Is it me or are there many unreliable USB flash drives?

In article , Computer Nerd Kev
wrote:

The maximum voltage ratings would probably only be known by the
memory stick IC manufacturers and their clients, however 5.5V
is a common design maximum. 5.25V is the maximum PSU output
under the ATX specification.

this isn't about atx, it's about usb, which clearly states that 5.25v
is the maximum, regardless of who makes it.

In article , Computer Nerd Kev
wrote:


If the USB insert preferred term sticks get hot in different
computers then the failure isn't in the computer after all. unless
the stress under the 5V high voltage has causes parts of them
to short and now they're heating up at normal voltage, but
it's unlikely that different models would all fail in that
way.

getting hot is not necessarily a failure.

some usb sticks run hot. others don't. most get warm. it's normal.

Computer Nerd Kev wrote
Rod Speed wrote
Computer Nerd Kev wrote
nospam wrote
Computer Nerd Kev wrote

There are USB voltage meters sold cheaply on Ebay to
show if the USB voltage from a computer is too high/low.
If the USB voltage was far too high, the extra energy
would cause excessive heating of the drive.

if the voltage was too high, not only would it not
be usb compliant, but it would likely fry anything
plugged into it, which is expecting a regulated 5v.

I don't mean by design (although anything's possible
with Chinese knock-off stuff, if that's involved), I mean
due to a failure of the computer hardware.

Now the 5V at the USB ports being high would often only make sense
if they were supplied by a separate line from the power supply.

They are in desktops. That's the whole point of the +5V standby line.

No it isn't.

Yes it is.

The 5V Standby line is to enable the motherboard hardware
to detect when the power switch is pressed, and on many
motherboards it is used to power additional functions
while the computer is off as well.

Like the USB so moving the mouse will wake
the system if you have set it up like that.

If the internal computer components and the USB ports were
both subjected to a failure of the 5V voltage regulation, it
would be very likely to destroy the computer without the
user having any time to worry about their USB accessories.

Depends on how much its out by. Certainly if its out by enough
to see what normally stays at room temp get very hot when
doing nothing with just the USB stick plugged in, doing nothing.

The maximum voltage ratings would probably only be known
by the memory stick IC manufacturers and their clients,

Wrong again, its obviously in the specs of the ics.

But again, irrelevant, because even if that was say 7V, that
isnt going to be enough so the memory sticks that don’t even
get warm when supplied with 5V when not doing anything
get very hot when they are supplied with 7V. Basic physics.

however 5.5V is a common design maximum.

Not with the absolute maximum above which you get damage.

5.25V is the maximum PSU output under the ATX specification.

Irrelevant to a potential fault situation.

Most desktop PCs have standard power supplies that
provide the USB 5V from the same lines as everything else,

That is just plain wrong. Its usually supplied by the +5V standby
line, so you can wake the system by moving the mouse etc.

so it is unlikely that an over-voltage situation
would only affect the USB ports.

You have that completely backwards.

A laptop, however, may have a separate power supply circuit
for the USB 5V. If this failed, and supplied too high a voltage, it
may not sevierely affect the normal operation of the computer.

In fact laptops are more likely to have a
separate +5V line for the same reason.

A power-boosted USB hub with a faulty or incorrectly
specified mains adapter powering it could also be a culprit.

the amount of current sourced is limited by
what the device negotiates from the host.

Current limiting only protects against an over-voltage situation
if the device requires more than the minimum current limit (500mA)
to be damaged. If an IC in the memory stick normally draws 20mA
at 5V, it may draw 28mA at 7V (this based on rough calculations:
5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point),
however the IC may only be rated to sustain 5.5V, so it may be
damaged while only consuming 28mA. The rest of the components
in the memory stick will also be drawing additional power, but
you see that the total power draw is not increased enough to
hit the 500mA maximum if the stick normally draws, say, 100mA?

Another possibility, if you only ever use one USB port (or a group
of similarly affected ones) for testing these memory sticks, is
that a high resistance in the computer's USB socket is causing
the _socket_ to heat up, and the heat is being transferred
to the drives themselves via the USB connector. Here, not only
the heat, but also the coresponding reduced power to the memory
stick, may induce irrecoverable write errors or other failures.

unlikely.

Such failures are known to occour due to strain on solder joints
causing them to break, or joints that weren't correctly soldered
in the first place. It is a less common failure, but it's also
uncommon to consume large quantities of memory sticks.

But doesn?t explain why all the sticks get hot.

"a high resistance in the computer's USB socket is causing
the _socket_ to heat up, and the heat is being transferred
to the drives themselves via the USB connector."

Even sillier than you usually manage. That would see the
connector much hotter than the body of the stick itself.

The socket is the bit in the computer.

Duh.

If the same socket/s are used,

It isnt. He gets the same problem with more than one computer.

all the USB memory sticks drawing the same, or similar, currents

They don’t.

will get hotter than normal.

Even sillier than you usually manage.

They will also receive less voltage than otherwise
due to the voltage drop over the resistance of the
failed solder joint - which is waht causes the heat.

Even sillier than you usually manage with the minimal
current that USB sticks use when doing nothing.

