[Technology] Working in parallel

I have about 704 .flac music files that I want to convert to .ogg.  Mostly because flac is a lossless encoding while ogg is lossy, so for a potentially imperceptible reduction in audio quality, I reduce disk usage for these files by ~75%.  Hooray.

I noticed oggenc doesn't seem to make good use of my quadcore processor, so I used find + head + tail to split the collection into 4 sets that are being re-encoded in their own terminals.  Each process is using 70-80%, with gnome-shell stealing the other cycles (GNOME Shell tends to run ~90% when I have my second monitor attached).

Hooray.  Once they're in ogg, I'll have an easier time sharing them with my tablet.  Speaking of which, it's a bit sad that it's faster to copy music files to a USB key and then copy them from there to the tablet then to just copy them over wifi.  Hehe.  (~1MB/s over wifi versus ~15MB/s to the USB (but gets copied twice, for an average of 7.5MB/s)).

[Technology] Building Synergy

Synergy is software that will share a keyboard, mouse, and clipboard between computers over a network.  It's great.  If you have multiple machines in one place, you can just drag your mouse cursor between their screens, even if they're running different operating system.

I want to start off by saying that synergy seems like great software.  I used it a lot in the past, and was very pleased with the results.  It wasn't very user friendly then, and at some point it was no longer actively maintained.  It seems to be actively maintained now, and even has file drag-and-drop support between computers (for Windows and Mac, not for Linux yet ;_;).  In the rest of this post, I'll be detailing each step and obstacle I encountered trying to set up synergy 1.4.16 (the latest as of today) on Fedora 20.  In part, I hope it helps the next person who tries this and perhaps Googles their error messages.  Know that if you're just a regular user, don't take the issues that arise below as a cause for terror.  You can do what you should, just install the package from the repository (if you're fine not having your key presses be encrypted over the network...) and not worry about anything.  A lot of the problems below will emerge from me not properly understanding what's expected, but then that goes to show how straightforward or not building Synergy can be.

A quick summary is:

  • can't install from RPM

  • can't build from source using cmake

  • can't install from source using configure

  • just copied binaries out of RPM in the end :(

attempt 1: installing from an RPM

I run Fedora Linux 20.  The version Fedora has in its repository is 1.4.10.  The latest version from synergy-foss.org is 1.4.16 and has some features I would like.  synergy-foss.org provides a pre-built package for Fedora, but there's an issue with their package for 1.4.16 preventing it from installing.

Error: Package: synergy-1.4.16-1.x86_64 (/synergy-1.4.16-r1969-Linux-x86_64)
           Requires: libcurl.so.4(CURL_OPENSSL_3)(64bit)

They explain that in their release notes.  Basically the packages get built on a Ubuntu installation which has an out-dated version of curl.  Whoops.  So, I'll take the opportunity to build it myself.

attempt 2: building from source, with cmake (their recommendation)

The first problem I have in building is that their wiki tells me to use their hm script.  First, I try following hm.sh's own suggestion of

$ ./hm.sh build -g 1

Error: option -g not recognized

Hmm, double check the wiki and ... aha, yes, apparently -g should go to conf and not build.  When I try doing

$ ./hm.sh conf -g1
Error: Could not find qmake.
Error: Cannot continue without qmake. 

Fine.  I install qt-devel, and set PATH to include the directory containing qmake

PATH=$PATH:/usr/lib64/qt4/bin ./hm.sh conf -g1

Success.  Next step,

$ ./hm.sh build
Entering dir: build/release
make: *** No targets specified and no makefile found.  Stop.

... Great. The instructions say I can skip the hm script, so yay.  I follow its advice and go to

$ cd build/

$ make
make: *** No targets specified and no makefile found.  Stop.

attempt 3: building from source, the old fashioned way (not their recommendation)

... Alright.  I see that there is a configure script.  I am used to doing ./configure && make && make install, so let's try it the old fashioned way. The next problem I encounter is with Xtst,

Missing library: Xtst

I thus installed libXtst-devel (which may have been unnecessary; libXtst was already installed) but still, I get that error message.  I then grep'd about and checked CMakeError.log.

