TechHobby

I have finally got round to installing an up to date version of Linux on my 1.2GHz Athlon PC. To make space for it, I overwrote a 6 Gb partition on my hard disk that contained an older distribution of Mandrake.

Installation went smoothly, taking a couple of hours. It replaced my PC's boot up menu without asking me whether I wanted it to do this. However an option on the new menu allows me to boot into windows as before.

My hardware such as graphic card and printer were detected okay, but there was no built in driver for my wireless network card. I installed the kernel source code and downloaded the 'Ralink' network driver. It compiled okay, and I was able to get the module working, but no wireless connection. After downloading and compiling the QT gui libraries over-night, I compiled the Ralink Utility that came along with the drivers. After running this, I was able to connect to the network.

Everytime I booted I had to run a terminal as the root user, run the Ralink Utility and type in or copy and paste in the 26 hex-digit encryption key. To reduce the hassle, I modified the source code so that I can leave the key field blank and just press okay, and the correct key will automatically be used. Also I wrote a small wrapper program to login as root using 'sudo' and run the utility.


#include <stdlib.h>
main()
{
system("echo password | su -c /home/leehanken/RaConfig2500 &");
}


Now it just takes a couple of clicks when I first boot up to get connected to the network.

It is scary how little time, money and effort is now needed in terms of technical work to set up a powerful 'dynamic' web site. A dynamic web site is one where the information on it changes regularly, and is stored in a database. These include typical applications such as content management, ecommerce and bulletin boards.

To illustrate I have chosen one from each of these three categories and installed them into a test environment on my laptop, where I run the 'apache' web server and 'mysql' database system.

This first one is an open source bulletin board in which people can discuss some topic, ask each other for help, etc. It is called 'phpBB', php being the programming language it was written in, and BB standing for bulletin board.

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The second one is an ecommerce web site called 'oscommerce', which is used to sell products or services online, by providing users with a catalogue and taking their orders and credit card details.

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The final one is a content management system called 'mambo', which allows one or more editors to write articles or information for their audience, which is automatically formatted according to the wishes of a designer who controls the look, feel and structure of the finished web site.

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Installing these web applications assumes some pre-requisites - that your web hosting company supports the 'php' programming language and the 'mysql' database system. Once these have been set up, installation is relatively simple. First I downloaded the respective packages from the open source projects, and unzipped them into my web directory.

An important step at this stage was to change the permissions so that the application can modify itself at installation time.

Then I created the empty databases using a tool called 'phpmyadmin' which is usually provided by the web hosting control panel.

Then I pointed my web browser at the appropriate installation page for the web site I was setting up, and entered the name of the database, the database user name and password, and any other details requested.

The final step was to delete the installation directory, so my users would not be able to tamper with the way the database was set up.

And voila, the three dynamic web sites, along with their test data were set up and ready to be customised, and used.

Java is like an international language. Almost every modern computer or mobile phone even can understand it, but at a slower speed than when they process their native tongue.

To write programs in Java the software development kit has to be downloaded from Sun Microsystems.

I found that the bundled development tool NetBeans ran painfully slowly on my laptop, so had a look around for something a bit simpler, and found some nifty free software called JCreator Lite Edition.

A new Java program starts of life as a grey rectangle and the only option is exit. To this I added another option...

JMenuItem menuFileOpen = new JMenuItem();

...to choose from a directory listing which file the user wants...


JFileChooser fc = new JFileChooser("*.*");
fc.showOpenDialog(myFrame.this);


...and this is buffered into memory...


BufferedReader br = new BufferedReader(isr);
while ((line = br.readLine()) != null)
{
wholedata += line + "\n";
}


...and drawn on the screen.


Font myfont = new Font("Courier",Font.BOLD, 18);
TextLayout tl = new TextLayout(string, myfont, myfontrendercontext);
tl.draw(graphic, horizontal_position, vertical_position);


I was happy that in a couple of hours messing around I had created a program that actually did something useful.

source code:-

For a week or so now I have been trying to help out an associate who needs to demonstrate to potential clients that he can deliver certain specified capabilities in a program.

One thing he needs to demonstrate is that he can write a stand-alone program that will connect to a specific secure http server send a message to it, and retrieve a response. This doesn't sound too hard, and indeed it is not, if you are using the right tools. The right tools in this case being an up to date version of the Java software development kit.

Within the same evening of receiving the specifications I was able to write about ten lines of code that connected to the secure server, sent the supplied message (in XML format) and retrieved and uncompressed the response.

This satisfied me that the server was working properly.

I thought it would be a fairly easy matter to duplicate this activity within a Delphi program.

