Surgeons Net Blog

Photographing the moon

noreply@blogger.com (Neville Dastur) — Sat, 03 Mar 2012 20:50:00 +0000

It was such a clear night tonight I thought I would try and get some nice shots of the moon.

Turned out to be more difficult than I thought. The first lot just came out as bright white circles. After a little reading it seems that bright sunny day settings are best.

So started at ISO 100 F11 1/125, which were okay. But I think the best shot I got was this one at F16 1/80

Note that this was on a fairly cheap Tamron 70-300mm zoom lens. So nothing fancy.

Enjoy ...

noreply@blogger.com (Neville Dastur) — Sat, 04 Feb 2012 17:03:00 +0000

I saw this on a ward the other day. With the current state of funding in the NHS, maybe we will be seeing more of these!

Stop persistent networking interface assignment in cloned virtualbox

noreply@blogger.com (Neville Dastur) — Sat, 04 Feb 2012 16:46:00 +0000

When a Ubuntu virtualbox is cloned the new box network interfaces will not come up as Ubuntu has added some MAC matching rules. To fix this on the machine that will be cloned, do this:

Add:

# ignore VirtualBox virtual interfaces
ENV{MATCHADDR}=="08:00:27:*", GOTO="persistent_net_generator_end"

to /lib/udev/rules.d/75-persistent-net-generator.rules

and delete the file
/etc/udev/rules.d/70-persistent-net.rules

Tilda in Virtualbox Linux guest for OSX host

noreply@blogger.com (Neville Dastur) — Wed, 14 Sep 2011 10:45:00 +0000

As much as I love my Mac, there are some really annoying things. One of which is the keyboard. Why Apple think a delete key is unnecessary only they know!

Anyway, I run a Linux guest using VirtualBox on my Mac and regardless of which keyboard layout you choose the tilda key is not accessible. The solution is to create a .xmodmaprc file in your home directory

In that file add:
!map tilda and grave
keycode 94 = grave asciitilda

Use the file by typing
xmodmap ~/.xmodmaprc

To make it stick you need to logout, login. A dialog will pop up asking if you want to load the xmodmaprc file. Move the file across and click okay

Migrating a windows VM ware box to VirtualBox

noreply@blogger.com (Neville Dastur) — Wed, 17 Aug 2011 11:57:00 +0000

Maybe I'm just blind but I couldn't find VM player for mac. Only a 30 day trial for VM fusion. Any way I got given a VMWare machine image that I needed to use and VirtualBox is my preferred desktop virtualisation solution.

Migrating a Windows machine is a PITA because of the way windows does it's thing but VMWARE don't help either, because it is nearly impossible to remove VMware tools.

Probably the best guide I found to migrating a windows box is http://www.kleinfelter.com/node/135. It also tackles how to get rid of VMWare tools. But unfortunately the you can't seem to get rid of the network drivers. So the article suggests switching to one of the Intel drivers. But of course you don't have network connectivity from the VM to download. So my little addition to this article is how to create your own ISO image with the drivers to load up into the VirtualBox VM.

Download the Intel network drivers from the Intel site
Goto Applications -> Utilities -> Disk Utility
Click New Image
Select Partitions CD/DVD
and 100MB is more than enough space
Select a name for your CD "file"
This file will be mounted and can be found in Finder.
Copy the network driver download to it and eject

The problem now is making an ISO. I found that the convert function in Disk Utility didn't work. So you need to goto the terminal and type this:

hdiutil makehybrid -iso -joliet -o [filename].iso [filename].cdr

Voila you have an ISO you can attach to your virtualbox machine and install the Intel network drivers

Reconnect Mac OSX bluetooth mouse with just the keyboard

noreply@blogger.com (Neville Dastur) — Mon, 09 May 2011 09:37:00 +0000

You might ask why you want to do this. Well it seems to be a common problem that the mac magic mouse keeps disconnecting at crucial moments and what ever you do it doesn't automatically re-connect. I wish apple would make the process of mouse disconnects "magical".

Anyway, if this does happen to you and you don't fancy a reboot follow these steps.

Type Command and space to bring up spotlight
Type mouse
In the list a item under the heading "System Preferences" called mouse should appear
Use the down key to get to it and hit Enter
The searching for mouse dialog should appear.
At this point turn the bluetooth mouse off and on. I think this puts the mouse in discovery mode
When found just hit Enter again

Volia - you should have a connected mouse

Screencast capture on OSX using VLC

noreply@blogger.com (Neville Dastur) — Sun, 06 Feb 2011 12:56:00 +0000

A nice post on howto use VLC to cpature the screen on OSX. I assume this will work on linux too.

