CentOS 5 follow-up II

I was able to build gtkpod on CentOS 5 today. Wasn't all that hard, really. Leave a comment if you'd like the SRPM. (For some context, you may want to see my previous posts on gtkpod and CentOS 5.)

And yesterday when I ran yum, I found out why there's no xpdf in CentOS 5: it's been obsoleted by a package called poppler-utils. poppler is an xpdf fork, and the poppler-utils package includes the extra utilities like pdftotext and pdfimages. Apparently evince uses the poppler libraries. And if you prefer xpdf to evince (like I do), just compile xpdf (using the --with-freetype2-includes=/usr/include/freetype2 option to 'configure') and copy it into your path.

stupid bash tricks

Saw this on digg or something last week (and a friend also sent it to me via del.icio.us):

10 Linux Shell Tricks You Don’t Already Know. Really, we swear

I usually don't find these posts very useful, but this one had a couple of nice surprises. I'd never heard of ssh-copy-id, but it sure looks a lot easier than adding pubkeys manually. And the trick of recovering from an NFS mount gone haywire might work for a Samba mount (that happened to me the other day).

Recent energy-related developments

The San Francisco Chronicle has an article about how the idiots we elected to Congress are bickering about energy standards. Sometimes I'm amazed Congress ever gets anything done at all.

In happier news, the Energy Blog has a post about a new CO2 sequestration technique developed by Global Research Technologies (GRT). CO2 sequestration is the process of putting CO2 into storage (typically underground), instead of releasing it into the atmosphere: for example, future coal-burning power plants would point their smokestacks down, rather than up (that is a gross oversimplification).

But this GRT technique is a little different: instead of grabbing CO2 as it is produced (which I suppose can only level off greenhouse gas emissions), this method would be able to pull CO2 out of thin air (which could potentially reduce atmospheric greenhouse gases).

There is mention of the GRT technique on the wikipedia page for the Virgin Earth Challenge, Richard Branson's $25 million prize for atmospheric scrubbing of greenhouse gases.

The customer is always right

A fun post found its way to the digg homepage the other day. Although it was written by a Web designer, it's a pretty accurate indictment of the sort of thing I put up with, too:

If Architects Had To Work Like Web Designers

In a similar vein, StumbleUpon (installed it a few days ago--pretty cool) gave me this little bit of wisdom:

http://www.linuxkungfu.org/images/fun/geek/project.jpg

ODF v. OOXML

ONLamp has a pretty good article about the differences between ODF and OOXML. ODF (Open Document Format) and OOXML (Office Open XML) are both XML-based file formats which can be used to store word-processing documents, spreadsheets, etc. There is fierce competition for adoption between these two formats, notably in the arena of long-term government document storage. This competition is controversial for a number of reasons, including the fact that OOXML is a Microsoft product.

A google search for 'OOXML "men in black"' turns up quite a few hits regarding allegations of Microsoft lobbyists and lawyers trying to sway state legistatures (like Florida) toward OOXML.

Microsoft Protection Rackets

There's an interesting linuxtoday.com article about some of the recent patent indemnification deals Microsoft has signed (Novell, Xandros, Linspire, and LG). Actually, it's more about the companies who've gone on record saying they'll have no part of it (Red Hat, Canonical [Ubuntu], and Mandriva).

easytag

On a recent episode (#51) of The Linux Action Show (a weekly podcast about Linux), one of the hosts (Chris) was responding to a listener question about editing ID3 tags (that's the metadata attached to media files, like MP3 and OGG files).

This is interesting to me, because I've had sort of mixed results in editing ID3 tags (I've yammered about this before). I've tried the ID3-editing feature in gtkpod, but it consistently crashes gtkpod (ick). So I've been using the command-line utilities from id3lib. That works, but it's a command-line interface, and it's typically a file-at-a-time kind of thing.

