Prev: BIOS not detecting hard drive
Next: Recomeneded 2.5" external enclosure?
From: Arno on 24 Apr 2010 20:18
Mike Tomlinson <mike(a)jasper.org.uk> wrote:
> In article <83g67vFpanU1(a)mid.individual.net>, Arno <me(a)privacy.net>
> writes

>>Again, how do you know that? I think you are deep in the real
>>of wishful thinking here...

> You're talking to another Woddles morph. Never engage in a battle of
> wits with an unarmed man.

Agreed. I had some suspicion, but only later and did not want to
delete the already written answers for possible value to others
here.

Arno

--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno(a)wagner.name
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
From: William R. Walsh on 26 Apr 2010 22:11
Hi!

> It works fine for the lower powered devices like mice etc.

The key word there being "lower powered". :-)

> Not if its properly designed.

That is anyone's guess. Have you seen some of the USB cards that are on the
market today? Seriously, you can buy some of them for $1 *new* and a little
shipping from someone in Hong Kong, China or similar locations.

Many have VIA chipsets, and the later ones (VT6212, 6214) seem to do what
they should when put on a reasonably well built card. Still, I doubt there's
much change from that $1 left to put much quality into the card...probably
just enough to throw some solder at the components and hope they stick in
approximately the right locations. Some chipsets (in particular the ones
from Acer Labs) don't really seem to work in USB 2.0 mode, especially on a
non-Windows OS. (BTDTGTTS*)

I've seen some of these cards that have excellent USB chipsets (NEC) and yet
the card maker still does things they should not--like splitting off one USB
port into two that may not be used at the same time. (It works fine until
you connect a USB 2.0 device, and then you get random failures. The other,
normal ports work fine.)

I'd hope motherboards were better designed than these disasters. I wouldn't
bet on it, especially with cheaper or no-name boards.

> Not if the device being powered is properly designed.

The same can be said for a lot of storage enclosures as the USB cards above.
They're only just good enough a lot of the time.

William

* cringe


From: Rod Speed on 26 Apr 2010 23:12
William R. Walsh wrote

>>> I've always been leery of storage devices that claim to be 100% USB powered.

>> It works fine for the lower powered devices like mice etc.

>>> Most of them having moving parts usually come with a "Y" cable
>>> that draws power from USB ports in the expectation of getting
>>> 1 amp total, rather than the expense (and possible inconvenience)
>>> of providing a separate plug-in power supply.

>> Only the high power devices. You dont get that with mice etc.

>>> Sometimes I'm in a situation where there is only one free USB port.

>> You can always add a powered hub.

>>> Other times, I'm still distrustful - like the portable DVD
>>> burner whose manufacturer's drive specs tell me that
>>> it may very well draw more than 1 ampere at a time.

>> Plenty of powered hubs handle that fine.

>>> For that reason I've taken to connecting a wall-wart that provides 5V
>>> USB power to the dummy plug on the other end of that "Y" connector.

>> Makes more sense to get one with a USB socket.

>>> But then, I'm worried again. Does the back current from
>>> an external PS pose any danger to the PC's USB ports?

>> Not if its properly designed.

> That is anyone's guess. Have you seen some of the USB cards that are
> on the market today? Seriously, you can buy some of them for $1 *new*
> and a little shipping from someone in Hong Kong, China or similar locations.

Yeah, tho you can often inspect those visually for that particular question.

> Many have VIA chipsets, and the later ones (VT6212, 6214) seem to do
> what they should when put on a reasonably well built card. Still, I doubt
> there's much change from that $1 left to put much quality into the card...

They dont need to, they just steal the design.

> probably just enough to throw some solder at the components
> and hope they stick in approximately the right locations.

> Some chipsets (in particular the ones from Acer Labs)
> don't really seem to work in USB 2.0 mode, especially
> on a non-Windows OS. (BTDTGTTS*)

Never seen that myself.

> I've seen some of these cards that have excellent USB chipsets
> (NEC) and yet the card maker still does things they should not--like
> splitting off one USB port into two that may not be used at the same
> time. (It works fine until you connect a USB 2.0 device, and then you
> get random failures. The other, normal ports work fine.)

Yeah, the cheap chinese stuff can be a hell of a problem in that regard.

But its so cheap you can just chuck it in the bin when you find one of those.

> I'd hope motherboards were better designed than these disasters.
> I wouldn't bet on it, especially with cheaper or no-name boards.

I normally stick with Asus or Gigabyte etc.

>> Not if the device being powered is properly designed.

> The same can be said for a lot of storage enclosures as the USB cards above.
> They're only just good enough a lot of the time.

I use HD docking stations myself. Mainly because my main need
is for overflow from the PVRs and they work very well for that.


From: William R. Walsh on 1 May 2010 13:56
Hi!

> They dont need to, they just steal the design.

There's usually a reference design in the datasheets for the IC they use.
It's the other parts that I'm talking about--they probably leave off
everything that isn't strictly necessary, like 'suggested' capacitors or
circuit protection.