Just in case it disapears, the import bit is:

Open VLC as you would do normally
Window -> Errors and Warnings (this will warn you if encoding failed)
File -> Open Capture Device -> Screen
Try to limit the area You are recording by specifying Subscreen parameters – I didn’t have any luck with recording full screen
Tick: “Streaming/Saving”
Click on “Settings…”
Select “File”, click on Browse, select dir where you want to save the file and give it some name
Encapsulation Method: MPEG 4
Transcoding options: tick “Video” and select mp4, Bitrate 512
Untick “Audio” (just to test if it works without it)
Click “OK”
we are back to previous screen, click “Open”

Detecting Application Idle in Qt 4

noreply@blogger.com (Neville Dastur) — Sun, 23 Jan 2011 21:55:00 +0000

The Patient Management System we are writing required a timeout for logins after a certain period had elapsed. So we needed to detect application idle. A couple of examples exist on the the web, but seemed incomplete and not thread safe. I also wanted a singleton class model so that I could have notifications of idle in any of my QObjects. So here is my implementation. Comments and improvements will be appreciated.

Header File:

#ifndef IDLETIMER_H
#define IDLETIMER_H

#include <qobject>
#include <qmutex>
#include <qevent>
#include <qtimer>

class IdleTimer : public QObject
{
Q_OBJECT
public:
// Singleton class stuff
static IdleTimer* instance(QObject *parent=0, int seconds=0) {
static QMutex mutex;
if (!m_Instance) {
mutex.lock();
m_Instance = new IdleTimer(parent, seconds);
mutex.unlock();
}
return m_Instance;
}

static void drop() {
qDebug("IdleTimer dropped ...");
static QMutex mutex;
mutex.lock();

m_timer->stop();
if(m_timer) delete m_timer;

if (m_Instance)
delete m_Instance;
m_Instance = 0;
mutex.unlock();
}

void start(int seconds = 0);
void stop();

private:
explicit IdleTimer(QObject *parent, int seconds);
explicit IdleTimer() {}
~IdleTimer() {}

IdleTimer(const IdleTimer &); // hide copy constructor
IdleTimer& operator=(const IdleTimer &); // hide assign op

static IdleTimer *m_Instance;
static QTimer *m_timer;

static QMutex m_timeoutMutex;
static int m_timeout;

signals:
void idle();

private slots:
void idleTimeout();

protected:
bool eventFilter(QObject *obj, QEvent *ev);
};

#endif // IDLETIMER_H

And the implementation

/*!
* Small class for detecting idle in the applcation
*/

#include "IdleTimer.h"

// Static initialisers
IdleTimer *IdleTimer::m_Instance = 0;
QTimer *IdleTimer::m_timer = new QTimer();
int IdleTimer::m_timeout = 0;
QMutex IdleTimer::m_timeoutMutex;

/*!
* Class constructor
*/
IdleTimer::IdleTimer(QObject *parent, int seconds) :
QObject(parent)
{
m_timeoutMutex.lock();

if (seconds)
m_timeout = seconds;

Q_ASSERT(parent);
Q_ASSERT_X(m_timeout, "IdleTimer Constructor", "The timeout must be specified in the first call to instance.");

parent->installEventFilter(this);
m_timer->singleShot(m_timeout*1000, this, SLOT(idleTimeout()));

m_timeoutMutex.unlock();
}

/*!
* Either reset the timeout to a different value to restart the timer
*/
void IdleTimer::start(int seconds/*=0*/) {
m_timeoutMutex.lock();

if(seconds)
m_timeout = seconds;

Q_ASSERT_X(m_timeout, "IdleTimer reset", "A timeout must be specified either in this call or in the first call to instance.");

m_timer->start(m_timeout*1000);

m_timeoutMutex.unlock();
}

void IdleTimer::stop() {
m_timeoutMutex.lock();
m_timer->stop();
m_timeoutMutex.unlock();
}

/*!
* The vent filter
*/
bool IdleTimer::eventFilter(QObject *obj, QEvent *ev)
{
if(ev->type() == QEvent::KeyPress ||
ev->type() == QEvent::MouseMove)
// now reset your timer, for example
IdleTimer::m_timer->start();

// Must return to allow further processing
return QObject::eventFilter(obj, ev);
}

/*slot*/
void IdleTimer::idleTimeout() {
qDebug("Application has been idle, emitting idle signal ...");
emit idle();
}

SpiderOak Backup

noreply@blogger.com (Neville Dastur) — Fri, 24 Dec 2010 22:44:00 +0000

I have been using SpiderOak for my offline back up solution for some time now. The main advantage I have found is that you don't need a separate folder like in Dropbox and the synchronisation feature works really well. So I currently have three computers all sync'ing wonderfully with each other. Anyway, there is now a referral programme and so I thought I would take advantage. If you use this link you get the standard 2GB + another 1GB free for life.