Chris suggested easytag, and it's really cool. It's a graphical interface, and it makes it easy to edit the ID3 tags of multiple media files. There are RPMs for CentOS (v4 and v5) on the extras site. Good stuff. Thanks, Chris.

Shoutout to PJ

In support of PJ, I'm including the following inaccurate statements from a TechNewsWorld article by Kimberly Hill. Perhaps this will draw a few search engine hits. If you are reading this, please read PJ's side of the story, in which she (PJ) makes it clear that she had no part in the OSRM study about patents supposedly infringed by Linux: this is in direct contradiction to comments made by Laura Didio of the Yankee Group.

Here are some of the statements PJ refutes:

Back in 2004, said DiDio, then-fledging insurance firm Open Source Risk Management commissioned a study to determine just how many patients Linux may infringe upon. At that time, the number was pinned at 280 or so, most of them owned by IBM (NYSE: IBM) Latest News about IBM, with about 30 held by Microsoft.

The now-infamous study was performed by Pamela Jones of Groklaw, and its methods and conflicts have seen much comment since then. Still, DiDio asserted, the open source community itself was the first to raise the issue of how much Linux actually overlapped, in terms of intellectual property, with proprietary software.

zap2it closing

In December I bemoaned the revolting changes to yahoo's TV listings, and I switched to zap2it. Well, the other day I read that zap2it will be discontinuing its free TV listings on 1 September.

So it was looking like I'd have to find another source of online TV listings. But I just had a pleasant surprise. It looks like yahoo actually listened to (at least some of) the negative feedback from late last year, and their online TV listings don't suck nearly as much as the last time I wrote about them. At the time, I had three major gripes about the changes to yahoo TV:

1. painfully slow incremental loading--it doesn't do that any more
2. really annoying 3-hour browsing blocks--they're back to 1-hour increments (and they fixed the problem of not being able to see listings of shows starting prior to the current block)
3. amnesia about my display preferences: I signed in, set my preferences, signed out, deleted my cookies, signed back in, and it remembered to show just my favorite channels.

So, screw you, zap2it. And yahoo, you get another chance.

xpdf

Yesterday at work I got stuck retyping a handful of PDF files. They were nothing too fancy: black text in a garden-variety font on a white background, with a logo (image) in the upper-right corner. Nothing I couldn't do in a word processor, but I didn't want to retype all that junk (I have no idea what became of the original documents--I just had the PDFs).

xpdf was a big help to me. xpdf is an open-source PDF viewer, and it comes with several command-line programs. Yesterday I was able to use two of these programs to help me recreate the documents: pdfimages extracted the logo image (in ppm format) from one of the PDFs, and pdftotext converted each PDF file to text. So I was able to use oowriter (the word processor of openoffice.org) to create the new documents, and I could just copy-and-paste from the text files generated by pdftotext. Still tedious and annoying, but better than typing from scratch (less error-prone, too).

CentOS 5 doesn't have xpdf. This experience highlighted to me how important that package is to me (I use xpdf to view PDFs all the time). So I spent some time this morning building xpdf on CentOS 5 from source, and I came up with an SRPM. I sent it to the CentOS Extras site--maybe they'll add it to their package list. If you want the spec file, leave a comment.

Tiki Bar

If you find yourself with some free time, try out Tiki Bar. Very funny, and a good excuse to drink. (They also have an RSS feed.)

Middle-click on a laptop

Lately I've been using my laptop without a mouse (actually on my lap, rather than on a table where there's room for a mouse). My laptop has a touchpad with two buttons. I've enabled Emulate3Buttons in X11 so that I can click both buttons at the same time to simulate a middle-click. This is useful to me, because I use middle-click a lot for pasting (highlighting some text is an implicit 'copy', and a middle-click pastes at the cursor location).

The problem is that I find it difficult to click both buttons at the same time. I usually end up clicking one or the other, which typically throws off the focus and undoes the 'copy' (so the stuff I want to paste is no longer in the X11 clipboard).

(Yes, this is exactly the sort of thing that drives me insane.)

