.hardware > #2601

Re: Bad Hitachi disk.... how so from a pic?

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Aragorn a écrit :
> On Monday 08 December 2014 10:26, Richard Kettlewell conveyed the 
> following to comp.os.linux.hardware...
> 
>> Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> writes:
>>> Aragorn a écrit :
>>>> In the event of a machine with an ATA hard disk, almost everything
>>>> on account of disk I/O is handled by the CPU on the mainboard, while
>>>> in the event of a SCSI controller, the operating system offloads a
>>>> great deal of those low- level tasks onto the controller itself,
>>>> which (of course) has its own dedicated (and typically specialized)
>>>> processor(s).
>>>
>>> Is this still true with modern AHCI SATA host controllers ?  What are
>>> these low-level tasks that are performed by a SCSI host controller
>>> but not by a SATA host controller ?
>>
>> AFAIK it hasn't been true since the 1980s.  The "integrated" in
>> Integrated Drive Electronics (i.e. the original name for PATA) refers
>> to the integration of the controller into the drive.
> 
> No, not the controller.  That which is integrated into the drive are the 
> most elementary drive electronics - voltage regulators and such - which 
> is not the same thing as an actual disk controller.

I think you're misinformed. What you describe looks like the simple
electronics of a floppy drive, not of an ATA or SCSI disk drive. An
integrated controller is much more elaborated, with a specialized
processor, RAM... and processes high level commands.

> Command queuing for instance is a controller task, and when it comes to 
> IDE disks, the kernel will take care of that.  When it comes to SCSI or 
> SAS, the controller card does all of that, leaving the mainboard CPU 
> free to do other things.

Command queuing is performed by the integrated controller. ATA has
commands such as READ DMA QUEUED (queued read of a sector range using
DMA for transfer) which are sent to and executed by the disk itself.

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Bad Hitachi disk.... how so from a pic? Jax <remove.bear.bottoms1@gmail.com> - 2014-12-06 14:44 +0000
  Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-06 09:44 -0600
    Re: Bad Hitachi disk.... how so from a pic? notbob <notbob@nothome.com> - 2014-12-06 19:37 +0000
      Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-06 14:54 -0600
      Re: Bad Hitachi disk.... how so from a pic? Jax <remove.bear.bottoms1@gmail.com> - 2014-12-06 22:50 +0000
        Re: Bad Hitachi disk.... how so from a pic? notbob <notbob@nothome.com> - 2014-12-06 23:13 +0000
      Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-07 04:57 -0600
        Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-07 16:52 +0100
          Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-07 09:59 -0600
            Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-07 17:10 +0100
              Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-07 10:48 -0600
                Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-07 18:37 +0100
                Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-07 12:28 -0600
                Re: Bad Hitachi disk.... how so from a pic? Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2014-12-07 21:46 +0100
                Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-07 22:27 +0100
                Re: Bad Hitachi disk.... how so from a pic? Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2014-12-08 00:36 +0100
                Re: Bad Hitachi disk.... how so from a pic? Richard Kettlewell <rjk@greenend.org.uk> - 2014-12-08 09:26 +0000
                Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-08 11:31 +0100
                Re: Bad Hitachi disk.... how so from a pic? Richard Kettlewell <rjk@greenend.org.uk> - 2014-12-08 10:53 +0000
                Re: Bad Hitachi disk.... how so from a pic? Aragorn <thorongil@telenet.be.invalid> - 2014-12-08 17:48 +0100
                Re: Bad Hitachi disk.... how so from a pic? Richard Kettlewell <rjk@greenend.org.uk> - 2014-12-08 17:28 +0000
                Re: Bad Hitachi disk.... how so from a pic? Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2014-12-08 08:43 -0600
                Re: Bad Hitachi disk.... how so from a pic? Pascal Hambourg <boite-a-spam@plouf.fr.eu.org> - 2014-12-09 11:02 +0100
                Re: Bad Hitachi disk.... how so from a pic? scott@alfter.diespammersdie.us (Scott Alfter) - 2014-12-09 23:35 +0000
                Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-09 17:43 -0600
                Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-09 17:54 -0600
                Re: Bad Hitachi disk.... how so from a pic? scott@alfter.diespammersdie.us (Scott Alfter) - 2014-12-10 20:22 +0000
                Re: Bad Hitachi disk.... how so from a pic? scott@alfter.diespammersdie.us (Scott Alfter) - 2014-12-10 20:27 +0000
                Re: Bad Hitachi disk.... how so from a pic? philo  <philo@privacy.net> - 2014-12-10 16:40 -0600
                Re: Bad Hitachi disk.... how so from a pic? Thomas Richter <thor@math.tu-berlin.de> - 2014-12-10 11:06 +0100
  Re: Bad Hitachi disk.... how so from a pic? Baho Utot <baho-utot@invalid.com> - 2014-12-06 13:39 -0500
    Re: Bad Hitachi disk.... how so from a pic? Jax <remove.bear.bottoms1@gmail.com> - 2014-12-06 22:51 +0000
  Re: Bad Hitachi disk.... how so from a pic? Johnny <johnny@invalid.net> - 2014-12-06 13:02 -0600
  Re: Bad Hitachi disk.... how so from a pic? Keith Keller <kkeller-usenet@wombat.san-francisco.ca.us> - 2014-12-06 16:04 -0800

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