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LinuxCNC latency and jitter improvements with PREEMPT_RT kernel parameter tuning
Introduction LinuxCNC control threads can be quite sensitive to system latency and jitter depending on the hardware control interface being used. Because of this, the installation ships with the so called PREEMPT_RT version of the Linux kernel. While this already boasts a huge improvement over the regular PREEMPT_DYNAMIC kernel there are many ... Read More
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The beauty of GPS disciplined oscillators (GPSDO)
Introduction GPS disciplined oscillators (GPSDO) can be used to create synchronized (coherent) clocks at a distance without drastically affecting other parameters of the local oscillator such as phase noise while simultaneously reducing long time drift. This article serves as an introduction into the underlying concepts to provide the backgrou... Read More
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The RF Performance of the General Radio GR874 Connector
Introduction The GR874 RF connector was conceptualized between 1947 and 1948 by General Radio being popular throughout 1950 up until 1970 for many different pieces of RF equipment. The hermafrodite design as well as its low reflection coefficients and relatively operating frequency (up to 10 GHz) allowed for its popularization. However, its lar... Read More
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How to make daily driving the Purism Librem5 work
Introduction The Purism Librem5 one of the first phones specifically designed to run Linux based operating systems without Android (along with the Pinephone). Stylistic render of the Purism Librem5 - CC-by-SA https://puri.sm As with any early concepts, designs and platforms this device has numerous small grievances which might complicate its... Read More
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Hameg hm1005 analog oscilloscope repair
Introduction Years ago I received an Hameg HM1005 analog oscilloscope. These scopes, much like any Hameg really, is easily recognizable by its easy to understand user interface. Unique to this Hameg scope is its combination of analog and digital features. Most prominently its three 100MHz bandwidth inputs, x times y mode and 10x horizontal zoom... Read More
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Background on OpenCSD and FluffleFS
Modern storage servers are faced with an ever increasing gap in bandwidth offered by NVMe flash storage devices and what can be moved to main system memory. Due to the Von Nuemann architecture all data needs to be moved to this main system memory before it can be processed. Computational Storage Devices (CSx)s aim to resolve this bottleneck by o... Read More
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RISC-V RV32I assembly with Ripes simulator
Assembly is the closest resembling programming language to pure machine code instructions. The available instructions depend on the architecture and even supported extensions. In this tutorial the available instructions will be limited to the most basic set of RISC-V instructions. This set of instructions is denoted as RV32I meaning that it enta... Read More
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Getting started with RISC-V
So you have heard of this RISC-V thing typically talked about in the context of microprocessors and to a lesser degree also for desktop processors. RISC-V is an open-source hardware instruction set architecture (ISA). Similarly to how X86 for Intel and AMD is a closed source ISA. Being an open-source ISA any manufacturer can develop new processo... Read More
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Dynamically adding models to sqlalchemy declarative_base
This is a Python tutorial showing how models can dynamically be added to an instance of declarative_base without triggering pep8 unused import. This example works best if the project uses a directory structure similar to the following (__init__.py has been omitted): database database_manager.py models exam... Read More
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Installing Ubuntu on Acer Spin UEFI devices
Installing Ubuntu on the Acer Spin 1 has been proving to be quite the hassle to me. Fortunately; following these steps allows other to easily install Ubuntu on the Acer Spin 1 and possible many other Acer UEFI devices. Installing the bootloader will likely fail steps are provided to recover from this and perform bootloader repair. Steps install... Read More
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xrandr – Treat Multiple Monitors as Single Screen
Many window managers such as xfce, gnome or kde have graphical utilities to help configure a multi monitor setup. However, almost none if any support configuring multiple monitors as a single screen. In the past technologies such as AMD eyefinity or Nvidia Mosaic enabled these features but they are vendor specific. Problems around Linux compatib... Read More