Roland Turner

Yahi Haze Mapping
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Simplest Possible Systemd Service

(Because almost every search result for this provides a lengthy discussion instead of a simple example...) In /etc/systemd/system/sleep-92951829.service : [Unit] Description=Sleep Demo [Service] ExecStart=/bin/sleep 92951829 [Install] $ sudo chown root.root /etc/systemd/system/sleep-92951829.service $ sudo chmod 644 /etc/systemd/system/sleep-92951829.service $ sudo systemctl enable sleep-92951829 $ sudo systemctl start sleep-92951829 $ ps -fC sleep (more)

PayPal problem VV44REXSG (KMM201394745V73460L0KM) and the lack of a Singapore remittance license

3 years ago, PayPal ceased handling payments from Singapore account holders to charities outside of Singapore. The cited reason is that PayPal does not hold a remittance license in Singapore. An important consequence of this is that payments from Singaporean PayPal accounts to any non-profit organisation outside of Singapore, charitable or otherwise, are prevented. Inconveniently, and despite the fact that this is not a secret at all, PayPal appears unwilling to correctly describe the reason... (more)

First successful satellite tracker test

(Photo: Darryl Ee 9V1DE) After successfully listening to FO-29 with a handheld satellite-antenna at Geekcamp last year, I realised two things: directional antennas are extremely desirable for satellite work, but holding and pointing the antenna array by hand is exhausting. I therefore decided to build a tracker that would automate the pointing and following work. The resulting system came together just in time for Maker Faire, so I conducted its first tests on site. It... (more)

Peering inside TLS traffic, server-side

In the easy case where I have access to the server and am able to tell the client to use a different TCP port: socat TCP4-LISTEN:7080,fork,reuseaddr OPENSSL:localhost:443,verify=0 & socat OPENSSL-LISTEN:7443,certificate={certfile},key={keyfile},fork,reuseaddr,verify=0 TCP4:localhost:7080 & iptables -I INPUT -p TCP --dport 7443 -j ACCEPT Some details: Verification is unnecessary when talking to localhost, although this could be readily tightened with a sutable cafile option. Using verify=0 in the OPENSSL-LISTEN section was an unexpected necessity; without it socat requires... (more)

gtk-creator-usb "Failed to install the bootloader"

Old-school solution: dd if=ubuntu-{version}.iso of=/dev/{device} After several failures and various blind alleys around disabling automounting, I discovered this comment which happens to describe exactly my sitaution (creating a 64-bit installer on a 32-bit platform): Right, this explodes because the architecture you're running on doesn't allow starting executables of the architecture you're trying to burn on the USB disk. Everything is obvious in retrospect... (more)

Installing yum-cron

From the school of "the purpose of installing packages is to clutter your filesystem with files that don't do anything" comes yum-cron. Why anyone would want this installed but not working is not clear to me, but: yum install -y yum-cron service yum-cron status | grep -q enabled || service yum-cron start chkconfig yum-cron on (more)

Java Modifier Sequence

It's a trivial aesthetic thing, but the preferred sequence for "modifiers" is: public protected private static abstract final native synchronized transient volatile strictfp (more)

Importance of the LIGO results

The world's first "gravity receivers". There is much else to write about this, but I wrote the following in response to a friend's question about the importance of the discovery and felt it worth sharing: I get that observing gravitational waves is a big deal. But can someone enlighten me on how this new observation is going to make anyone's life better??? #‎WhyImInPublicHealth‬ It is an increment in a >6-century-long process of replacing ignorance and... (more)

A Conversation with a Lamp Post

Dramatis Personae Venue #HackerspaceSG a lamp post Roland not a lamp post Setting An SMS conversation at 8514 8312 ROLAND Hello venue #HackerspaceSG HACKERSPACESG Good morning. Thanks for waking me up, you're the first person I've spoken to. How would you use technology to make Singapore a better place? ROLAND Automate all work performed by foreign labourers. HACKERSPACESG I see. Someone told a friend "I would use technology to message and that makes singaporean a... (more)