Kyle Downey

Z800 mining rig ROI calculation

A computational home heating system

The replacement power supply -- the Z800's third one now -- arrived while we were on holiday, and so far seems to be running better. I decided to put it to the test by mining Dash and Ethereum in order to learn more about the mining process.

Running some numbers, one thing is clear: mining Dash at home with a GPU is a good way to . . .

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September 19, 2015

Dead PSU on the Z800

Reboot aborted

I decided to start over with a plain Debian install after wrestling with Solaris x86 and taking a break from coding at home. I hit the power button, which flashed briefly and then ... nothing, shut down. Reseated the PSU, and again no joy. Checked for bent pins or something dumb like a loose plug and all seemed fine.

The Z800 power . . .

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July 11, 2015


Low-latency messaging library

Martin Thompson's Strangeloop talk is worth watching for anyone interested in high-performance Java. Like Peter Lawrey's Chronicle Queue, Aeron's foundation is a low-latency append-only log, but even more ambitious. It is media-agnostic and --like ZeroMQ -- meant to be portable across languages, and he envisions supporting . . .

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February 28, 2015

SATA cable headaches

HP really doesn't want you to use a RAID card

The HP Z800 has four drive sleds accessible through the side panel. You can drop in a 3.5" drive and slide it in and it plugs into a SATA port at the back. These ports in turn go to four cables that can plug into the SAS or SATA ports on the bottom of the motherboard. Unfortunately the LSI controller in the Z800 is old and does not . . .

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February 21, 2015

Drone CI

(Not really) securing a local server with Nginx

Being able to build and test software with every change is very important, especially if the goal is to iterate and deliver into production constantly. As projects get bigger the chance that you will have an unnoticed regression gets higher, and so it's important to catch them while you still have fresh in your mind what changed recently. . . .

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February 16, 2015

Building Bitcoin Core

Beware of crypto bearing software patents

One of the things I want to do with the new server is run a Bitcoin full node. It doesn't compile on Solaris, so that meant setting up a Linux virtual machine first.

Since, sadly, the painfully hip Crunchbang Linux distribution is now no longer being maintained, I started by setting up Fedora Workstation 21 under VirtualBox. I . . .

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February 14, 2015

Solaris ZFS and the 2 TB Limit

Starting over with the new server

The two hard drive caddies arrived, and I installed the dual Seagate Barracuda 3 TB drives. Unfortunately the system BIOS did not recognize more than 2 TB, nor did Solaris or Fedora 21 Server.

Silvrback blog image

From Seagate Beyond 2TB site my understanding is on older BIOS the only way to make this work is with a special driver available . . .

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February 11, 2015