trivial shennanigans

Missing XInputExtension when using XForwarding over SSH

I recently had some issues whilst trying to tunnel an Xsession over to another machine (basically as I was too lazy to walk downstairs to my Mythtv box to use xxdiff to analyse 2 config files).

Using this command
ssh -X mythtv

resulted in many error messages once i ran any app that would have launched a Xdisplay:

mythtv ~ # xxdiff httpd.conf httpd.conf.old
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
Major opcode: 55
Minor opcode: 0
Resource id: 0x1a6
X Error: BadWindow (invalid Window parameter) 3
Major opcode: 2
Minor opcode: 0
Resource id: 0x1a6
Xlib: extension "XInputExtension" missing on display "localhost:10.0".
Failed to get list of devices
X Error: BadWindow (invalid Window parameter) 3
Major opcode: 2
Minor opcode: 0
Resource id: 0x1a6
X Error: BadWindow (invalid Window parameter) 3
Major opcode: 2
Minor opcode: 0
Resource id: 0x1a6
X Error of failed request: BadGC (invalid GC parameter)
Major opcode of failed request: 60 (X_FreeGC)
Resource id in failed request: 0x3200000
Serial number of failed request: 131
Current serial number in output stream: 133

Apparently the current version of SSH limits the X Window extensions that can be used. XInputExtension is one of these. If instead you use “-Y” it will accept ALL these X Window extensions and it works

ssh -Y mythtv


Laziness promotes education.

Screencasts of Installing MythTV Via MythDora 4.0

Slashdot | Screencasts of Installing MythTV Via MythDora 4.0

Seen on /. a new @boot and install from a single CD” MythTV distro. This time based on a more mainstream RedHat/FC one.

I’ve been using a MythTV box as my ONLY TV for about a year now. With 2 Freeview (UK DVB-T) tuners and a single tuner connected to a dish with multiple LNB’s pointing at Hotbird and Astra. I can wholeheartedly recommend it. A fine piece of software


Apple security updates breaks Samba/NFS?

Apple security updates

This may be a real coincidence but since I updated my Macbook pro with this update from Apple I cannot connect to my Linux box’s SAMBA nor NFS shares? Hmmm. Further invesitigation needed.

Computergeekery Mac



Incidentally thanks to a cool new utility I discovered about 10 mins ago, I am now typing this on my Macbook with the keyboard attached to my Linux box. How cool is that?

Basically I’ve been looking for a decent DVI/USB LVm, but appalled at just how expensive they are. So I’ve been looking for a software solution. This is effortless to setup, and seems very robust.

The utility has a client server type connection. Running on OSX, Linux and/or Windows. You run the server on the machine with the physically connected mouse and keyboard, and a client on each machine that you want to share the mouse/keyboard to. It also shares the clipboard too. The URL above was copied from Firefox running on the Linux box, and pasted into the Macbook.Took me 5 mins to setup

The only downside I can see so far is that the Apple CMD and OPTION keys don’t work on the Mac. I guess since the linux box cannot recognise these to pass the key strokes across.
Am impressed. Of course now I need to buy myself a second 24″ widescreen monitor.

RAID10 over 6 devices

I’ve been struggling to find the best layout for my 6 drive RAID10 device: I settled for near with 2 copies, and a 1M chunksize. As far as I understand this I get the r/w speed equivalent to RAID0 with this. It means that each block has two copies, which are striped across 2 drives. So you get the RAID0 speed, with the redundancy of RAID1. Plus since this is kernel RAID10, it’s a lot easier to create and more flexible than a mirror of raid0 devices.
mdadm --create /dev/md1 --chunk=1024 --level=raid10 --layout=f2 --raid-devices=6 /dev/sd[defghi]1

So far the speed seems to be OK. Nothing at all spectacular though. At the moment I think my limitation is that I am running a 64bit PCI-X u320 card in a 32bit PCI slot since my motherboard only has these…. I need to get myself a PCI-X dual socket 604 motherboard. Trouble is these are quite expensive…..! In my quest to silence the machine I replaced the fan in my Graphics card with a quieter one. Unfortunately whilst doing so I knocked of a small component. The card works fine except that I get visual aretefacts on any hw accelerated graphics now. I’ve alwasy steered away from upgrading my motherboard due to the fact I would need to also buy a new GPU to go with PCI-E slots. But if this is now damaged perhaps I should splurge out. Hmmm.

Computergeekery Tips trivial shennanigans

HOWTO Find broken symbolic links – Gentoo Linux Wiki

HOWTO Find broken links – Gentoo Linux Wiki

I was trying to find some broken links. however, although using
find . -type l

shows all links, it does nto use the cool flashing RED that BASH can do to shwo a broken links. So doing a quick Google turned me to this Gentoo howto: Nice n easy!
find . -type l | (while read FN ; do test -e "$FN" || ls -ld "$FN"; done)

Mac trivial shennanigans

HASH key on a Mac Keyboard with Linux

Right I’ve had a bit of a palaver with the HASH key on my Mac. Well actually with a Mac keyboard attached to a Linux box. After getting my nice new MacBook Pro, I had a issue trying to find the hash key. (How long until my nice new MacBook Pro loses the nice new?). Anyway to cut a long story short it’s ALT + 3. Not too much hassle, and apparently a common thing with Mac UK keyboards.

When i finally settled down to working, I’ve started plugging in the MacBook to my Del 24″ widescreen monitor, and sharing the keyboard and mouse via a cheap USB switch. So with two clicks I can switch between the mac and My Linux box, without the vast expense of a DVI/USB KVM (do they even exist?). The Dell has a VGA and DVI input. so that’s very convenient. To make it easier I’ve plugged in a Apple keyboard to the switch. Linux behaves quite well with this. However, for the life of me I’ve not been able to fathom out how to type HASH in linux with the Apple keybaord attached. Untuil now….

It’s CTRL + SHIFT + 3

How odd!

Linux-raid Wiki

Main Page – Linux-raid

For all you RAIDHeads out there, here’s the RAID Wiki. The old LDP RAID howto was getting a bit long in the tooth, and needed a lot of refreshing to reflect the increased use of the far better MDADM than RAID-tools.

More needs to be added, but it’s getting there!


Configuring Boot Behavior for Alpha Systems

Configuring Boot Behavior for Alpha Systems

Whilst playing with my Alpha 600a workstation (Cheers Andres!), I’ve been struggling to find out how to automate booting from the bios (well the alpha version of a bios!).

Show bootdef_dev

will show you the default boot device.

set bootdef_dev

will set it. In my case this is a SCSI device on ID3. so
set bootdef_dev dkc

running ,code>boot now boots from that device. Rather than having to run boot dkc

Now all I just need to do is find out how to make it boot without prompting…!!!

EDIT… Aha!!!  when a default boot device is set, it will be booted automatically!!  Cool!


Repairing MythTV tables

MySQL 5.0 Reference Manual :: How to Repair Tables

I’ve just been trying to backup my MythTV tables. Previously I’ve used PHPMyAdmin. However, I thought I would try command line and automate it.

mysqldump -u root -p mythconverg > mythconverg-`date +%F`.sql
However, I constantly got a error message
Can't open file: (errno: 145) when using LOCK TABLES mythtv

So i discovered I needed to repair the tables. The above docuimentation is pretty easy but basically.

cd /var/lib/mysql.mythconverg
myisamchk -e *.MYI

Then run the following command on each table that shows errors:
myisamchk -r -q program.MYI

Easy peaasy lemon squeezy!