June 2015 - wlug - list.wlug.org.nz

GMT Versus UTC
by Lawrence D'Oliveiro 01 Jul '15

01 Jul '15

It still seems to be common among groups outside the computing and scientific worlds to talk about “GMT” rather than “UTC”. The trouble with “GMT” is that it doesn’t seem to be clearly defined; it might or might not differ from UTC by up to 0.9 seconds. The (unadjusted) time reference defined by an official collection of atomic clocks worldwide is called “TAI”. This pays no heed to the slowing rotation of the Earth. Astronomers prefer a time reference called “UT1”, which is based on the actual rotation of the Earth (subject to some time-averaging, I think). The definition of “UTC” comes from TAI, adjusted by applying leap seconds. These accumulate as needed so as to keep UTC within 0.9 seconds of UT1, and we are currently up to 36 of them. That is, at 0:00:00 UTC today, TAI was actually 0:00:36. The trouble with GMT is that it is not officially clear whether it is the same as UT1, or the same as UTC. Given that it was originally defined at the Greenwich Observatory, which was (is?) run by astronomers, one would think they would make it the same as UT1. But the practical fact is, our usual everyday timekeeping is based on standard time zones, which are all defined as whole-second (indeed, whole multiples of a half-hour) offsets from UTC.

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How Long Can A Filename Be?
by Lawrence D'Oliveiro 01 Jul '15

01 Jul '15

Allowed length of an individual file/directory name: ldo(a)theon:~> getconf NAME_MAX / 255 Allowed length of a full path name: ldo(a)theon:~> getconf PATH_MAX / 4096 The answers can be filesystem-specific; here “/” is an ext3 filesystem. But on my /home, which is ext4, I get the same numbers.

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Reuters: Samsung won’t give up on Tizen OS, plans more phones this year
by Peter Reutemann 01 Jul '15

01 Jul '15

'Samsung still loves its home-grown operating system. A report from Reuters says the company is planning more Tizen phones for 2015, and they'll come in at "varying prices."' -- source: http://arstechnica.com/gadgets/2015/06/reuters-samsung-wont-give-up-on-tize… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 858-5174 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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So How Did Your Leap-Second Go?
by Lawrence D'Oliveiro 01 Jul '15

01 Jul '15

At noon today NZ time, an extra second was inserted into UTC, the time kept by the world’s atomic clocks. The time that was one second before midnight UTC (one second before noon NZST) became two seconds before intead: after 23:59:59 UTC came 23:59:60 UTC, before ticking over to 0:00:00 UTC. The previous time this happened, three years ago, several Linux-based systems malfunctioned. No word yet on how this one went... <http://lwn.net/Articles/648313/>

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Doing For Video What PulseAudio Did For Audio
by Lawrence D'Oliveiro 01 Jul '15

01 Jul '15

Pinos is a project to allow better handling of video input across multiple applications. Pinos will make it easier to switch cameras in applications and for the same camera source to be used by multiple apps simultaneously, there will be support for multiple types of video inputs, GStreamer integration, and some audio support. Pinos should allow better screencasting within GNOME 3, video support for desktop sandboxes, and many other potential use-cases. In an email, Christian mentioned why it didn't end up being called PulseVideo over name squatting. <http://phoronix.com/scan.php?page=news_item&px=Fedora-Pinos-Announced>

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presentations/demos for next meeting
by Peter Reutemann 01 Jul '15

01 Jul '15

Hi everyone At the moment, we're still looking for a theme (read presenters) for this month's WLUG meeting on July 27. Any takers? As a fallback option, I was thinking of giving the new Linux Mint 17.2 a spin (MATE and Cinnamon) and Ian has plenty of Debian 8 installations on his machine to show off briefly. Thanks. Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 858-5174 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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How to upgrade Debian Wheezy to Jessie safely
by Peter Reutemann 01 Jul '15

01 Jul '15

"This tutorial explains how to upgrade your Debian system from Wheezy to Jessie in a few simple steps. Before you start with the upgrade, backup all critical data. Thats especially the config data in the /etc directory and the user data in /home. When you run a server then you should include the databases (MySQL, Postgresql, etc), web and email data in the backup as well." -- source: http://www.linuxtoday.com/infrastructure/how-to-upgrade-debian-wheezy-to-je… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 858-5174 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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SSH To Multiple Machines Simultaneously with DSH
by Peter Reutemann 01 Jul '15

01 Jul '15

"Once you grow beyond managing one or two servers, you???ll find yourself wasting a ton of time if you don't have a way to run commands on multiple Linux computers simultaneously. In this post, I'll explain how to quickly run commands on large numbers of Linux machines at once." -- source: http://www.linuxtoday.com/upload/ssh-to-multiple-machines-simultaneously-wi… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 858-5174 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Win XP lives OK!??
by Ian Young 26 Jun '15

26 Jun '15

Sorry this is utterly off-topic but couldn't resist. Stranger than fiction. http://www.theinquirer.net/inquirer/news/2414849/windows-xp-us-navy-throws-…

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MAC Address Privacy Standard Coming
by Lawrence D'Oliveiro 26 Jun '15

26 Jun '15

Every network interface (wired or wireless) on every networked device in the world is assigned a unique 48-bit identifier—the MAC address—burned into its ROM at manufacturing time. While it’s often (usually?) possible to change this via the software driver, nobody thought of it as a big deal. Until recently, when certain, ahem, spying revelations have woken people to the privacy implications of being able to track a machine, particularly on wi-fi networks, based on its unique MAC address. And so some folks at the Internet Engineering Task Force have been doing experiments to determine whether randomly changing these addresses would cause hiccups for any network protocols. The good news is that the answer so far seems to be “no”. <http://www.theregister.co.uk/2015/06/26/mac_address_privacy_inches_towards_…>

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