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"BIOS problem" solved



 
 
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  #21  
Old November 8th 14, 02:48 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Brian Gregory
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Posts: 9
Default "BIOS problem" solved

On 06/11/2014 09:22, Rod Speed wrote:
J. P. Gilliver (John) wrote
Rod Speed wrote


I've never had a problem with my samsungs.


Sounds painful!


Nope, completely painless.
Any of the small molecular weight alcohols are fine.


The SATA cable should not be bent until it kinks.


That's true of any signal cable like that.


This has an impact on the dielectric insulation inside the cable.
And can change the cable impedance.


Cable impedance just isnt a problem with digital signals.


If it wasn't, you wouldn't be worrying about kinks above.


I don't worry about kinks above.
It's an analogue world


Nope.
- especially at the sort of frequencies we work at these days.


Not in the sense that the cable impedance matters.
But even back in the days of 10 megabit ethernet, impedance was
relevant (75 ohm coax, IIRR). That's why, ideally, you had terminators.


But PATA didn't and SATA doesn't either.


I'm sure SATA does have terminators, it's just that they're built in to
the devices at the ends of the cable, and there are no devices connected
anywhere in the middle of the cable.

My understanding is that PATA does too but that they're not terminated
very precisely, so that whether you have one drive or two it still works
"well enough".

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.
  #22  
Old November 8th 14, 02:51 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Brian Gregory
external usenet poster
 
Posts: 9
Default "BIOS problem" solved

On 07/11/2014 05:34, Paul wrote:
Gene E. Bloch wrote:


What does all that have to do with my youthful "understanding" of wire?


Well, my young friend, this is wire with blue
chewing gum inside. Try a bite...

http://www.satacables.com/assets/images/IMG_188353.jpg

Pauk


So are you saying reflections off a kinked cable will be too small to
matter or that the cable is so short that reflections don't matter?

It almost sounds as if you're saying, the more ludicrous thing - that
the cable doesn't have a characteristic impedance.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.
  #23  
Old November 8th 14, 07:53 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Paul
external usenet poster
 
Posts: 13,364
Default "BIOS problem" solved

Brian Gregory wrote:
On 07/11/2014 05:34, Paul wrote:
Gene E. Bloch wrote:


What does all that have to do with my youthful "understanding" of wire?


Well, my young friend, this is wire with blue
chewing gum inside. Try a bite...

http://www.satacables.com/assets/images/IMG_188353.jpg

Pauk


So are you saying reflections off a kinked cable will be too small to
matter or that the cable is so short that reflections don't matter?

It almost sounds as if you're saying, the more ludicrous thing - that
the cable doesn't have a characteristic impedance.


1) The cable does have a characteristics impedance. The SATAIO
committee has some test procedures for the cable, if you want
more details about what they test for. The Z0_diff is likely to
be 100 ohms. (There are a number of high speed differential
interconnects that work the same way. LVDS is where the fun
started. We had some proprietary interfaces at work, which
predate LVDS, but they don't count, as they were a trifle
crappy and a lot slower.)
2) The receiver has a differential termination resistor inside
the chip housing. That terminates the line. If there wasn't
a resistor in there, you could do fly-by termination.
3) Kinking or creasing the cable, compresses the blue-colored
dielectric in the twinaxial thing. You can get a reflection
off such a discontinuity.
4) The receiver is differential, and subtracts the signal from the
two conductors in the twinax. When common mode noise is present
on the cable, the receiver can eliminate the noise, by taking the
difference. That also makes it a little difficult to predict
what will happen if one or both conductors has a reflection on it.
My suspicion is, kinking just one of the two dielectric areas,
makes for a worse result.

I'd hoped that someone on the Internet, had taken their SATA test
gear, and bent a cable to see how much effect it has.

If such a test result is not available, SATA packet transmission has a CRC
error detector, and you could use counted cable errors as an indication
of cabling damage.

http://mindshare.com/files/ebooks/SA...Technology.pdf

"In contrast, every packet of information sent across the SATA bus
includes a Cyclic Redundancy Check (CRC). These checks are designed
to detect every sin-gle and double-bit error that occurs. There
exists an extremely high probability that CRC will detect
virtually every error."

So there is a way of determining that conditions are not the
best on the cable. I thought one of the SMART indicators (one
which cannot be cleared or reset), counted those on the
drive end.

While that Mindshare sentence expresses some optimism about the
CRC code, I don't share that optimism. CRC can suppress errors
and make the overall error characteristic about three orders of
magnitude better than it might otherwise be (you can request
retransmission if an error is detected). The presence of
the CRC, does not imply that data corruption will never occur.
Which is why, when CRC errors are detected and counted, you
want to fix or replace the problematic cable. Before a multi-bit
error burst does slide through.

