[Elphel-support] CFAST cards with SATA adapter compatible

[Sebastian Pichelhofer]

Thanks for the details, but CFAST is a completely new standard that
has little in common with CF cards and also requires totally different
adapters.

Regarding the UDMA work around hints: Could you help me collect all
information together we currently have about it (info from axis
developer, etc.) so I can create a new wiki page describing the task
and then approach some people.

Regards Sebastian

On Sat, Feb 4, 2012 at 20:28, Andrey Filippov
<support-list at support.elphel.com> wrote:
> Sebastian,
>
> I just replied Carlos and wrote that the only problem with SATA devices was
> with the old  SSD made actually from the CF cards. Adapter is transparent,
> so if the CF card does not work in the camera directly, it will not work
> with the adapter.  For slow applications it is possible to disable DMA in
> the camera (needs adding the lying card to the blacklist and recompiling the
> software).
>
> Devices support some of 3 modes:
>
> 1) PIO (slow and loads CPU a lot)
> 2) DMA - fast
> 3) UDMA - even faster
> Most CF cards support only 1 and 3 and respond as if they support 2 also
> ETRAX processor has a bug in implementation of the UDMA, so UDMA is
> disabled, that means that in the camera we only have 1 and 2. When the
> camera detects the disk, it loads the device capabilities (1,2,3), and
> selects the fastest it can support - 2. But here the lie of the CF card
> controller comes to the light - and the camera fails to communicate with the
> disk. There is a black list of those untruthful cards in the driver, we
> already added some cards there -
> http://elphel.cvs.sourceforge.net/viewvc/elphel/elphel353-8.0/os/linux-2.6-tag--devboard-R2_10-4/drivers/ide/ide-dma.c?view=markup
>
>  Axis engineers said that it is possible to mitigate that bug and gave some
> hints how to do that, but we never worked on it ourselves and it is probably
> not too easy - otherwise Axis people would do it themselves. But if anybody
> with the driver development skills would volunteer - we would definitely
> love that and support such project.
>
> Andrey
>
> On Sat, Feb 4, 2012 at 11:53 AM, Sebastian Pichelhofer
> <sebastian.pichelhofer at gmail.com> wrote:
>>
>> Do you think that http://en.wikipedia.org/wiki/CFast#CFast CFast Cards
>> could work with this adapter:
>>
>> http://www.amazon.de/exec/obidos/ASIN/b003r4ifmg/geizhals1-21/ref=nosim?m=A3JWKAKR8XB7XF
>> connected to the Elphel camera over SATA.
>>
>> To my understanding the card itself acts like a drive and needs no
>> controller chip betweencard and camera that could lead to running into
>> the UDMA issues again. But the card itself might use UDMA... ;)
>> Any educated guesses?
>>
>> Regards Sebastian
>>
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>
>