The other day while I was working on a desktop computer, I ran some google searches trying to find a solution, and I found out that if you do shift-numlock and then a 5 on the number pad, that amounts to a middle-click (then you have to do shift-numlock again to resume normal use of the number pad).

(Have you seen the problem with this solution yet?)

I was eager to get home to try this on my laptop, only to feel a crushing humiliation to realize that my laptop does not in fact have a dedicated number pad. (There's a special function key which can convert about a dozen keys on the keyboard into a number pad, but the trick doesn't work on my laptop.)

But then I realized that I could use xmodmap along with the key-handling feature of my window manager. The xmodmap 'pointer' command lets you remap your mouse keys in real time (a left-handed person can use this to make his/her mouse work correctly). If I tell my window manager that control-alt-9 means xmodmap -e 'pointer = 1 3 2' and that control-alt-0 means xmodmap -e 'pointer = 1 2 3', then I can highlight some text (to copy), do control-alt-9, and do a hard-to-screw-up right-click to paste (and then control-alt-0 to resume normal right-click operation).

To do this in fluxbox, just add these two lines to ~/.fluxbox/keys:

Control Mod1 9 :ExecCommand xmodmap -e 'pointer = 1 3 2'
Control Mod1 0 :ExecCommand xmodmap -e 'pointer = 1 2 3'

Xnest

This is basically a distillation of a recent Linux Magazine article ("Using Xnest" by Roderick W. Smith, p. 46 of the March 2007 issue, available at http://www.linux-mag.com/id/3431/ with free registration).

Let's say you're running gnome in Linux. You've installed some other window manager (like XFCE or fluxbox), and you want to try it but don't want to close all your applications and log out (to log in to the other window manager). You can run the other window manager in Xnest. Xnest is like running another X11 instance inside an application window. Try running the following (for fluxbox):

Xnest -ac :1 &
DISPLAY=:1 fluxbox &

This should run fluxbox in a new window. You get all the features of a window manager (wallpaper, multiple desktops, etc.) inside an application window.

I've yet to come up with a particularly compelling use for this. It's mostly (to me) just a stupid human trick. But it may intrigue some of your more easily-impressed friends.

Wireless transfer of electricity

The Energy Blog has an interesting post about transferring power without cables. This technology (being developed by MIT researchers) works sort of like magnetic induction, in which two physically-separated coils transfer power using magnetic fields. But the technique described in the Energy Blog post uses resonant coupling, which works over greater distances with little or no interaction with the surroundings (furniture, people, etc.). So someday this might allow us to run our laptops and cell phones without power cables or batteries.

rtl8180 chipset

If you happen to have a wireless card based on the RealTek rtl8180 chipset and want to use it in Linux without using ndiswrapper (there are probably about 4 people on Earth like this), you may find this interesting/useful.

I have a Linksys WPC11v4 PCMCIA wireless card. There's an open-source driver for it at http://sourceforge.net/projects/rtl8180-sa2400, and the driver lets you run it in monitor mode. Monitor mode is what lets you run wireless network detectors like kismet. (ndiswrapper, which lets you run wireless cards in Linux using Windows drivers, doesn't support monitor mode, even for cards which which do). The released versions doesn't work for me (in CentOS 5), but the CVS version does. You can get the CVS code by running the following:

cvs -d:pserver:anonymous@rtl8180-sa2400.cvs.sourceforge.net:/cvsroot/rtl8180-sa2400 login
cvs -z3 -d:pserver:anonymous@rtl8180-sa2400.cvs.sourceforge.net:/cvsroot/rtl8180-sa2400 co -P rtl8180-sa2400-dev

Then you'll need to edit a couple of files. In
rtl8180-sa2400-dev/r8180_core.c, comment out the lines beginning with MODULE_PARM and MODULE_PARM_DESC (there are four of each, found on lines 137-147 of the file). And in rtl8180-sa2400-dev/Makefile, remove the text MODVERDIR=$(PWD) from line 62. (I have a patch file with both of those edits--leave a comment if you'd like me to send a copy).

