TwistyCreek wrote:
The "S" in USB stands for SERIAL. Universal Serial Bus. Serial means
one bit at a time. Knowing this, the speeds are rated in bits per
second not bytes (groups of 8 bits). Lets do the math to break it down
to how it works (one bit at a time, so down to bits). USB 2.0
*averages* about 320Mbs (megabits per second) even though the spec
says 480Mbs, while USB 1.1 only runs at 12 Mbps. (I can't pull the
speed for 1.0 out of my head but I think they're relatively the same.)
Since yours is a PCI card, it wont send data on the external bus, it
will sent its data on the PCI bus, which will stack along with the
other PCI devices in memory and receives an interrupt from the host,
which then triggers the PCI interupt to the CPU. This will probably
limit you to the 320Mbs at best. (if that last part doesn't make sense
don't worry, just suffice it to say you can't acheive 480Mbs).

The first thing to remember doing the math is that you cannot apply the
decimal (base 10) number system, because computers use the binary (base
2) system. Therfore, a kilobit does not equal 1000 bits, it equals
2^10 (two to the power of 10) bits or 1024 bits. and a megabit does not
equal 1000000 bits its 2^20 or 1048576 bits. So when it says 480Mbs
that means 1048576*480 to get actual bits per second, or 503316480
bits/s. Since we're estimating the fastest you could go at 320 we'll
do that. Hell, lets do both. Hell, lets do all three! The other two:
320*1048576 = 335544320 bits per second estimated max. And 12*1048576 =
12582912 bits per second on USB 1.1

So here we are:

Theoretical max: 503316480 bits/s
Estimated max: 335544320 bits/s
USB 1.1: 12582912 bits/s


Now that we have the real numbers, we just need to do one more
conversion:

Your ~ 1.5Giga BYTES of data is 1.5*(2^30 bits * 8). Hope this leap
makes common sense. We're using the binary system to get a gigabit,
multiplying by 8 to get gigabytes, then multiplying that total by 1.5
so its a gigabyte and a half. The answer is 12884901888 bits. Thats a
butt-load of bits. 12 billion, 884 million 901 thousand 888 bits.
Maybe a butt-load and a pant-load. Or vise-versa, I digress.

So at "theoretcal max" it should take 12884901888 / 503316480 seconds,
or 25.6 seconds.

and at Estimated max it should take 12884901888 / 335544320 seconds, or
38.4 seconds

and USB 1.1 max (theoretical remember) should take 12884901888 /
12582912 seconds, or 1024 seconds or 17 minutes.

Hope this helps put your performance in perspective. I doubt you're
even coming close to that number. They don't call it WinDOZE for
nothing. (that's most likely your bottleneck).

For those poindexters out there that want to remind me that storage
systems aren't beholden to the base2 definitions or GibiBits, I'll add
as an appendix the "true storage" gigabyte which is 10^9 or one billion
bytes. One billion sets of 8 bits. 1.5*(10^9 * 8) or 12,000,000,000
bits. An even 12 billion bits. It should take 12884901888 / 503316480
or 23.84 seconds.

All these GB/s and Gibi-somethings and kilo whatevers are confusing.
These SI units should be replaced with the previously mentioned butt
and pant loads. I need to back up a butt-load of data. That should be
sufficient or i need to download 3.2 pant-loads at 180 butt-loads per
second. How long will that take?

x1134x

P.S. Please feel free to tear my math apart incase I smoked crack and
don't remember smoking it. I'm humble enough to admit when I'm wrong.

Is your XP running service pack 1? if not, install it.
"xxxx" <anon@comments.header> wrote in message
news:WVNP2LKK38857.0159722222@twistycreek.com...

xxxx wrote:
Goto device manager. (right click My Computer choose manage, click the
device manager on the left of the window that pops up. FInd your USB
adapter(s) in the right hand pane, and expand it. Try to see if you
have any indication of USB 2.0 or ENHANCED USB or ENHANCED PCI to USB.
If so, you have the right driver.

Also get the SP1.

x1134x

xxxx wrote:
That one is your USB2.0 driver.


You're probably NOT going to get the max usb speed out of windoze
without a lot of tweaking. And even then your still not going to get
it. Check the specs of your USB hd plug to see the max data rate it
supports.

x1134x

Sorry, did you mention the PCI bus speed?

Eg., my HP has 100 mhz FSB, so even with my USB2.0 PCI card I cannot
approach the USB2 max rates. I need the USB2 protocols to connect devices
that are not supported by USB1.1 -- but I won't get USB2.0 speeds until I
upgrade to a computer that supports it.

Hopefully, you have a newer 433 mhz bus -- in which case my comments would
be irrelevent.

Good Luck

On Sat, 20 May 2006 11:14:20 -0700, xxxx <anon@comments.header> wrote:



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Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

Sorry, did you list your computer's bus speed?

For example, my HP has only a 100 MHz FSB, so I cannot approach the USB
2.0 max rates with my PCI USB 2 card. (I need the card, tho, so that I can
access USB 2 only devices like my iPod.)

Anyway, I hope that your computer is a more recent 433 MHz, and that my
comments are irrelevant.

Good Luck

On Sat, 20 May 2006 11:14:20 -0700, xxxx <anon@comments.header> wrote:



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Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

Michael wrote:
Mike, get a computer basics book and study it. If you go start, run,
and type in calc, you have a calculator already on your pc. Use them
both to understand how a pc works.

First of all the PCI bus speed is not the FSB speed they are two
different busses. The fastest the PCI bus speed could possibly be is
133MHz on a very new pc, but most PCI cards won't support that, nor
would they support a 66Mhz bus. The PCI specification for the bus is
33MHz. That being said even a 33Mhz bus will not bottleneck serial
communications. Lets do math! (Its fun!)

First since we know how computers work, we know that the bus is NOT
serial communication it is parrallel. Both the PCI bus and the FSB
(the bus that feeds data into the CPU from all other busses) operate at
32 bits. That means it can handle 32/8 or 4 bytes per clock cycle. Hz
meant Hertz, which is a unit for cycles per second. Mhz is 1 million
cycles per second or 1000000Hertz. Total bit handling capacity then
for 33Mhz is 32*(33*1000000) or 33000000*32 or 1056000000 bits/second.

remember the speeds for USB?

Theoretical max: 503316480 bits/s
Estimated max: 335544320 bits/s
USB 1.1: 12582912 bits/s

Bus speed @ 33Mhz: 1056000000 bits/second. That's exactly twice as
fast as the theoretical max of USB 2.0 which we know cannot be
acheived. Therefore, any bus within the computer operates fast enough
to handle the serial communication of USB.

x1134x