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Charles Steinkuehler
Worked at NewTek
Lives in Topeka, KS
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Charles Steinkuehler

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More Machinekit + ROS integration, this time with a BBB and CRAMPS running ROS client, with the moveit and RViz on a PC.
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Charles Steinkuehler

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You know you've picked up enterprise grade Ethernet hardware when you have to dig out a serial cable to perform the initial configuration. NO network-based administration is enabled by default!  :)
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+Charles Steinkuehler As usual I have equipment envy. I just purchased a GS510TP, GS108TP, and ERLite-3 for my home LAN. I'm looking into pulling new CAT6a F/UTP for future 10GBase-T equipment.
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Charles Steinkuehler

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Start making plans now!
 
Hey guys. The dates are set for next years MRRF ( or some name like it ). March 18-20th at the same location as last year. We're starting earlier in the planning this year. Basically, we're starting to figure out a wifi solution LOL

http://midwestreprapfest.org

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Charles Steinkuehler

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I cannot type faster than a 50+ year old mechanical typewriter (IBM Selectric).
I cannot type faster than a 30+ year old computer (Apple-II, IBM-PC, Amiga, many others).
WHY can I EASILY type faster than a modern eight-core multi-GHz computer?!?!?
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I have to agree. The Cubs making it to the playoff and winning their first game is a sign of the apocalypse.
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Charles Steinkuehler

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Nailed it!
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ROS driving a stepper motor via Machinekit (and a BeagleBone + BeBoPr).  Physical hardware in the upper-left, ROS simulation on the right, and HALScope showing the drive signal on the left.

The ROS JointTrajectory messages are sent to a HAL component via a ring-buffer and interpolated to 1 mS position samples.
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Charles Steinkuehler

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I've had my iSCSI SAN running for a while, but still haven't gotten decent performance.  No matter what setting I tweaked, I couldn't get any better than about 450 MBits/s per link, even when testing with utilities like iperf.  No issues with CPU load, IRQ balancing, or anything to indicate either end of the SAN was hitting it's limits.

 Finally I found a link suggesting I look at low-level stats via "ethtool -S".  Turns out both ends of my SAN had received a lot of rx_flow_control messages from the other end, but neither had sent any tx_flow_control messages.  So if the problem isn't either end, it must be in the middle!

I swapped the Netgear GS724T for an HP Procurve 2824 and speeds instantly jumped to full wire-line speed!  Only the 2824 doesn't support both jumbo frames and flow control on the same port, so now I need to find the cheapest quality switch that will.  And yes, you do want flow control on your SAN switch...iSCSI gets seriously confused when you start dropping packets.  :)
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When you've got fancy 4-pin speed-controlled fans in your 24-drive server chassis, but you're doing CPU/memory load testing so they all run full speed anyway.  Even with earplugs it's LOUD!  And if you need a good stability test utility, I suggest "breakin" vix PXE boot: http://www.advancedclustering.com/products/software/breakin/
Breakin is Advanced Clustering's free open-source stress-test and hardware diagnostics tool. Tests: CPU, RAM, and disk while reporting Temps and ECC errors
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With the demise of Coraid, I decided to bite the bullet and switch over to an iSCSI SAN by installing Linux on my shelf-spare SR2461 (a standard SuperMicro server platform with a Coraid custom Plan9 OS on a flash drive).  I got it working, but <GAK!> how did iSCSI win out over AoE?  The only thing I can think of is the painful configuration (which is even worse for multi-path) creates job security and lock-in for the SAN vendors.  <meh>
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Nov 6-8/2015, Madison WI We are please to invite anyone interested to the second "real world" Machinekit meeting, taking place on November 6/8 at the Tormach facility in Madison, Wisconsin (USA).  Please feel free to join us...
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In his circles
101 people
Have him in circles
331 people
Kevin Warner's profile photo
Brendan Moran's profile photo
Dreux Doty's profile photo
Andrew Wade's profile photo
Stuart Mitchell's profile photo
3DLT.com's profile photo
Steve Graber's profile photo
JaeHyung Lee's profile photo
Logic Supply's profile photo
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