I try to stay away from them for that reason.

> Never seen that myself.

I can't say for sure about Linux, as I only have it on a few machines. But
FreeBSD and the MacOS really don't like the Acer chipsets for USB or
USB/Firewire. I've had a few different boards that used some Acer chip and
none of them worked for USB 2.0 on those operating systems. Most frequently
data transfers would just stall. It wouldn't usually take the OS down, but
the failures would produce tons of complaining on the system console.

Oddly enough, the Firewire part of those chipsets that did both USB and
Firewire worked perfectly. And they worked on Windows (probably the only OS
tested by the chipset maker?).

> I normally stick with Asus or Gigabyte etc.

Not everyone will. Some folks only care about the price, and therefore get
what they deserve. I hate it when machines with no-name parts of dubious
quality come in for repair, because it just can't always be done.

William


From: Rod Speed on 1 May 2010 16:09
William R. Walsh wrote:

>>>>> I've always been leery of storage devices that claim to be 100% USB powered.

>>>> It works fine for the lower powered devices like mice etc.

>>>>> Most of them having moving parts usually come with a "Y" cable
>>>>> that draws power from USB ports in the expectation of getting
>>>>> 1 amp total, rather than the expense (and possible inconvenience)
>>>>> of providing a separate plug-in power supply.

>>>> Only the high power devices. You dont get that with mice etc.

>>>>> Sometimes I'm in a situation where there is only one free USB port.

>>>> You can always add a powered hub.

>>>>> Other times, I'm still distrustful - like the portable DVD
>>>>> burner whose manufacturer's drive specs tell me that
>>>>> it may very well draw more than 1 ampere at a time.

>>>> Plenty of powered hubs handle that fine.

>>>>> For that reason I've taken to connecting a wall-wart that provides 5V
>>>>> USB power to the dummy plug on the other end of that "Y" connector.

>>>> Makes more sense to get one with a USB socket.

>>>>> But then, I'm worried again. Does the back current from
>>>>> an external PS pose any danger to the PC's USB ports?

>>>> Not if its properly designed.

>>> That is anyone's guess. Have you seen some of the USB cards that are
>>> on the market today? Seriously, you can buy some of them for $1 new
>>> and a little shipping from someone in Hong Kong, China or similar locations.

>> Yeah, tho you can often inspect those visually for that particular question.

>>> Many have VIA chipsets, and the later ones (VT6212, 6214) seem to do
>>> what they should when put on a reasonably well built card. Still, I doubt
>>> there's much change from that $1 left to put much quality into the card...

>> They dont need to, they just steal the design.

> There's usually a reference design in the datasheets for the IC they use.

That isnt what the best of the designs use tho.

> It's the other parts that I'm talking about--they probably leave off
> everything that isn't strictly necessary, like 'suggested' capacitors

They're mostly designed not to need those now.

> or circuit protection.

Thats mostly built in too now.

>>> probably just enough to throw some solder at the components
>>> and hope they stick in approximately the right locations.

>>> Some chipsets (in particular the ones from Acer Labs)
>>> don't really seem to work in USB 2.0 mode, especially
>>> on a non-Windows OS. (BTDTGTTS*)

>>> I try to stay away from them for that reason.

>> Never seen that myself.

> I can't say for sure about Linux, as I only have it on a few
> machines. But FreeBSD and the MacOS really don't like
> the Acer chipsets for USB or USB/Firewire. I've had a
> few different boards that used some Acer chip and none
> of them worked for USB 2.0 on those operating systems.

Presumably someone fucked up with the driver given they work fine with other OSs.

> Most frequently data transfers would just stall.
> It wouldn't usually take the OS down, but the failures
> would produce tons of complaining on the system console.

Like I said, presumably someone fucked up with the driver.

> Oddly enough, the Firewire part of those chipsets
> that did both USB and Firewire worked perfectly.

More evidence that someone fucked up with the driver.

> And they worked on Windows (probably
> the only OS tested by the chipset maker?).

Very likely.

>>> I've seen some of these cards that have excellent USB chipsets
>>> (NEC) and yet the card maker still does things they should not--like
>>> splitting off one USB port into two that may not be used at the same
>>> time. (It works fine until you connect a USB 2.0 device, and then you
>>> get random failures. The other, normal ports work fine.)

>> Yeah, the cheap chinese stuff can be a hell of a problem in that regard.

>> But its so cheap you can just chuck it in the bin when you find one of those.

>>> I'd hope motherboards were better designed than these disasters.
>>> I wouldn't bet on it, especially with cheaper or no-name boards.

>> I normally stick with Asus or Gigabyte etc.

> Not everyone will. Some folks only care about the price, and therefore
> get what they deserve. I hate it when machines with no-name parts of
> dubious quality come in for repair, because it just can't always be done.

Sure, but the replacements are so cheap it doesnt really matter much.


First  |  Prev  | 
Pages: 1 2 3
Prev: BIOS not detecting hard drive
Next: Recomeneded 2.5" external enclosure?