Download SpiderOak Backup and get extra 1GB free

Mounting virtualbox shares in a linux (Ubuntu) guest

noreply@blogger.com (Neville Dastur) — Wed, 21 Apr 2010 22:10:00 +0000

Mounting VirtualBox shares in a Linux guest is not as straight forward as for a Windows guest. I have only tried this on a Ubuntu guest but I see no reason why it wouldn't work in other flavours.

Some pre-requisites:

Make sure the VirtualBox guest additions have been installed. There are plenty of guides about this
When you create your shared directories DO NOT accept the default name. Use a prefix. For example HostDocuments for the host Documents folders instead of Documents.
The reason for this is if you use the default name a protocol error will be reported when you mount the shared dir. I don't know why but this small work around fixes the issue
Make sure the vboxvfs module is loaded by adding vboxvfs to the end of /etc/modules

sudo sh -c 'echo "vboxvfs" | cat >>/etc/modules'

Now we need to allow mounting of vbox shares by normal users.

sudo select-editor and make sure nano is selected. This is a much nicer editor than vi
Now edit the sudoer file using sudo visudo.

Add the line: %plugdev ALL=(ALL)NOPASSWD:/sbin/mount.vboxsf
It may be that the group plugdev is a Ubuntu only group. Choose a group that all users belong to. Or create a 'users' group and add the users to it
Create a mounting script in /usr/local/bin.

sudo nano /usr/local/bin/mountVboxShares

Paste the following code, but replace the variables at the top and add sections as appropriate.

#!/bin/bash PROJECTDIR="$HOME"/Projects PROJECTSHARE="HostProjects" DOCSDIR="$HOME"/Documents DOCSSHARE="HostDocuments" if [ ! -d "$PROJECTDIR" ]; then mkdir "$PROJECTDIR" fi /usr/bin/sudo mount.vboxsf -o uid=`id -r -u`,gid=`id -r -u` "$PROJECTSHARE" "$PROJECTDIR" if [ ! -d "$DOCSDIR" ]; then mkdir "$DOCSDIR" fi /usr/bin/sudo mount.vboxsf -o uid=`id -r -u`,gid=`id -r -u` "$DOCSSHARE" "$DOCSDIR"
Allow everyone to execute this script sudo chmod 755 /usr/local/bin/mountVboxShares
Finally add the mount script to the end of the system wide profile script sudo sh -c 'echo "/usr/local/bin/mountVboxShares" | cat >>/etc/profile'

Converting Joomla sites from 1.0 to 1.5 cheatsheet

noreply@blogger.com (Neville Dastur) — Mon, 01 Mar 2010 19:10:00 +0000

Some useful links for Joomla 1.5 component development:

The guys at the Art of Joomla have a really nice crib sheet for converting your 1.0 extensions to 1.5. Well done and thank you.
Using the JHTML:: functions to create lists

Ubutnu ext3 to ext4 upgrade - won't mount filesystem!

noreply@blogger.com (Neville Dastur) — Mon, 08 Feb 2010 15:02:00 +0000

I have just had a little heart stop moment.

I followed the Ubuntu wiki instructions on migrating from ext3 to ext4. After the tune2fs bit I rebooted as instructed and the system could not mount the new filesystem. Errors about bad superblocks and bad group descriptors, but nothing being done about them. fsck did not run correctly and I was left with an un-mountable drive, so I could even mount as ext3. Ahhhh....

Fortunately I have a live CD install of 9.10 on USB from which I could boot and run a fsck.ext4 on my partition.

So my suggestion is that before migrating from ext3 to ext4 do two things:

BACKUP all your data
Do the migration from a live CD / USB. The advantage of this is that you save on all the reboots too.

Setting up qt4 with visual studio 2005 and 2008

noreply@blogger.com (Neville Dastur) — Wed, 07 Oct 2009 19:30:00 +0000

It is not clear (or wasn't to me) how to use QT4 with Visual Studio. The key to the problem is that you need to re-compile QT4 for Visual Studio. If you are not using MingGW at all then you can do all this in the original QT directory. Otherwise copy the entire c:\qt\2009.03 directory to something like c:\qt\2009.03_vs2008

Open a VS command line prompt so that all the env vars are set up.

