Dieter wrote:
You could use their 7506-4LP card for this. However, I think
that this would be overkill and the price of the card is >
$200, and you would also need 4 short IDE cables
PATA cables must be in the range of 10-18 inches. Just one of
several reasons to prefer SATA.
You can always make your own. Or, have your local screw driver
shop make them for you.
There are also adapters that plug in directly (female plug) or can
be used with short extension cables
It is easy to find PATA cables 24 and even 36 inches long, and yes,
it is just a ribbon cable so you can easily make your own whatever
length you want.
BUT:
PATA isn't terminated, and is "designed" (cough) to work with cables
between 10 and 18 inches. If the cable is shorter than 10 inches or
longer than 18 inches then you are more likely to lose data.
That is interesting but:
1. Notebooks have much shorter cables, as short as 2 inches.
2. 2 inch long 40 Pin IDE cables are probably also available.
IIRC, if a transmission line is short enough, it doesn't need to be
terminated. Short enough is determined by data rate and rise time.
PATA doesn't have error detection & correction on everything so your
data is at risk. SATA does have error detection & correction on
everything.
Nice but you need a SATA transceiver for each Flash Card.
SATA allows cables up to 1 meter long. (I don't know what the
minimum is.) I think eSATA allows 2 meters?
Is SATA terminated. If so, the limit on the length is the total
capacitance of the cable.
In addition, PATA cables are wide and block airflow.
I don't think that this is an issue with 2 inch long ones. :-D
SATA cables are much narrower and *far* less of a problem with
airflow. You can get round PATA cables, but those are said to reduce
margins, so you're back to having a higher chance of data loss.
Yes, and yes, but you can also buy another fan for your case.
SATA allows port multipliers, which are like a power cube tap, or a
ethernet/firewire/usb hub. A port multiplier can fan out one SATA
controller port to 15 drives.
That might be a good point. However, Flash Cards are still parallel so
you are going to need a serial to parallel converter for each card.
Also, the total throughput is going to be limited to what SATA can do.
This is going up to 3 Mb/s so that probably isn't an issue.
SATA has NCQ queuing, which is much better than the lame queuing that
PATA has.
Exactly how does this work on the disk end? A tag must be attached to
each queued transaction and the drive must send this to the controller
when it is ready for that data transfer. Is this an enhancement to IDE
drives? If so, it isn't relevant to flash cards unless the cards know
how to do it.
Closer to SCSI's queuing. What we need is a SATA controller that
documents how to use NCQ queuing so that BSD, Plan-9 and Linux can
use it.
Have you looked at SiliconImage's chips?
http://www.siliconimage.com/products/product.aspx?id=27
Note that I think that there is /now/ a standard for SATA, it is just
that the same thing happened as happened with USB: early half broken
chips were produced before the standard was finalized. Unfortunately,
they are still out there and don't have warning labels on them.
--
JRT
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