Unfortunately none of the components of Delphi 7 (which I run on my Windows 2000 laptop) support making SSL (secure socket layer) connections. I tried to install a version of CurlLib which is based on that handy Unix utility 'curl' that can retrieve almost any kind of file from any kind of server. Eventually I gave up as I couldn't figure out quite how to compile it all.

Thinking things would be easier if I was using a more up to date version of Delphi, I installed version 2005, running on my mum's new laptop, which is just about fast enough to make it usable. Sure enough it had all kinds of extra web components, but it took some time for me to cotton on that I needed to use the 'Indy' or Internet Direct components. Once I had worked this out it didn't take too long to come up with some code for connecting to a secure server. This worked for just accessing any old secure web site, but failed whenever I tried to connect to the actual server.

Trying to figure what might be wrong lead me down the path of investigating certificates - which are the bits of information that are stored on your machine and the machine you connect to, like ciphers, what let you and someone else communicate without anyone else being able to listen in, or impersonate one of you.

Having finally generated and correctly 'self-signed' my certificate, I found that it made no difference. So, I gave up on Indy and moved onto my final attempt which was a library named 'Synapse'. This was much easier to install, and could work even with Delphi 7. I got it connecting to normal web servers, but unfortunately it failed to connect to any secure servers that I pointed it at.

So finally here I am, having exhausted all obvious avenues to do something that I thought would be simple. So there is nothing left for me to do but sing the blues...

My delphi's not working

It just won't compile

And when I try to connect it

I end up losing my smile



Secure socket layer

Ain't my cup of tea

I made my certificate

And my private key



So now I give up

And call it a day

Can't talk with that server

No how and now way



Now there is a moral

To this sorry tale

Just stick to your Java

Or you're sure to fail!

A few months ago an aging laptop passed into my sole use, originally aquired by my father through his work, at trade price, before he retired. It is an IBM Thinkpad 660E, a sub Gigahertz pentium II with 6Gb of diskspace and 128Mb of memory, running Windows 98. After several years of use by my family, it was finally no longer needed as everyone now has their own laptop.

To start with I removed all the excess software and junk, then I put it to use as a testing server for ASP scripts, and developed my website on it (enigmaticeye.com)

Eventually I decided it was not much use running Windows 98, and thought about upgrading the operating system.

My first thought was to install some flavour of Linux. The main problem I faced was that I would need drivers for the wireless network card, which has a ralink chipset, drivers for which are only built in to modern distributions with a 2.6 kernel.

So I started with Ubuntu. Now I had never really experimented with live linux CDs, and I thought it would be a sinch. However, after half an hour loading the graphical installer, I finally gave up, and tried the text mode installer. I gave up on this after about an hour. Next I tried Mandriva, but faced similar problems. NetBSD and Slax I couldn't even get to boot. While I was trying these installations, I managed to download the full five disk set of Suse Linux, but found this was taking forever too.

Finally, I got the message, no matter how hard you try, you ain't gonna run brand new software on seven or eight year old hardware. So I tried a compromise, and installed Mandrake 10.0, a distribution a couple of years old, but which uses a 2.6 kernel. It was a bit sluggish, but there was hope. However, having installed it, I found it did not have ralink drivers built in, but that one was available to download. It had to be compiled though, and I soon realised that I did not have the kernel source code installed. The specific version I needed was unfortunately missing from the CDs, and unavailable on the web.

Admitting defeat, I have opted for Windows 2000 as my operating system of choice, having the advantage that plug in and play, no hassle, drivers are readily available, and it can run decently even on an old system like my thinkpad!

We have a family computer at home which everyone uses to send and receive email using outlook express. For some time I have pondered how people could get their email on their own various laptops.

Short of buying Microsoft Exchange Server, I don't really have an answer, but today we moved a step closer.

The inspiration came when my father and I were discussing where the email is actually stored - in database files within a special system folder - which we regularly back up as a matter of course. It occured to me that one PC could store its database files on another PC, over the network. I didn't know how possible this was, or what sharing violations might occur if both PCs tried to run outlook express at the same time.

My first port of call was the registry where I searched for the string "Outlook Express" and found it in

HKEY_USERS\S-1-5-21-2000478354-507921405-1957994488-1003\Identities\{E87DC317-98C4-40FB-B7BF-C1EE5C4E4411}\Software\Microsoft\Outlook Express

Within this was a very promising piece of information called 'Store Root' which, it was my guess, pointed to where the database files are stored.

All I had to do was change this pointer on the laptop to look across the network at the PC's outlook express database directory.

At first Outlook Express could not open the files, but when I shared it with Read-Write access, to my pleasure, it worked perfectly.

