Dewalt DW411 vacuum adapter – 3D print

I have been doing some woodworking prvacAdapter_preview_featuredojects lately, and got tired with my palm sander constantly clogging with dust. The sander did have a vacuum adapter once, but must have fallen out of the transoceanic shipping container or something similar. Rather than trolling through ebay (Latgalīte!) or amazon for a used one, I drafted a replacement in SetchUp and printed up a new one. Nothing much, but it comes in handy. If someone else needs a copy, I have posted it in thingiverse for anyone who needs a copy.

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Improved iBolt xProDock Latch

About a year ago I ordered the iBolt xProDock for my Samsung Note3, and have been quite satisfied with it, except for one niggle – the latch holding the phone is spring loaded, and it is nearly impossible to attach or remove the phone from the dock single handed. With one hand you need to pull the spring loaded latch up, then with the other hand remove the phone. Last week, the latch finally broke. Rather than buy a new dock, I decided to improve upon the design. Continue reading

vCenter 5.5 web interface and the Cubic congestion algorithm

It has been a while since I last posted, but thought this one might be of interest to a few of you, especially since I keep running into it every so often.

Some time ago I did a performance analysis of multiple manufacturer NICs. As a part of that test, I also tested the impact of changing the TCP congestion algorithm in VMware from the default New Reno to Cubic. The cubic algorithm consistently delivered better throughput results in the tests, and since then I have updated all of our hosts to use this.

Unfortunately, if the algorithm is set via the VMware 5.5 vCenter Web Interface, not all of the required changes are applied properly to the target ESXi host and upon reboot, the host is unable to connect to vCenter. It took quite a bit of work with VMware until we discovered the root cause. Fortunately, we did identify a simple workaround, documented here:   Continue reading

ESXi 5.5 enable SSD

VMware’s ESXi servers frequently are unable to recognize attached SSD devices, especially when they are behind a RAID controller. If a storage device is not recognized as an SSD, it cannot be designated for vFRC or the Virtual Flash Host Swap Cache function. A set of commands outlined in VMware’s KB 2013188 will mark the storage device as a local SSD and enable the required functionality. If you are up to living dangerously, you can mark any local storage device as an SSD. Continue reading

VMware 10G NIC Performance Evaluation

For the last few years we have been running IBM x3850 x5 servers in our cloud, with Emulex 10G NICs for all of our networking needs. One of our services was starting to run out of steam, and we picked up a pair of HP DL580 G8 servers for the needed horsepower. These servers were configured with Intel based 10G NICs. At the time of the purchase, our main concern was to get the maximum CPU performance and minimal attention was paid to 10G NIC selection.

As we put these servers into production, we noticed that the VMware iSCSI performance on the new HP hosts seemed especially good. The E7-8891v2 Xeons undoubtedly have a large role to play in the improved performance, but we began to wonder how much of the performance improvement can be attributed to the 10G NICs. Not one to let such thoughts sit idle for long, I asked our friends at Zones if we can borrow a few 10G NICs for performance evaluation. Within a few weeks I had dual port Intel and Mellanox 10G NICs in hand for testing, in addition to the Emulex NICs already present in our IBM hosts. Continue reading

PWM Based LED Driver

** Updated code for better performance and stability [26 Feb 2015, rev.3]

It has been quite some time since my last post – as often happens, life intervenes and this time just a bit too much hospital time both for myself and one of my kids. Things are good now and normal can resume…

Black-Decker-FSL18FL-Firestorm-18-volt-FlashlightFor years I have had this Black&Decker FireStorm FSL18 flashlight, but hardly ever used it due to its anemic light quality. The fixture is powered with an 18v battery pack and uses a KPR18v0.3A bulb putting out 7 candlepower when running at 18 volts. 1 candlepower = 1 lumen. Compared with the brightness of the 12v power LEDs I have been working with lately, the brightness from this incandescent bulb is not much better than a glassed candle.

The trigger for upgrading this flashlight came one day when the wife complained an LED lightbulb had failed in her workshop. I replaced the bulb, but rather than throw it away, I took it down to my workshop to disassemble and identify what had broken. Continue reading