US is the wrong sobriquet for this problem. Flex and TC are in the
process of checkout and certification of a fixed collection of firewire
cards, assets. But here is my BO for the day, no matter how much it stinks:
Bob's Opinions (BO)
NEVER EVER use a laptop for real time embedded applications like
software radio. Just say no irrespective of how much you love the
device and its convenience they are simply ill suited to the task. Flex
has just spent 3.5 weeks wasting >$100/hour of billable time of its most
valuable software engineer EMPLOYEE wasting time on a laptop which could
not be made to function so they could have a known reliable laptop for
shows. Time that should have been spent on software things, including
new architecture architecting. ;-)
Laptop's are UTTERLY unpredictable hardware. You will know the
processor and that is IT. Unless you pay top dollar and get a
"guaranteed the same" laptop, they always take the cheapest motherboard
they can get that week. Companies like Dell have a bin for everything
when they build the cheap machines, including desktops, and they just
grab the part that fits the job and whatever is in the bin goes into the
PC. In the case of laptop's, they are ALWAYS trying to shave a buck or
two off the cost. Sell a million laptops and that is lots of money.
Laptops are about saving power. They are NEVER about high end, how
power, low latency computing EVER.
The problem you are experiencing is either a firewire driver/firewire
firmware/firewire hardware issue and that is just out of the ability of
Flex or the developers to control. The software is at the mercy of your
firewire vendor. Flex already knows this is its major problem at this
time period. If Dudley could ever stop answering the phone long enough
(from fixing firewire problems), he has the task of buying a pile of
cards and finding what works on what machine with this or that OS.
This is for cardbus laptops and PCIe cards for desktops.
No one feels your pain more than the developers and official testers.
My one comment to you is that it is actually worth the effort. The
radio is amazing.
Bob
N4HY
Mark Lunday wrote:
Thanks, Tim.
I installed the DPCLAT tool. I am seeing consistent 1000 micro-sec latency
on the DPCLAT tool. Oh, there are a few drops to 500 microseconds, and a
few spikes of 16000 microseconds or greater.
I have disabled everything I can think of in the Device manager, without
impairing the machine:
* Wireless network card (even tried the LAN card) - no change
* Tablet pen input
* Other USB controllers, except for the one with the mouse and the one with
the keyboard
* Internal computer sound card
* Any other human interface devices not in use
I also took a look at the services which are running. I cannot find any
which would still affect the machine. Antivirus is off...Vista search
indexer is off. I am running Windows Basic for display, not Aero glass for
Vista.
CPU shows about 11% utilization, 850MB out of 2 GB of memory in use.
Interesting test - when I unplug the firewire connection, the latency drops
WAY down, to about 50 microseconds...with only a spike of 1000 microseconds
every 5 seconds or so. As soon as the firewire cable goes back in, we go
back up to 1000 microseconds again. The driver is dated June 2006, that was
just before gold code of Vista came out. I checked (RICOH OHCI Compliant
IEEE 1394 Host Controller) and the installed version looks like the latest
one available:
http://www.pcpitstop.com/drivers/download/RICOH~OHCI~Compliant~IEEE~1394~Hos
t~Controller.html
So we have met the enemy which is causing the latency, and it is US. The
firewire connection is causing a latency which is affecting the performance
of the firewire connection. How about that! Talk about going in circles...
I don't suppose there is anything I can do at this point....
Mark Lunday
WD4ELG
wd4...@arrl.net
http://wd4elg.net
--
(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
"You don't need to see the whole staircase, just
take the first step.", MLK.
Twitter:rwmcgwier
Active: Facebook,Myspace,LinkedIn
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