The ARM Arc Part 3

The ARM Arc Part 3


This week heralded the announcement of Red Hat Enterprise Linux Server for ARM Development Preview 7.1, the next milestone in Red Hat’s exploring the potential for ARM servers.  There is a lot in a name, and this one is a mouthful.

The Linux kernel is famous – it is the namesake of the complete operating system, but it does not exist on its own.  A complete OS runs on hardware, starts out in firmware, loads the kernel, which in turn loads a software and service initialization system, all of which require function libraries, all of which were built with compiler tools that do the magic conversion from human readable source code to machine readable binaries.  When ARM designed the AArch64 architecture, they also had to provide ports and specifications for the firmware, the kernel, the libraries, the compiler, and so on. Hundreds of packages were affected.  Not only did they need to provide ports, those ports needed to be designed, written correctly, in a style acceptable to each of the communities whose coding standards are frequently rigorous, distinct, and strictly enforced.  To top it all off, this work needed to be done before the actual hardware existed, necessitating writing software simulators to check all the work and extensive documentation to empower community collaboration.

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Five different ways to handle leap seconds with NTP

A leap second is an adjustment that is once in a while applied to the Coordinated Universal Time (UTC) to keep it close to the mean solar time. The concept is similar to that of leap day, but instead of adding a 29th day to February to keep the calendar synchronized with Earth’s orbit around the Sun, an extra second 23:59:60 is added to the last day of June or December to keep the time of the day synchronized with the Earth’s rotation relative to the Sun. The mean solar day is about 2 milliseconds longer than 24 hours and in long term it’s getting longer as the Moon is constantly slowing down the Earth’s rotation.

UTC is based on the International Atomic Time (TAI) and it is currently 35 seconds behind TAI. The first leap second was inserted in 1972 and 25 seconds were inserted so far. The next one is scheduled for 30 June 2015, when the offset from TAI will increase to 36 seconds. Leap seconds are scheduled only about 6 months in advance.

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The ARM Arc Part 2

This is a continuation to The ARM Arc Part 1 published in July.

ARM_LogoIt all started in 2012 when the Fedora ARM community decided to move from the legacy ARMv5 software floating point ABI to the new ARMv7 hard float ABI.  The move meant better performing code, native atomic operations, threading support, and other modern OS features becoming available to ARM software developers on a general purpose OS.  Doing the work required a way to bootstrap a new architecture, which is notoriously difficult due to Fedora’s inter-dependent package structure.  When building package A depends on having package B, and building package B depends on having package A, and you have 15000 such packages, it poses an epic challenge.

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The ARM Arc

ARM.  When used in a sentence it may refer to the company (ARM Holdings), one of its numerous CPU versions, or even a way of life.  But we just call it ARM.  ARM (the company) creates low power processor designs which they license to other companies to implement; Licensees enhance ARM’s design and manufacture the actual chips.  The resulting processors are the defacto standard in the fiercely competitive consumer mobile space of tablets and cell phones.  Of course, the thing that makes ARM interesting to Red Hat isn’t consumer mobile, it is evaluating their potential in servers.  In theory if they perform well, their low-wattage designs might be quite compelling.

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Red Hatters to Find at Fedora Flock – Prague, 6-9 August

Flock 2014 (Editor’s correction:  Flock is a “new, larger and pre-scheduled conference” for North America and Europe) is just a few weeks away and will be hosted in Prague, Czech Republic.
The entire list of sessions can be seen here, but below is the list of the 39 sessions delivered by Red Hatters.  Have a great conference!

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An Introduction to COPRs

As many of you have probably experienced, creating your own rpms can be handy, but what is even better is if you can access those rpms from anywhere on the internet. It is also handy to be able to share the rpms with your friends :). In the past that has meant building all of the rpms for the various RHEL-ecosystem OSs and then finding somewhere you can host them and maintaining it yourself.

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