Paul
  #24  
Old November 8th 14, 10:43 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Gene E. Bloch[_3_]
external usenet poster
 
Posts: 98
Default "BIOS problem" solved

On Fri, 7 Nov 2014 13:19:00 +0100, Linea Recta wrote:

"Gene E. Bloch" schreef in bericht
...
On Thu, 06 Nov 2014 05:34:42 -0500, Paul wrote:

Rod Speed wrote:


That isnt going to happen with a SATA cable.

Thanks for providing the incentive for me to keep searching.

http://h20566.www2.hp.com/portal/sit...4892.199480143

"Never bend a SATA data cable tighter than a 30 mm (1.18 in) radius.
Never crease a SATA data cable."

Notice that SATA power cables are not mentioned. This is because SATA
power cables are not coaxial or twinaxial in nature, and there is
no AC impedance to worry about in that respect. A SATA Power cable should
not be bent so tightly as to break the copper wire inside.

Paul


Apropos of nothing (although I offer thanks for being motivated to look
further above!), I still remember as a child not understanding how
electricity could still get to the light bulb when there was a knot in
the wire.

Although some here might think otherwise, by "child" I mean when I was a
kid of 4 years of age, not when I was 19 years old.

--


I always thought that uploading to a friend in Switserland took more time
than the other way round because it had to go up the mountains!


You also have to deal with a redshift due to relativistic effects. It
wild be a blueshift going downhill.

Or is it the other way around?

--
Gene E. Bloch (Stumbling Bloch)
  #25  
Old November 8th 14, 10:45 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Gene E. Bloch[_3_]
external usenet poster
 
Posts: 98
Default "BIOS problem" solved

On Fri, 07 Nov 2014 00:34:31 -0500, Paul wrote:

Gene E. Bloch wrote:


What does all that have to do with my youthful "understanding" of wire?


Well, my young friend, this is wire with blue
chewing gum inside. Try a bite...

http://www.satacables.com/assets/images/IMG_188353.jpg

Pauk


To tell the truth, I don't think any of the things you've mentioned or
linked to are a problem for standard lampcord at 60Hz (though it was
called 60 cycles back then).

--
Gene E. Bloch (Stumbling Bloch)
  #26  
Old November 8th 14, 10:50 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Godzilla[_2_]
external usenet poster
 
Posts: 5
Default "BIOS problem" solved

On 2014-11-08, Gene E. Bloch wrote:
On Fri, 7 Nov 2014 13:19:00 +0100, Linea Recta wrote:

"Gene E. Bloch" schreef in bericht
...
On Thu, 06 Nov 2014 05:34:42 -0500, Paul wrote:

Rod Speed wrote:


That isnt going to happen with a SATA cable.

Thanks for providing the incentive for me to keep searching.

http://h20566.www2.hp.com/portal/sit...4892.199480143

"Never bend a SATA data cable tighter than a 30 mm (1.18 in) radius.
Never crease a SATA data cable."

Notice that SATA power cables are not mentioned. This is because SATA
power cables are not coaxial or twinaxial in nature, and there is
no AC impedance to worry about in that respect. A SATA Power cable should
not be bent so tightly as to break the copper wire inside.

Paul

Apropos of nothing (although I offer thanks for being motivated to look
further above!), I still remember as a child not understanding how
electricity could still get to the light bulb when there was a knot in
the wire.

Although some here might think otherwise, by "child" I mean when I was a
kid of 4 years of age, not when I was 19 years old.

--


I always thought that uploading to a friend in Switserland took more time
than the other way round because it had to go up the mountains!


You also have to deal with a redshift due to relativistic effects. It
wild be a blueshift going downhill.

Or is it the other way around?


It's always a money-shift in Switzerland.

--
Godzilla
  #27  
Old November 8th 14, 11:05 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Gene E. Bloch[_3_]
external usenet poster
 
Posts: 98
Default "BIOS problem" solved

On Sat, 8 Nov 2014 14:43:15 -0800, Gene E. Bloch wrote:

On Fri, 7 Nov 2014 13:19:00 +0100, Linea Recta wrote:

"Gene E. Bloch" schreef in bericht
...
On Thu, 06 Nov 2014 05:34:42 -0500, Paul wrote:

Rod Speed wrote:


That isnt going to happen with a SATA cable.

Thanks for providing the incentive for me to keep searching.

http://h20566.www2.hp.com/portal/sit...4892.199480143

"Never bend a SATA data cable tighter than a 30 mm (1.18 in) radius.
Never crease a SATA data cable."

