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August 14 2017:VirtualBox, Node-RED, LyX, P versus NP and Firefox Meet

Posted on 2017-08-16 21:55:36 +0000 by John

As a result of questions by Ash at the previous meeting and John W at this one,

John H demonstrated VirtualBox with FreeDOS running inside it. He has yet to install any DOS programs to run in it!

He also showed the six lines needed to upgrade his system from openSUSE 42.2 to openSUSE 42.3 starting with tmux to deal with any breaks in connection during the upgrade and ending with init 6 to reboot:

tmux
cp -Rv /etc/zypp/repos.d /etc/zypp/repos.d.Old
sed -i 's/42\.2/42\.3/g' /etc/zypp/repos.d/*
zypper --gpg-auto-import-keys ref
zypper dup
init 6

Brian then gave a progress report on his project to turn a clock radio into an Internet clock radio using Node-RED beginning with a brief summary of the demonstration he had given in September 2016. So far he had been able to set up a Raspberry Pi to link to three Internet radio stations and generate an announcement of the station selected. He plans to implement it on a Raspberry Pi Zero.

This led into a discussion of the range of possible inputs which Node-RED can use including Twitter and Alice commented that that they were using Node-RED a lot at work to assemble various kinds of data.

John H then gave a quick summary of LyX, a GUI for LaTeX, the package system developed in the 1990s to support Donald Knuth’s typesetting program, TeX, and the later programs, XeTeX and LuaTeX, which add Unicode support which did not exist when Knuth wrote the original program.

LyX follows the Unix philosophy of not duplicating what already exists; so images are handled by ImageMagick and spellchecking by Hunspell using the LibreOffice dictionaries. So it mostly sends scripts for LaTeX packages and external programs to execute.

LaTeX offers easy handling of parts, chapters and sections, bibliographies, multicolumn support as well as a range of minipages, a range of text enhancements and manipulations, customised colours and image manipulation.

The LyX interface offers everything you would get in a word-processor but with a dynamic outliner allowing you to move whole sections around or look for particular footnotes or citations, integration with a version control system such as Git and an advanced search function which allows you to find and replace formatted input such as formulae.

It is not WYSIWYG but generates a PDF of the output for preview; it uses a tabbed interface which allows you to edit different parts of the same document simultaneously or to work on a translation with one language in one tab and another in the other.

However, John does not use it exclusively because export to Word formats is not straightforward. So he still uses LibreOffice for anything which needs exchanging in a Word format.

There is a general introduction to LyX on John’s website and information on some of the more sophisticated features in Tips, Tricks and Extended Features.

David then pointed to the news that there is a possible solution to the P versus NP problem which would have massive implications for cryptography which relies on there being no easy solutions to the P versus NP problem.

Alice drew attention to the changes in Firefox 57, scheduled for release in November 2017, which mean that older add-ons will no longer work, only WebExtensions. Even bigger changes are planned for Firefox 60.

David revealed that his talk at the NetBSD pkgsrc conference had largely been repeated at the Gnome conference by Emmanuele Bassi and had gone down like a lead balloon there!

John H drew attention to Brendan Gregg’s blog about Linux load averages and why they are different from any other OS.