/usr/bin/cc   -DCHECK_FUNCTION_EXISTS=XTestQueryExtension    CMakeFiles/cmTryCompileExec218679776.dir/CheckFunctionExists.c.o  -o cmTr\
yCompileExec218679776 -rdynamic -lXtst -lXext -lX11
/usr/bin/ld: cannot find -lXtst


I then went to /tmp/ and tried compiling with -lXtst myself and... it worked.

I deleted the build directory, and unpacked a new one, and ... it worked.  Annoyingly, their configure script apparently doesn't check again, and I'm not sure what you would use to clear its memory of the failure. Ah well.

Next problem is this:

CMake Error at tools/CMakeLists.txt:87 (add_library):
  Cannot find source file:

I poked about with find and grep and ultimately found tools/cryptopp562.zip.  If I just use unzip on it, it actually dumps all its files into the tools/ directory, so, clean up that mess, and then create cryptopp562, and unzip it into there.

And ... it works.  I think.  I manage to success do "make", but then there's no "make install" target.  Hmm, let's check hm.sh again; yup, there's an install target!

$ ./hm.sh install

Not yet implemented: install


I peeked in bin/ and found a bunch of binaries that are familiar to me from the old synergy/synergy2 days, but reading the User Manual and the User Wiki to find out how to set it up again almost exclusively references a GUI, and none of these binaries are a GUI...

attempt 4: pillaging the RPM

OK, let's just extract the contents of the 1.4.16 RPM and see how the .desktop application file works and- aha, there is another binary, synergy, that hasn't been built.  Let's just copy these into ~/.local/bin and ... it works.

It works.

running it

Now, getting it to run.  Two more hiccoughs.  One was that I needed to open the firewall port.  Using FirewallD in Fedora, I used this command,

firewall-cmd --add-port=24800/tcp

Next, I configured the server to know the client using the GUI, and they could finally connect.  Hurrah! 

It's running beautifully now.  Hopefully future releases will Just Work on Fedora like older releases. :)


[Technology] Trackpad only scrolling

So I've run into a problem on my Lenovo Thinkpad Twist occasionally where my trackpad starts only scrolling, as though for every touch it senses two fingers (if I disable two finger scroll then the trackpad stops responding all together).  Googling had advice such as "modprobe -r psmouse; modprobe psmouse" which doesn't work on my Fedora install since psmouse is built-in.  Some people suggest using the hardware key for disabling and re-enabling your trackpad.  My Thinkpad Twist does not have such a key.  So, I ended up using xinput.

# find out the ID of my trackpad

$ xinput list    

# Ah, it's 12!  Then disable and re-enable it

$ xinput disable 12

$ xinput enable 12

Hooray, my trackpad works again.  Well, works as well as it ever did.  It's kind of hysterical on the Lenovo Thinkpad Twist.  If only I had the leisure to debug the actual problem. :)


[General] Wanted: A personal information database

Update: and then I discovered dokuwiki


I want to be able to to

What I'd like right now

  • personal wiki

  • accessible remotely (but securely)

  • accessible via my mobile device

  • WYSIWYG, with inline images, tables

  • searchable, tags

  • open source

  • nice, standardised data representation (OrgMode, Latex, HTML); something easy and clean to parse

I think Microsoft OneNote offers some (if not all) of this.  I sort of want an experience that merges using Wikipedia and Aloha Editor.

Things that exist that are inadequate:

  • MediaWiki: big, requires web infrastructure (well, Apache), not WYSIWYG; comprehensive though

  • Tomboy: doesn't have inline images or tables; nicely WYSIWYG though

  • TiddlyWiki: doesn't save automatically, or have WYSIWYG; easy to setup though

  • org-mode in emacs: no WYSIWYG, no obvious remote; great data representation

  • MS OneNote: not open source, doesn't run on Linux; seems featureful


[General] Website Changes

Not very user visible, but I am now managing my website with git, as per these instructions.  That should eliminate issues I have with synchronisation.

Dieses Blog durchsuchen


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