Evince broken: unhandled x-extension-pdf

On Linux and the Gnome Desktop, Evince is the default application for viewing Adobe Acrobat (PDF) files. Recently, it started giving me the message “Unhandled MIME type: ‘application/x-extension-pdf'”. Here’s how I fixed it.

1. Edit $HOME/.local/share/mime/packages/Override.xml
2. Replace “application/x-extension-pdf” with “application/pdf”
3. Run “update-mime-database $HOME/.local/share/mime”

[Reportedly](http://www.mail-archive.com/evince-list@gnome.org/msg00485.html), a bug in the Nautilus file manager causes this behavior.

XRandR in Fedora 8

Fedora 8 ships XRandR 1.2 (the X Rotate and Render Extension), which makes it possible to render a screen onto an overhead projector, among other things. Here’s instructions on [how to do useful things with XRandR](http://www.thinkwiki.org/wiki/Xorg_RandR_1.2#Using_xrandr_to_do_useful_things) (not Fedora specific). For now, control of XRandR is handled through the command line. In Fedora 9 or 10, there will likely be better user interfaces to configure XRandR.

LatencyTOP

Jake Edge writes “Stuttering audio or an unresponsive desktop – typically caused by operating system latency – are two things that annoy users. They can be difficult problems to diagnose, though, as they are transient and buried deep inside the [Linux] kernel. A new tool, [LatencyTOP](http://www.latencytop.org/), seeks to provide more information on where latency is occurring so that it can be fixed or avoided.”

Read more: [http://lwn.net/Articles/266153/](http://lwn.net/Articles/266153/)

Getting core dumps on RHEL/CentOS 4, 5, Fedora

Sometimes, it’s nice to get core files, system wide, on a RedHat, CentOS, or Fedora Linux system. Here’s how: [http://kbase.redhat.com/faq/FAQ_49_3652.shtm](http://kbase.redhat.com/faq/FAQ_49_3652.shtm)

The “[core manpage](http://linux.die.net/man/5/core)” is also useful, in particular, the bit about /proc/sys/kernel/core_pattern.

Freeware Linux filesystem reader for Windows

This Linux filesystem reader reportedly works with Windows Vista (as well as other versions of Windows):
[http://www.diskinternals.com/linux-reader/](http://www.diskinternals.com/linux-reader/)

There’s also a utility to recover deleted files from Linux partitions:
[http://www.diskinternals.com/linux-recovery/](http://www.diskinternals.com/linux-recovery/)

Gnome Slideshow Screensaver Sanity

The default setup for Gnome’s GLslideshow is highly annoying on Fedora 8, and there’s not an easy way for users to individually configure it. Here’s how. As ‘root’, do the following:

Edit `/usr/share/applications/screensavers/xscreensaver-glslideshow.desktop` and replace

Exec=glslideshow -root

with

Exec=glslideshow -root -duration 15 -zoom 100 -pan 1 -titles

Linux & Kodak EasyShare 5100 All-in-one printer

Up to this point, our family has used Epson inkjet printers. We valued the archival-quality ink and I valued the Linux support. Unfortunately, Epson ink is expensive — very expensive.

Kodak entered the inkjet market last year and offered vastly lower ink price, making their printers a compelling choice. When our Epson printer started having printing problems, even with new ink cartridges, we made the plunge and bought a Kodak 5100 all-in-one printer/scanner/copier. So far, we’ve been pleased with the result.

Linux support didn’t seem to be an issue, since we do nearly all of our printing from Windows. Now that we have a laptop, I thought it would be nice to hook the Kodak printer up to my samba print server.

Unfortunately, there are no Linux drivers for the printer, which means it won’t work to have Samba serve up the printer. I contacted Kodak, wondering if they plan on offering Linux drivers. I’ve included their response, which boils down to this: *Kodak designed the printer to use USB protocols that aren’t yet supported by Linux*. Whether it was a good technical decision or not, I don’t know. I can’t tell, from their response, whether Linux will have the appropriate USB drivers in the near future or not.

> Greetings Jared,
>
> Thank you for your recent visit to the Kodak Web site and question about your Kodak EasyShare 5100 All-in-One Printer.
>
> Thank you for visiting the Kodak web site and your inquiry regarding Kodak support for Linux operating system with Kodak products. Currently there is no support for Kodak products on the Linux OS by Kodak. Our Kodak software engineers are well aware of the Linux operating system. We appreciate your concern for this operating system and interest in enabling Kodak products to work with it.
>
> Kodak continues to follow the Linux Operating system. We noted, as far back as March 30, 1999, that Linux announced support of a Linux-USB driver that only worked with UHCI controllers. Since UHCI controllers represent only a portion of the PC market, Linux-USB was very limited and was very preliminary even six months ago.
>
> We had the same situation in the past with preliminary Microsoft-USB drivers and now version 2 USB as well. Sometimes, the availability of these drivers simply does not match our product release dates. Even after the support is there, as is the case with Microsoft version 1, we still have to update our Kodak web site with the latest driver patches to keep in step with Microsoft-USB patches. In addition, Kodak has worked very closely with the USB IF Working Group on the USB standard participating in numerous USB “Plug Fests” where we test out our hardware and software on a variety of computers with various “chip sets”.
>
> In the past, prior to the release of Microsoft Windows 98, Kodak worked intensely with the staff at the Windows Hardware Quality Labs (WHQL) to achieve “Windows Logo”. This was no small feat with the USB technology forming the basis of the DVC323 and later products and the Windows 98 operating system. As a result, the DVC323 passed all USB compliance testing with Windows 98. I am not sure that there is such a rigorous test standard for Linux-USB. If not, this has serious implications on our technical support staff and the cost for providing a Linux-USB
> driver.
>
> We understand the issue with devices based on the CPiA chip set and once again are faced with a problem with Linux-USB support in that isochronous transfer is not yet fully implemented. There is a distinct difference when a company claims “USB support” it does not always mean “full USB support”. Kodak relies on full support for UHCI and OHCI host controllers as well as their corresponding USB transfer types. The support for this simply is not there yet.
>
> As Linux-USB becomes fully implemented and released with the Linux OS, Kodak may investigate the technical feasibility of developing Linux-USB drivers for future products. I am confident that our technical teams would be able to provide support once Kodak analyzed the business case for such support.
>
> Thank you for contacting Kodak. If you have future questions on Kodak products or services, visit our site, as we continually add information to enhance our service.
>
> We are glad to be of service and are here for you if you need us in the future. Please reply to us “with history” if you need to respond to this email.
>
> Best Regards,
>
> Cristian P
>
> Kodak Information and Technical Support
> www.kodak.com/go/support
>

‘fuser’ linux command

I recently learned about the [`fuser`](http://www.google.com/search?q=fuser+linux+man+page) command, which may be useful when I want to unmount a file system that is in use ([`lsof`](http://en.wikipedia.org/wiki/Lsof) is also handy):

fuser -mu /media/USBFLASH # list pids and usernames with files open
fuser -muki /media/USBFLASH # kill, with a prompt, pids with open files

However, a lazy unmount is often sufficient:

umount -l /media/USBFLASH