Run the configure script, my suggestion is:
C:\Qt\2009.03\qt>configure -no-qt3support -no-opengl -platform win32-msvc2005 -no-libtiff -no-dbus -no-phonon -no-phonon-backend -opensource -debug-and-release

Let it do it's thing

Then type nmake to build the VS libraries

Notes:
Use nmake confclean to clean the directory before running a new configure cmd

Setting up PostgresSQL on Ubuntu

noreply@blogger.com (Neville Dastur) — Tue, 29 Sep 2009 22:57:00 +0000

Most of my database use has been with MySQL to date as I have LAMP installations for websites but I was looking for a DB to use with a new desktop application of ours. It seems that Postgres may be a better option. Below are the steps I needed to get a Postgres server running on my laptop.

1) Install the packages
# sudo apt-get install postgresql postgresql-client pgadmin3

This will install the latest versions, which for ubuntu 9.04 at this time is 8.3 if an older version installs then change the references to directories below as appropriate.

2) Change the admin passwords

# sudo -u postgres psql template1
This will start up the command line admin tool and select the template1 db which seems to be where postgre stores user credentials

# ALTER USER postgres WITH PASSWORD 'new password';
and quit by typing \q

3) Change the ubuntu postgres user password. This is a conveinence step as all the conf files are created with postgres user and group. You could add or edit them as root with sudo and then make sure they are all chown to postgres:postgres

# sudo passwd -d postgres
Will delete the current postgres password (needed otherwise you are asked for it in the next step)
# sudo su postgres -c passwd
Enter a new password. For simplicity use the same password as the admin user above, but can be anything so long as you remember it

Restart the server with
# sudo /etc/init.d/postgresql-8.3 restart

You can now use the pgAdmin tool to connect to the DB

Additions to the Surgical Tutorials

noreply@blogger.com (Neville Dastur) — Wed, 02 Sep 2009 18:53:00 +0000

I have been making some additions to the Surgical Tutorials section of the website. Four topics added are:

The Airway and Ventilatory Management is part of a new ATLS notes section and hopefully the other tutorials will also provide for useful revision notes.

EWTD 48 hour opt out survey

noreply@blogger.com (Neville Dastur) — Sun, 16 Aug 2009 11:56:00 +0000

We have been running a short EWTD survey on the Surgeons Net site about the 48 hour EWTD week and opting out. If you haven't completed the survey then please contribute. But do note that ASiT and BOTA are going to be conducting a more detailed, longer survey in September.

If you are interested in the results then they are available live on line too.

Target Google AdSense even more by rating your content

noreply@blogger.com (Neville Dastur) — Sun, 25 Jan 2009 12:22:00 +0000

There is a nice article on AdSense published recently on DevShed. For my own note I had no idea you could direct what content you wanted Google to concentrate on for displaying relevant ads.

Put the main content inside these comment tags:

And things you want ignored inside:

Firefox 3 sesson restore

noreply@blogger.com (Neville Dastur) — Mon, 17 Nov 2008 22:59:00 +0000

Not sure why but firefox seemed to lose it's session restore feature for me. Maybe something to do with having tab mix plus installed prior to the 2 -> 3 upgrade.

Anyhow here is how to restore session saving.

Enter about:config in the address bar and say yes to the behave yourself warning!

Search down for "browser.sessionstore.resume_session_once" and change the setting to true.

and restart ...

That's it.

Clamav with Qmail-Scanner

noreply@blogger.com (Neville Dastur) — Wed, 04 Jun 2008 12:49:00 +0000

Probably the best article on getting clamav to work with Qmail Scanner

http://qmail.jms1.net/clamav/qmail-scanner.shtml

WEBSITES DOWN DUE TO FIRE AT SERVER HOST

noreply@blogger.com (Neville Dastur) — Mon, 02 Jun 2008 07:54:00 +0000

Unfortunately there has been an fire at the main data center where our servers are hosted and hence the websites and email are down.

The server company are expecting to starting bringing servers back online this evening, but it may be tomorrow morning before the network is fully restored.

Thank you for your patience.

