keycode 11 = 2 at twosuperior oneeighth twosuperior oneeighth
keycode 94 = 0x60 0x7e
keycode 48 = apostrophe quotedbl dead_circumflex dead_caron dead_circumflex dead_caron
keycode 49 = numbersign plusminus

You can place these in your home directory, e.g. $HOME/.xmodmap, or you could place them in something like /etc/X11/Xmodmap and add the following line to /etc/X11/xinitrc/Xsession

[ -f /etc/X11/Xmodmap ] && xmodmap /etc/X11/Xmodmap

The key mappings have been tested on Centos 5.7 and 6.1, although making it global, as in the line above, on seems to work on Centos 5.7.

"name2labels" is not exported by the Net::DNS module
Can't continue after import errors at /usr/lib/perl5/vendor_perl/5.8.8/Net/DNS/RR/NSEC3.pm line 24
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/Net/DNS/RR/NSEC3.pm line 24.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/RR.pm line 172.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/RR.pm line 185.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Packet.pm line 16.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Packet.pm line 16.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver/Base.pm line 26.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver/Base.pm line 26.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver/UNIX.pm line 9.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver/UNIX.pm line 9.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver.pm line 19.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS/Resolver.pm line 22.
Compilation failed in require at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS.pm line 67.
BEGIN failed--compilation aborted at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/Net/DNS.pm line 67.
Compilation failed in require at /usr/bin/sa-update line 80.
BEGIN failed--compilation aborted at /usr/bin/sa-update line 80.

Searching Google seems to suggest that this is caused by a security update by RedHat to the perl-Net-DNS that ships as part of RedHat EL 5.7, which CentOS 5.7 is derived from.  I did try updating the Perl Net::DNS module via cpan but this did not fix the issue.

Though I’m not a big Perl programmer I decided to have a look at the sa-update script to see if I could fix it myself.  So what I decided to do was replace line 24 in NSEC3.pm.

Old line:

use Net::DNS qw( name2labels );

New line:

use Net::DNS;

So now sa-update -v displays:

Update available for channel updates.spamassassin.org
Update was available, and was downloaded and installed successfully

I know this is probably not the best fix to apply for the given problem, but it does fix my problem for now.  Hopefully others will find this useful.

For example: I use the Kensington Expert Mouse (which is actually a trackerball), which has four buttons; so I can program one as a drag-lock and one as a double-click.  This device is fully support under OS X as well as another known proprietary, unstable, operating system.  On occasions I have emailed Kensington to ask about bring support to Linux; and each time they just respond saying that there isn’t enough demand for it; they won’t even release a spec to help the Opensource community write the appropriate software/driver.

I have experimented with the accessibility options under a few Linux distributions and have had some limited success in making the Kensington Expert Mouse functional.  Setting one of the buttons as a double-click is fairly simple but trying to set one button to toggle drag-lock on and off, as I do with OS X, I have not yet mastered.

Getting back to the title of this post; I was pleased to here that the Accessible Computing Foundation has been set up to try and make Computers, particularly running Linux / Opensource Software, more accessible to people with disabilities.  I recommend and anyone reading this post go and check out their site for more details.  But the basic idea is that the ACF will take donations so they can pay programmers to develop software/drivers to make using computers more accessible; and the software will be given to the Opensource community, most likely licensed under something like GPL.

If you would like to see the Kensington Expert Mouse working under Linux then I urge you to email Kensington with your request and also let me know either through email or twitter. I also urge you to give support to ACF, either by donation, some time, or some coding if you can.

I want to see Linux become fully accessible to everyone, so nobody has to depend on proprietary software for everyday computing needs.

For anyone interested the my .Xmodmap (under the Linux guest) contains:

keycode 94 = 0x60 0x7e
keycode 49 = numbersign plusminus

Note: This is for the Apple Wireless (UK) 2011 keyboard an maps the tilda and reverse tick to the key left of Z and the hash and plus/minus to the key below esc.