Dan Drown

ARM router forwarding rates

The goal for this project is 300mbit/s forwarding with full size packets and nat enabled. There's problems with this hardware: see "Problems" section below. test setup Router hardware: Utilite Standard [http://utilite-computer.com/web/utilite-models] (note: see the Problems section) Network eth0 - "inside&

mosh/Android build VM

To Download the VM image: docker pull ddrown/mosh-build To build mosh binaries: OUTPUTDIR=~/target mkdir $OUTPUTDIR docker run -v $OUTPUTDIR:/target ddrown/mosh-build This will create 6 binaries in $OUTPUTDIR/bin: mosh-client.arm.nopie, mosh-client.arm.pie, mosh-client.x86.nopie, mosh-client.x86.pie, mosh-client.mips.nopie, and mosh-client.mips.

Busybox/Android build VM

I took the Android Cross Compile VM [https://blog.dan.drown.org/android-cross-compile-environment/] and created a docker VM image for just building busybox. To Download the VM image: docker pull ddrown/busybox-build To build busybox binaries: OUTPUTDIR=~/target mkdir $OUTPUTDIR docker run -v $OUTPUTDIR:/target ddrown/busybox-build This will create

Updated busybox builds

I rebuilt busybox and upgraded to 1.22.1. The new Android L developer preview requires binaries built with PIE [http://en.wikipedia.org/wiki/Position-independent_code]. Android 4.1 is the oldest version that works with PIE binaries. This means two builds per CPU architecture are needed. Android 4.

Android Cross Compile environment

I took my Android ports build environment and turned it into a docker image. To download it (should be around 2.3GB), install docker on Linux and then run: # docker pull ddrown/android-cross-compile Pulling repository ddrown/android-cross-compile c9c1ce340d35: Download complete 511136ea3c5a: Download complete 34e94e67e63a: Download complete 0c752394b855: Download complete dea657cfb317:

Navspark NTP stratum 0 clock

Project Goal I want to create a stratum 0 NTP clock that does not require soldering or any special hardware. It should only require a USB port and software. It should have at least 125 microsecond accuracy. How? I created a Navspark firmware to print a timestamp on the serial

Navspark UART/USB bridge

I created a program on the Navspark to send characters at 150 microsecond intervals and then received them on a PC. Below is a histogram of how long it took between characters: The red boxes are how long it took for the UART/USB bridge to send one character in

Navspark timer drift, #2

Second run, this time comparing the Navspark's internal CPU clock against the GPS time. Samples of both clocks are taken once per second, and the amount of time that has passed is calculated for both. The ideal CPU clock would be a perfectly horizontal line at 0.000

Navspark timer drift

The Navspark is a microcontroller with a GPS peripheral. It runs the GPS navigation/timing code as a binary-only library, and uses the Arduino IDE/environment. I have custom code printing timestamp markers on the Navspark, and I'm measuring the timestamp of the first byte of each line

ARM-based router

This hardware has problems - see the Problems section [https://blog.dan.drown.org/arm-router-forwarding-rates/] on the follow-up page. I have an arm system with two gige ports that I want to turn into a router that can forward at least 300Mbit/s (with 1500 byte packets). It's