Just a reminder of a great x-platform SVN client

noreply@blogger.com (Neville Dastur) — Sat, 26 Apr 2008 19:21:00 +0000

http://rapidsvn.tigris.org/

Setting up a subversion server Redhat CentOS

noreply@blogger.com (Neville Dastur) — Thu, 21 Feb 2008 23:48:00 +0000

First some useful reference links:

http://www.tgharold.com/techblog/labels/SubVersion.shtml
http://www.daniel-skinner.co.uk/setup-subversion-and-trac-on-centos-5/06/01/2008
http://www.subversionary.org/howto/setting-up-a-server-on-fedora-core-4

A Script to do the plesk directory permisson setup

noreply@blogger.com (Neville Dastur) — Sun, 17 Feb 2008 20:03:00 +0000

I have previously posted about changes to the plesk httpdocs directory to get it to work well with Joomla. This is a little bash script I knocked up to do the job. Just pass the username as param 1


#!/bin/bash

# First check that this is a valid username
grep "^${1}:" /etc/passwd > /dev/null 2>&1
if [ "$?" -ne "0" ]; then
  echo "Sorry, cannot find user ${1} in /etc/passwd or you didn't supply a username"
  echo "Usage: ${0} "

  exit 1
fi

userdir=`grep "^${1}:" /etc/passwd | cut -d: -f6`

if [ -d ${userdir} ] ; then
 echo "Changing to directory ${userdir}"
 cd ${userdir} && chown -R ${1}:psacln httpdocs && chmod -R g+w httpdocs && find httpdocs -type d -exec chmod g+s {} \; && /etc/init.d/httpd reload
fi

Monitoring all apache virtual hosts on plesk with logwatch

noreply@blogger.com (Neville Dastur) — Sat, 16 Feb 2008 16:00:00 +0000

The standard Plesk install has logwatch setup to just monitor the default httpd log, i.e /var/www/httpd/*

This is miss most things as the log file output of all the virtual hosts are not parsed. So I made a little bash script to create a load of new logwatch conf files to parse all my virtual host logfiles too. You will need to run this script each time a new domain is created. A know there is a Plesk way to run custom scripts on events, but I'll leave that for another day.


#!/bin/bash

##
## Script to create conf files and script links on a Plesk
## server that monitor all the apache log files 
##
## Visit blog.surgeons.org.uk for updates

## Location of the virtual hosts directories
vhost_root=/var/www/vhosts/

## Various logwatch directories
dir_services="/etc/logwatch/conf/services"
dir_logfiles="/etc/logwatch/conf/logfiles"
dir_scripts="/etc/logwatch/scripts/services"
http_script="/usr/share/logwatch/scripts/services/http"

## Now iter over each directory
for domain in $( ls -Ichroot -Idefault $vhost_root ); do
if [ -d "${vhost_root}${domain}" ]
then
 echo "Making services logwatch enteries for ${domain}"
 domain_us=`echo $domain | tr . _`
 (
 cat <<-END_OF_SERVICES_CONF        

###########################################################################
# Configuration file for $domain http filter         
# See blog.surgeons.org.uk for updates         ###########################################################################
Title = "httpd - $domain"

# Which logfile group...
LogFile = http_$domain_us
END_OF_SERVICES_CONF ) > ${dir_services}/http_${domain_us}.conf


 echo "Making logfiles logwatch entries for ${domain}"
 (
 cat <<-END_OF_LOGFILES_CONF
########################################################
#   Define log file group for http_$domain_us
#   See blog.surgeons.org.uk for updates
#######################################################
LogFile = /var/www/vhosts/$domain/statistics/logs/access_log
LogFile = /var/www/vhosts/$domain/statistics/logs/access_log.processed
LogFile = /var/www/vhosts/$domain/statistics/logs/access_ssl_log
LogFile = /var/www/vhosts/$domain/statistics/logs/access_ssl_log.processed

# If the archives are searched, here is one or more line
# (optionally containing wildcards) that tell where they are...
# If you use a "-" in naming add that as well -mgt

Archive = /var/www/vhosts/$domain/statistics/logs/access_log.processed.?.gz
Archive = /var/www/vhosts/$domain/statistics/logs/access_ssl__log.processed.?.gz         

# Expand the repeats (actually just removes them now)
*ExpandRepeats

# Keep only the lines in the proper date range...
*ApplyhttpDate
END_OF_LOGFILES_CONF ) > ${dir_logfiles}/http_${domain_us}.conf


## Make the script links
echo "Creating script link for ${domain}"
ln -s ${http_script} ${dir_scripts}/http_${domain_us}

fi

done

Suhosin PHP hardening

noreply@blogger.com (Neville Dastur) — Fri, 15 Feb 2008 15:57:00 +0000

A PHP hardening (security patch) worth checking out

http://www.hardened-php.net/suhosin/index.html