"nospam" wrote in message
...
In article , Computer Nerd Kev
wrote:


If the USB insert preferred term sticks get hot in different
computers then the failure isn't in the computer after all. unless
the stress under the 5V high voltage has causes parts of them
to short and now they're heating up at normal voltage, but
it's unlikely that different models would all fail in that
way.

getting hot is not necessarily a failure.

some usb sticks run hot. others don't. most get warm. it's normal.

NOT WHEN DOING NOTHING it isnt.

On 10-23-2016 20:31, Computer Nerd Kev wrote:
No it isn't. The 5V Standby line is to enable the motherboard
hardware to detect when the power switch is pressed, and on
many motherboards it is used to power additional functions
while the computer is off as well.

On my Macbook, unplugging a mouse after putting it to sleep
would wake it up again.

For your reference, records indicate that
nospam wrote:

getting hot is not necessarily a failure.

some usb sticks run hot. others don't. most get warm. it's normal.

Normal or not, it can still be a contributing factor to failure. The
first iPod I got was a HD-based one, and if I left it attached to my
computer to use as a disk it would get *blazingly* hot. I did that
often enough that I have no doubt that it contributed to its drive
failure.

Likewise, if a particular thumb drive runs hot, maybe it isn’t
designed to “normally� be constantly attached. Nobody should make a
blanket assumption that they know what will and won’t cause a
specific failure.

--
"Also . . . I can kill you with my brain."
River Tam, Trash, Firefly

In comp.sys.ibm.pc.hardware.storage Rod Speed wrote:
Computer Nerd Kev wrote
Rod Speed wrote
Computer Nerd Kev wrote
nospam wrote
Computer Nerd Kev wrote

There are USB voltage meters sold cheaply on Ebay to
show if the USB voltage from a computer is too high/low.
If the USB voltage was far too high, the extra energy
would cause excessive heating of the drive.

if the voltage was too high, not only would it not
be usb compliant, but it would likely fry anything
plugged into it, which is expecting a regulated 5v.

I don't mean by design (although anything's possible
with Chinese knock-off stuff, if that's involved), I mean
due to a failure of the computer hardware.

Now the 5V at the USB ports being high would often only make sense
if they were supplied by a separate line from the power supply.

They are in desktops. That's the whole point of the +5V standby line.

No it isn't.

Yes it is.

The 5V Standby line is to enable the motherboard hardware
to detect when the power switch is pressed, and on many
motherboards it is used to power additional functions
while the computer is off as well.

Like the USB so moving the mouse will wake
the system if you have set it up like that.

Standby 5V isn't there for when the computer is in standby, but
when it's (as far as the user is concerned) powered off - look
it up, or just plug a working power supply in to the mains and
look for the standby 5V even when there's no motherboard attached
and it's in its powered-off state - there'll be 5V on the "standby"
supply line.

Actually, I'm such a nice guy that I've found a link for you:
http://www.pcguide.com/ref/power/sup...ftPower-c.html

If the internal computer components and the USB ports were
both subjected to a failure of the 5V voltage regulation, it
would be very likely to destroy the computer without the
user having any time to worry about their USB accessories.

Depends on how much its out by. Certainly if its out by enough
to see what normally stays at room temp get very hot when
doing nothing with just the USB stick plugged in, doing nothing.

The maximum voltage ratings would probably only be known
by the memory stick IC manufacturers and their clients,

Wrong again, its obviously in the specs of the ics.

Which most often won't be viewable by the general public.
What's the actual model number of the flash chips in your
memory sticks?

But again, irrelevant, because even if that was say 7V, that
isnt going to be enough so the memory sticks that don?t even
get warm when supplied with 5V when not doing anything
get very hot when they are supplied with 7V. Basic physics.

however 5.5V is a common design maximum.

Not with the absolute maximum above which you get damage.

Why I said design maximum. Absolute maximums are not always
specified. 7V is common with some families of 5V ICs.

5.25V is the maximum PSU output under the ATX specification.

Irrelevant to a potential fault situation.

Just perspective.

Most desktop PCs have standard power supplies that
provide the USB 5V from the same lines as everything else,

That is just plain wrong. Its usually supplied by the +5V standby
line, so you can wake the system by moving the mouse etc.

so it is unlikely that an over-voltage situation
would only affect the USB ports.

You have that completely backwards.

A laptop, however, may have a separate power supply circuit
for the USB 5V. If this failed, and supplied too high a voltage, it
may not sevierely affect the normal operation of the computer.

In fact laptops are more likely to have a
separate +5V line for the same reason.

A power-boosted USB hub with a faulty or incorrectly
specified mains adapter powering it could also be a culprit.

the amount of current sourced is limited by
what the device negotiates from the host.

Current limiting only protects against an over-voltage situation
if the device requires more than the minimum current limit (500mA)
to be damaged. If an IC in the memory stick normally draws 20mA
at 5V, it may draw 28mA at 7V (this based on rough calculations:
5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point),
however the IC may only be rated to sustain 5.5V, so it may be
damaged while only consuming 28mA. The rest of the components
in the memory stick will also be drawing additional power, but
you see that the total power draw is not increased enough to
hit the 500mA maximum if the stick normally draws, say, 100mA?