Then just run 'make', and then you can run the following commands to insert the kernel modules (the order is important):

/sbin/insmod ieee80211_crypt-r8180.ko
/sbin/insmod ieee80211_crypt_wep-r8180.ko
/sbin/insmod ieee80211-r8180.ko
/sbin/insmod r8180.ko

CentOS 5 follow-up

I've had a week to play more with CentOS 5 on my laptop, and I've overcome a few of the shortcomings that were bothering me last time. It eventually occurred to me that I could use gnome-panel and its pager. That worked out pretty well, but actually I find that I like fbpanel even better. fbpanel is a lot like gnome-panel, but is a little more configurable. And the pager shows scaled-down versions of my wallpaper--not a big deal, but cool.

I was able to build grisbi from source, but I couldn't get OFX support to work. The libofx/openjade/opensp dependency hell was too annoying, so I just turned off that feature. OFX is a file format for financial records. Some financial institutions might be able to deliver your financial records in OFX format, and then you could import them into grisbi (if OFX support is built in). So my build might not be very useful for some people. It's not a feature that I've ever used, so I don't really miss it. I'm just glad to have grisbi working in CentOS 5. Leave a comment if you'd like the spec file.

CentOS 5

I finally got around to trying out CentOS 5 yesterday (if you're not familiar with CentOS, it's a Linux distribution which is generally binary-compatible with Red Hat Enterprise Linux [RHEL]). Here are a few of my first impressions.

I installed CentOS 5 on my laptop. The laptop is about two years old, and it was nothing really special to begin with (1.67 GHz Athlon Mobile, 1 GB of RAM, video hardware which is probably way too lame for beryl/compiz).

The installation is different, in that you can no longer select 'full installation' or 'minimal installation' in the package selection screen. I really liked those features, and I'm sorry to see them go. Packages are now arranged in groups and subgroups, and you can select which groups/subgroups will be installed (but you can't select individual packages--at least, I didn't see how to). One of the subgroups probably more-or-less corresponds to the minimal install ('base system' or something, I think), and I suppose you can select all the subgroups for a full install. But it was nice having those as selection items in CentOS 4.

One of the big new features of RHEL/CentOS 5 is virtualization (they are using xen). I thought I'd try it out, so I selected the virtualization group in the installation process. This installs a xen-enabled kernel, and it's the default kernel (in fact, it didn't install any non-xen kernels). My laptop is rather noisy anyway, but the CPU fan typically ran two levels higher (faster, louder) than usual with the xen kernel, even when the laptop was idle. That was too noisy, so I installed a non-xen kernel package, and the CPU fan is now running at its normal less-noisy rate. So make sure that your computer has good cooling if you try xen.

There are lots of packages missing. This isn't an issue with a non-full installation: the packages just don't seem to be available at all. Not even in the CentOS extras or in DAG's RPMs. Here are a few examples:

1. no xpdf and no gpdf (well, DAG has gpdf, but there's no EL5 build), just evince
2. no xscreensaver (!): there's xlock, which isn't as cool, and DAG has an SRPM for xautolock (I had to remove the BuildRequires from the specfile), but I miss xscreensaver
3. there's no EL5 build for audacity
4. no grisbi (ouch)
   

And I had some trouble building some stuff I like. I use fluxbox, but I can't seem to build fluxter or fbpager, so I'm stuck with no decent pager program.

wpa_supplicant was installed as part of my package selection, but I couldn't make it work. I had to compile a newer version from source.

On the brigher side, it's got more current (than CentOS 4) versions of several packages: OpenOffice 2.0, PHP 5.1, MySQL 5.0, Apache 2.2 (which has mod_proxy_balancer: there was an interesting HowToForge article about mod_proxy_balancer recently).

But all in all, I'm disappointed in losing some of my favorite packages. Guess I need to quit whining and try to contribute specfiles.