A little tinkering with my father on the PC and myself on the laptop proved that there were no real sharing problems with accessing the databases from two places at the same time.

We could not go as far as being able to send email from either computer, but being able to read emails in the large archive we have accumulated from either computer is quite a useful step.

I bought my PDA (Personal Digital Assistant) a couple of years ago, and use it to keep track of the appointments I have each month (as well as listen to music). At about the same time I bought a mobile phone that I could use as a modem via Bluetooth (a short range wireless connection) so the PDA could access the internet whilst I was out and about.

Add to this that I have a laptop and a desktop PC, each with its own calendar.

So far I have managed to organise myself by synchronising just the PC and PDA over a USB (wired) connection, updating the calendar on my laptop by hand, and never using the calendar on my mobile phone.

The problem is that recently I have become lazy about taking my PDA with me, meaning that I have to remember appointments, write them on scraps of paper or note them down in my phone temporarily and re-enter them on my PDA when I get home. This system (or lack of system) has lead to me forgetting at least one fairly important appointment.

It turns out that I can keep all four systems in tune with each other. Here is how:

• Use Palm Hotsync and USB link to synchronise Windows PC running Outlook and Tungsten T3
• Use Palm Hotsync plugin for iSync and Bluetooth link to synchronise Tungsten T3 and Apple Powerbook running Address Book and iCal
• Use iSync and Bluetooth link to synchronise Sony Ericsson T610 mobile phone and Powerbook...

I went for an interview for a job one aspect of which was web design, and was tested to see if I could write javascript validation for a form. Now, I suprised myself to find that I couldn't get a simple piece of code to work and do what was required when I was put on the spot.

The fact is, that although, in the past, I have played around a lot with javascript actions on forms, I eventually lost enthusiasm for client side scripting altogether. (One example of client side scripts you can see at the site http://www.nascroydon.org.uk click on Newsletter archive and choose an item from one of the pull down lists.)

My big problem with client side javascript is:

• It doesn't work on all browsers, leaving users potentially unable to use your site
• Malicious users can override your validation by recoding the script, so to be secure you have to code the same logic server side anyway

Now it has been taught to me that there are good uses for client scripting, for example, warning the user before they delete a record, to make sure they haven't done it by accident.

e.g.

onClick="return (window.confirm('are you sure'));"

What I have taken to heart is that a page must function whether or not javascript is enabled, but that it can provide an enhancement to the users experience.

Coming back to the question of how to quickly check whether a field has been filled in on the client side, this can be done in the onClick event of the submit button, which must return true or false depending on whether the input is valid.

In the case of my interview, the code I typed was:

onClick="if (form1.textfield=='') window.alert('you must enter some text');"

the correct code would have been:

onClick="if (document.form1.textfield=='') window.alert('you must enter some text');"

What the incident really brought home to me is how much I depend on using a search engine to find snippets of working code, without which it is easy to forget the exact keywords and syntax required.

My mother has asked me about getting a laptop she can use to do her univeristy work on, while my father is using our family PC (which he spends a lot of time on now he is retired). All she needs is to be able to browse the web, run interactive CD-Roms, and write essays using Word.

How does this translate into a technical specification?

The ability to run Windows XP I see as the main requirement, as many software/multimedia developers use 2000 or XP as their target platform.

Looking at my nearest large mail-order supplier Novatech even their cheapest laptops claim to be Windows XP compatible, but I am not convinced that they will be really responsive given a processor speed of less than 2 GHz. I would opt for a little more memory than the bare minimum to help speed things up.

Assuming I go for an own-brand Celeron range, the other things I would like are:

• DVD Writer
• 54G Wireless

The former is simply because its the latest storage medium, even though its not strictly necessary, it would seem to be worth the minimal extra cost, as upgrading optical drives on a laptop at a later stage is not something I'd contemplate.

The wireless capability is important so my mother can use it in any room in the house.

Finally comes the choice of software. Having the operating system pre-installed would be ideal. After that, Office educational version would seem like a good choice for the purpose intended.

Once all these options are figured in, the final price tag is a little higher than expected, but overall it is a system I am happy to recommend to my mother to suit her needs.

It's been a while since I had a look at Redhat Linux (now superceeded by Fedora Core), but I thought I'd make a fresh minimal install on a virtual machine, running on my PowerBook Laptop.

Why do I like Redhat?

• Well it has a sophisticated package installation system, using RPM files, which has since been copied by other flavours of linux.
• The installation was one of the first to be very simple out of the box, easy enough for mere mortals to use, and again, this is something that has been copied by subsequent linuxes.
• You could actually buy it in a shop, and it came with a limited free technical support. Ditto my other comments.