Notice that SATA power cables are not mentioned. This is because SATA
power cables are not coaxial or twinaxial in nature, and there is
no AC impedance to worry about in that respect. A SATA Power cable should
not be bent so tightly as to break the copper wire inside.

Paul

Apropos of nothing (although I offer thanks for being motivated to look
further above!), I still remember as a child not understanding how
electricity could still get to the light bulb when there was a knot in
the wire.

Although some here might think otherwise, by "child" I mean when I was a
kid of 4 years of age, not when I was 19 years old.

--


I always thought that uploading to a friend in Switserland took more time
than the other way round because it had to go up the mountains!


You also have to deal with a redshift due to relativistic effects. It
wild be a blueshift going downhill.

Or is it the other way around?


"it _would_ be a blueshift"

Dumb spell checker won't read my mind...

--
Gene E. Bloch (Stumbling Bloch)
  #28  
Old November 8th 14, 11:29 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Rod Speed
external usenet poster
 
Posts: 8,559
Default "BIOS problem" solved

Brian Gregory wrote
Rod Speed wrote
Paul wrote
Rod Speed wrote
Paul wrote


The SATA cable is a miniature dual twinax (one pair for serial TX, one
pair for RX). And when I say "kink", I'm referring to the compression
of the shield around one of the two conductors in that pair.


That isnt going to happen with a SATA cable.


Thanks for providing the incentive for me to keep searching.


http://h20566.www2.hp.com/portal/sit...4892.199480143


"Never bend a SATA data cable tighter than a 30 mm (1.18 in) radius.
Never crease a SATA data cable."


That isnt for the reason you were talking about.


PLEASE EXPLAIN.


SATA data cables are too short for the effect he is talking about to occur.

Notice that SATA power cables are not mentioned. This is because SATA
power cables are not coaxial or twinaxial in nature, and there is no AC
impedance to worry about in that respect. A SATA Power cable should not
be bent so tightly as to break the copper wire inside.



  #29  
Old November 8th 14, 11:34 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Rod Speed
external usenet poster
 
Posts: 8,559
Default "BIOS problem" solved

Brian Gregory wrote
Rod Speed wrote
J. P. Gilliver (John) wrote
Rod Speed wrote


I've never had a problem with my samsungs.


Sounds painful!


Nope, completely painless.


Any of the small molecular weight alcohols are fine.


The SATA cable should not be bent until it kinks.


That's true of any signal cable like that.


This has an impact on the dielectric insulation inside the cable.
And can change the cable impedance.


Cable impedance just isnt a problem with digital signals.


If it wasn't, you wouldn't be worrying about kinks above.


I don't worry about kinks above.


It's an analogue world


Nope.


- especially at the sort of frequencies we work at these days.


Not in the sense that the cable impedance matters.


But even back in the days of 10 megabit ethernet, impedance was
relevant (75 ohm coax, IIRR). That's why, ideally, you had terminators.


But PATA didn't and SATA doesn't either.


I'm sure SATA does have terminators,


But not impedance matching terminators in the sense he is talking about.

it's just that they're built in to the devices at the ends of the cable,
and there are no devices connected anywhere in the middle of the cable.


Not in the sense of impedance matching he is talking about.

SATA data cables are too short for that approach to be needed.

My understanding is that PATA does too


No it does not, and they arent coax either.

but that they're not terminated very precisely,


Neither is SATA.

so that whether you have one drive or two it still works "well enough".


They donít do impedance matching
in the sense he is talking about.

And when you have just the motherboard on
one end and a drive on the middle connector,
and nothing on the end connector, that end
connector isnt even terminated at all.


  #30  
Old November 8th 14, 11:36 PM posted to alt.windows7.general,comp.sys.ibm.pc.hardware.storage
Rod Speed
external usenet poster
 
Posts: 8,559
Default "BIOS problem" solved



"Brian Gregory" wrote in message
...
On 07/11/2014 05:34, Paul wrote:
Gene E. Bloch wrote:


What does all that have to do with my youthful "understanding" of wire?


Well, my young friend, this is wire with blue
chewing gum inside. Try a bite...

http://www.satacables.com/assets/images/IMG_188353.jpg


So are you saying reflections off a kinked cable will be too small to
matter


Whether he is saying that or not, that is true.

or that the cable is so short that reflections don't matter?


Whether he is saying that or not, that is true.

It almost sounds as if you're saying, the more ludicrous thing - that the
cable doesn't have a characteristic impedance.


He wasnít saying that.

 




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