Another possibility, if you only ever use one USB port (or a group
of similarly affected ones) for testing these memory sticks, is
that a high resistance in the computer's USB socket is causing
the _socket_ to heat up, and the heat is being transferred
to the drives themselves via the USB connector. Here, not only
the heat, but also the coresponding reduced power to the memory
stick, may induce irrecoverable write errors or other failures.

unlikely.

Such failures are known to occour due to strain on solder joints
causing them to break, or joints that weren't correctly soldered
in the first place. It is a less common failure, but it's also
uncommon to consume large quantities of memory sticks.

But doesn?t explain why all the sticks get hot.

"a high resistance in the computer's USB socket is causing
the _socket_ to heat up, and the heat is being transferred
to the drives themselves via the USB connector."

Even sillier than you usually manage. That would see the
connector much hotter than the body of the stick itself.

YES. But with it mostly inside the computer, the user is
unlikely to notice that difference.

The socket is the bit in the computer.

Duh.

If the same socket/s are used,

It isnt. He gets the same problem with more than one computer.

Yep, and that bit of information means that this isn't the problem,
so I hereby terminate this argument, my points all adequately
made to the satisfaction of anyone sensible.

--
__ __
#_ |\| | _#

In comp.sys.ibm.pc.hardware.storage nospam wrote:
In article , Computer Nerd Kev
wrote:


A laptop, however, may have a separate power supply circuit for
the USB 5V. If this failed, and supplied too high a voltage, it
may not sevierely affect the normal operation of the computer.

no.

Yes. If the 5V supply circuit was built separately for use by
the relatively high current USB devices, it's failure (in this
way) would not stop the computer operating. In some cases it
might (I won't spend the time spelling it out), but if no USB
devices are connected, it won't.

usb devices are not 'relatively high current'.

usb originally specified a maximum of 500ma. the usb charging spec can
go to about 2a, and at 5v, is just 10w.

It is for a laptop with internal hardware designed to conserve power
consumption as much as possible for the longest possible battery
operation time.

A power-boosted USB hub with a faulty or incorrectly specified
mains adapter powering it could also be a culprit.

no hub was used.

Known now, yes.

it was known before.

OK, missed it. You did too based on your earlier reply to Ant.

the amount of current sourced is limited by what the device
negotiates from the host.

Current limiting only protects against an over-voltage situation
if the device requires more than the minimum current limit (500mA)
to be damaged. If an IC in the memory stick normally draws 20mA
at 5V, it may draw 28mA at 7V (this based on rough calculations:
5V / 0.02A = 250R 7V / 250R = 0.028A, but it proves the point),
however the IC may only be rated to sustain 5.5V, so it may be
damaged while only consuming 28mA. The rest of the components
in the memory stick will also be drawing additional power, but
you see that the total power draw is not increased enough to
hit the 500mA maximum if the stick normally draws, say, 100mA?

usb devices don't work that way.

OK, so the device can specify roughly the current it needs via
the USB protocol, which if you're lucky will be respected by the
computer hardware.

luck has absolutely *nothing* to do with it.

the usb spec *requires* that a usb peripheral device use *up* *to*
100ma and then negotiate higher current requirements, which the usb
host can deny.

anything else is not compliant with the usb spec.

Some cheap designs aren't, that's the luck.

The current specification isn't accurate
enough to prevent damage though, for the reason shown above.
The current increase as voltage is increased isn't great enough
to trip the limiting.

no.

Again, YES. You're arguments aren't very convincing.

Another possibility, if you only ever use one USB port (or a group
of similarly affected ones) for testing these memory sticks, is
that a high resistance in the computer's USB socket is causing
the _socket_ to heat up, and the heat is being transferred
to the drives themselves via the USB connector. Here, not only
the heat, but also the coresponding reduced power to the memory
stick, may induce irrecoverable write errors or other failures.

unlikely.

Such failures are known to occour due to strain on solder joints
causing them to break, or joints that weren't correctly soldered
in the first place.

broken joints don't get hot. they simply don't work.

Sometimes they simply form a high resistance. Look it up - dry
joints.

they're commonly called cold solder joints, and will cause a device to
fail not get hot.

They're commonly called as many things as USB memory sticks are, just
look up their failure modes and you'll see that they can get hot. It's
the same as a power plug with corroded/tarnished contacts getting hot.

It is a less common failure, but it's also
uncommon to consume large quantities of memory sticks.

it's not uncommon at all. memory sticks are cheap enough to be
considered disposable. sometimes they're even given away for free.

As I remember it, OP figures that he's bought good ones - hence
his confusion about the cause of the failure rate.

it wasn't due to heat.

Maybe not, but they were apparantly getting unusually hot - sounds
like a potential connection to me.

--
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I'd recommend Muskin Ventura Pro. Has wear levelling and some good
algorithms against failure. Mine has been great.

BTW The cap snaps onto the end while you're using it.
--
Ed Light

Better World News TV Channel:
http://realnews.com

Send spam to the FTC at

Thanks, robots.