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Welcome to my blog. This is mainly about IT, information management and Cyber Security with occasional forays into general technology, science and maybe even politics and beliefs.
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There are 301 pages currently on this site. 235 blog posts, 60 knowledgebase pages, 6 about pages and 0 project pages.
Latest posts and knowledgebase articles
Development Virtual Machine (VirtualBox)
I’ve been thinking ahead to a change of job recently. Knowing that I’ll be getting a new Windows based laptop and needing to have development capabilities and having developed a taste for Linux 😉 I’ve used my favourite VM tool [VirtualBox][1] (now owned by Sun) to create a sparlkly new OpenSUSE 11.0 virtual machine complete with Apache, MySQL, PHP, etc. as well as office tools such as Open Office, mind/concept-mapping and diagraming applications.
Keeping information secure but accessible across platforms
One of the issues with Linux is that I can’t use it under all circumstances. In particular I usually have to work with Windows at work. So I need cross-platform tools, especially now that I also make extensive use of a smartphone/PDA. So here is a timely post – with the number of people in UK government departments carelessly loosing private or secret information, how do we keep this stuff secure while still being accessible from different platforms?
Changing backspace to go back through history (FireFox for Linux)
Us old-time Windows bods get used to our keyboard shortcuts I’m afraid. One of the most useful is using the backspace key in the browser to go back through the browsers history. Unfortunately, this is not the default under Linux (alt-left arrow is the default). FireFox has an easy way to fix this. Put “about:config” in the address bar and “backspace” in the search entry. You should see the entry “browser.
What did I install? (For OpenSUSE)
One thing that I didn’t get around to doing since I moved from Ubuntu was to work out how to make a note of what has been installed. This is slightly complicated by the fact that you can install stuff straight from an RPM file as well as through YAST (from the repositories or 1-click links). Well, I finally got round to working it out and here is a summary. To see what you have done with the YAST installers, just look at the log!
What Linux system files might need editing?
Whilst great strides have been made by the Linux community to provide GUI’s for many tasks, it is still a command line driven OS at it’s heart. This, of course, is one of its strengths as everything can be scripted too. However, for none IT techies, it is very daunting. Here I’m listing some of the system files I’ve had (or at least wanted) to change by hand. It’s a very quick reference, largely for my own benefit should I need to rebuild my system.
Showing a less than symbol in a Blogger post
This took me ages to sort out so here is a reminder. If you want to post a less-than symbol in a Blogger entry (for example in some code or a math formula), you cannot use the standard HTML entity “<” as Blogger cannot cope with it for some reason. Instead use the hexadecimal equivalent “& # 60 ;” (NB: I’ve put spaces in so that Blogger doesn’t turn it back into a symbol!
What stops me finally parting company with Windows
Will I ever be free of Microsoft? Well, unlike many people I’m not really evangelistic about this. I’ll use whatever gets the job done properly. My main reason for ditching Microsoft products is due to their overly restrictive and greedy licensing without really giving real innovation in return. So why can’t I escape? Well one of the main reasons is that I am constantly faced with Microsoft products through my job as an IT consultant.
Update one table using data from another
If you want to update tbl1 with information from tbl2:
Welcome
I’m afraid that his is likely to be a pretty random collection. I will add stuff here that I come accross on the web that I think may be useful at some point. I will also add things that I discover as I’m writing stuff.
Cannot directly use the IF function on a MySQL query that uses GROUP BY
Cannot directly use the IF function on a query that uses GROUP BY. This tip provides an alternative that is cross-db. It is extracted from: http://surfnet.dl.sourceforge.net/sourceforge/souptonuts/README_mysql.txt SQL Characteristic Functions: Do it without if, case, or GROUP_CONCAT. Yes, there is use for this … if statements sometimes cause problems when used in combination. The simple secret, and it’s also why they work in almost all databases, is the following functions: sign (x) returns -1,0, +1 for values x < 0, x = 0, x > 0 respectively abs( sign( x) ) returns 0 if x = 0 else, 1 if x > 0 or x < 0 1-abs( sign( x) ) complement of the above, since this returns 1 only if x = 0 Quick example: sign(-1) = -1, abs( sign(-1) ) = 1, 1-abs(sign(-1) ) = 0 Data for full example:
Defaulting optional parameters
If you have a function that takes an optional parameter – e.g. function blah($xx,$yy='Default',$zz){ …. You can use the function and ensure that the optional parm always takes the correct default (even if the definition changes) by passing a NULL to it. e.g. … $mydate=blah($something,NULL,$more); …
Fast storage using tmpfs
Here is a link to an article on using tmpfs (and the commonly pre-defined /dev/shm mount for tmpfs) as a high-speed, in-memory filing system. This is very handy for small-ish amounts of data in files that get a lot of access. Just remember that you will loose it if the host crashes! You can use this for SqlLite database files too. [Create turbocharged storage using tmpfs][1] [1]: http://kevin.vanzonneveld.net/techblog/article/create_turbocharged_storage_using_tmpfs/
Update on FreeOTFE
Thought I would add a quick update on using FreeOTFE under Windows and PocketPC. I tried it under Windows on a different PC and it does indeed work OK though it is nowhere near as polished as TrueCrypt. I’ve also tried again a few times on a PocketPC with limited success and I think I know what is happening. Firstly, you must install FreeOTFE for PPC into system memory and not on a storage card – not terribly surprising really.
Living with Firefox
I use Firefox all the time. Both with Windows and Linux but I don’t like the fact that it assumes that you are using Gnome under Linux and doesn’t really play nicely with KDE. Thankfully there are a few things you can do. To get printing to use KPrinter (the default KDE print dialog). Choose the printer called Postscript/default and then change the command that is run to kprinter –stdin. Now, whenever you print to that printer, you will get the KDE standard print dialog where you can choose the printer (most importantly, output to PDF) and change the settings.
One command system update (Without password)
Here’s a very handy tip about configuring SUSE to run a full update from the command line without requiring a sudo (and hence a password). [One command system update (Without password)][1] [1]: http://fnmueller.wordpress.com/2008/03/02/one-command-system-update-without-password/
