Math-Intensive Reports with GNU Emacs and Calc, Part 1
Notice that my example kept track of units. It's able to do so because Calc also can perform symbolic algebra (a subject far too large for this small article) and treats the symbol "in" (inches) as an undetermined factor. Special operations are available to convert units. Calc knows about units and their conversion. For example, how many pints does a lake having 11,000 acre-feet of water contain? To find out, I first write out the volume in the given units:
$ WaterVolume := 11000. acre ft $
Now, if I type the expression WaterVolume => and evaluate it, I get this:
$ WaterVolume => 11000. acre ft $
Exactly what I typed in. Next, by putting the cursor over the acre unit, selecting (with j s and <codej m commands) the units expression (11000. acre ft) and invoking u c (units-convert), Calc will ask me what type of unit should be used in the conversion. I respond pt. Then Calc immediately changes the previous expression to this:
$ WaterVolume => 28674925714.3 pt $
Obviously, Calc knows how to convert an acre-foot to pints, and doing so is much quicker than describing it.
You don't have to use units at all if you don't want to. If you carefully define all your units up front and use them consistently throughout your report, Calc won't have to do any units munging. But it is useful for converting weird commercial units; it can be handy for converting, say, gas pipeline flow rates in MMSCFD into pounds mass per second.
More examples of Emacs/Calc magic will be presented in Part 2 of this article.
General description: www.gnu.org/software/software.html
FTP mirror list & instructions for downloading: www.gnu.org/order/ftp.html
Emacs Wiki: www.emacswiki.org/cgi-bin/wiki.pl
The Emacs Lisp Archive: archive.cis.ohio-state.edu/pub/emacs-lisp
The Emacs Lisp List: thalamus.wustl.edu/wonglab/stephen/ell/ell.html
Download code and documentation: mirrors.sunsite.dk/auctex/www/auctex
Download code and documentation: www.octave.org
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
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