Tag: Computing

Some tips when copying, recovering disks

Sunday, Mar 14, 2021

I seem to have a lot of suggestions to share with friends about managing disks on a linux livecd. Here are some of the tips I’d like to share. See the table of contents above for a breakdown of the topics discussed. Some disk related topics are out of scope for this article, as they deserve their own blog post. The topics not covered include partitioning, setting up a boot loader, using LVM2 or ZFS, that sort of thing.

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You want sudo -i or su -

Sunday, Feb 14, 2021

You want to use sudo -i or su - to log into root. sudo su anything is superfluous, because you probably should be using sudo -i or sudo -s, which are roughly equivalent, depending if you want to simulate a login (su - or sudo -i) or not (su or sudo -s).1 When to use su -? You want to log into root using the root password. Typically you must be in the wheel group (check your PAM configuration).

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About my keyboard choices

Tuesday, Nov 3, 2020

Disclaimer: Dvorak, fancy keyboards, whatever, does not replace good lifestyle habits such as computer breaks, good desk ergonomics, and balancing one’s computer life with gasp real life. Dvorak and fancy keyboards can make your life better, but they cannot completely address RSI problems alone. Since sometime 2013 I have faced pain, numbness, and tightness in my hands due to computer overuse. At first I chose to ignore it, but it got so bad I’d take days if not weeks off from prolonged computer use.

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Linux dmesg –follow (-w) not working?

Thursday, Apr 30, 2020

For a couple months now, I have noticed that running dmesg -w on my workstation does not appear to print out new kernel messages. In other words dmesg --follow “hangs”. Additionally when running tail -f /var/log/kern.log to monitor new dmesg messages picked up by sysklogd (part of syslogng), the latest messages do not come through until sysklogd periodically “reopens” the /dev/kmsg kernel message buffer. Why is this a problem? This is a problem because I use the dmesg log to monitor important hardware related messages such as the kernel recognizing a USB device or diagnosing bluetooth/wifi issues.

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Debugging Zathura, GTK (don't forget about seccomp)

Friday, Apr 24, 2020

Zathura is a fantastic PDF viewer. It also supports Postscript, DjVu, and Comicbook archive. In particular it supports using mupdf for the backend, so it’s rather fast (unlike poppler, used by evince and friends). Here is a screenshot of Zathura: Figure 1: screenshot of zathura Now that I’ve introduced Zathura. I want to talk about a problem I had recently. I wanted to print a document a couple weeks ago, but found whenever I issued a :print command in Zathura, the program would crash.

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A week in the life of Winston

Saturday, Apr 18, 2020

During these interesting times, I figure it would be a good idea to describe how I’ve been keeping myself busy, bugs I’ve fixed, and some of the daily tasks/routines that keep my day structured. For context: I moved house on the weekend of March 21st, which is a couple weeks before the Covid-19 fiasco became a front-and-center concern for my geographical region. I am finishing my undergrad in computer science — this is my last semester.

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Extending a wireless LAN with a bridged Ethernet LAN using Mikrotik RouterOS

Sunday, Mar 29, 2020

I recently moved, and my new abode has an Ubiquiti Amplifi LAN. The rationale is this mesh-based WiFi network eliminates the need to install Ethernet between Wireless Access Points (APs). It works surprisingly well. In this post I document how I extended this network so I could place my networked devices all on the same Ethernet segment, without needing to wire it to the Amplifi base station. The idea is the network should look like this:

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