Steffen's Tech Blog

In Mac OS X you can take a screenshot of the complete screen by pressing Command-Shift-3 and a selection of the screen by pressing Command-Shift-4. This is usually sufficient enough, but if you try to use this key combination to capture a screenshot of a movie running in the Mac OS X DVD Player you will be surprised to find out that this doesn't work. The same is true for the built in Grab Application. If you still want to do capture a picture from a DVD you could use the screen-capture shell utility in the Terminal application - as described in several webpages. But if you would like something more convenient you could use an application such as Jing ( http://www.techsmith.com/jing/ ). It allows you not only to take a picture even from a movie running in the DVD Player but also to make a short videos of the your screen and provides several options to edit, save and share this pictures and videos afterwards. There is a Free version available a...

I am a fan of the free open source format 7z (see  http://en.wikipedia.org/wiki/7z ) for data compression and encryption. With keka ( http://www.kekaosx.com/en/ ) there is a nice, simple GUI application available for Mac OS X.

Recently I needed to combine two PDF documents that I created with the TurboScan App on my Iphone (file sizes 528.5 kByte and 421.9 kByte and was searching for free options I can use with Ubuntu Linux. I found the following options: The web service  http://www.mergepdf.net/ : Usability: Easy; excellent for merging PDF files Functionality: no other functions available File size of the merged file: 950.1 kByte The free online PDF editor PDF Hammer  http://www.nitropdf.com/free/hammer/index.htm . Usability: almost as easy as mergepdf Functionality: other functions available File size of the merged file: 949.8 kByte The Linux command line   pdftk too lkit:  http://www.accesspdf.com/pdftk/ Usability: follow examples on the webpage; easy if you are comfortable with the command line Functionality: other functions available File size of the merged file:  949.8 kByte The open source PDF editor PDFedit  http://sourceforge.net...

As my 500GB Time Capsule has reached the limits (my Macbook and the iMac of my wife used it as backup destination for Time Machine ), I decided to buy another backup drive and settled with the Western Digital WDH1NC10000E My Book World Edition 1TB NAS external drive. The main advantage (besides the price: I bought it fo r EUR 146,95 (incl. VAT and free transportation) for me was that I could easily connect it to a free Ethernet port of my Time Capsule - at least that was what I did expected. But after I connected the My Book to my network as discribed in the My Book manual, I had to discover that although it was available in the finder and I could manually copy files to it, it wasn't available in Time Machine as a back up destination. Furtunately obvioulsly others experienced this problem before and after some googling I came to the solution described in the post "Time Machine backups on network shares in Leopard" from Florian Kruse. Following the steps described the...

I tried Dropbox - a cool file-synchronization service for Windows, Mac, Linux and the Web - after hearing about it on the Macworld Video Podcast Episode from Jason Snell from Feb 13, 2009 and loved it since. Dropbox allows you to sync (and - if you want share) up to 2GB of your files and folders automatically (and for free!) simply by dragging and dropping them into the Dropbox folder that will be created by the application (by default under your home directory). If you need more space you can buy 50GB of storage for currently US$99/year. I'm impressed how easy and fast the web-based synchronization works and was amazed that it works cross-platform - even an Ubuntu repository is available. I use it now to synchronize a few files I often need on my Ubuntu desktop, my macbook and my wife's iMac. If it works as reliable as it has done in the first days I am using it and if there will be a more cheaper storage plan version (e.g. 25GB for US$49/year), I might use it even to back...

In the last months I have spent some time trying out different GUI toolkits for Python that are cross-platform (Linux, Mac OS X and Windows). I settled with PyQt . It combines Nokia's Qt cross-platform application framework with Python so you get all the power of Qt with the simplicity of Python. Other Desktop GUI frameworks I have tried are: the Tk GUI development library included in most Python distributions wxpython a blending of the wxWidgets C++ class library with Python PyGTK to use the GTK+ library Others (such as .NET using IronPython ) are not running equally good on Linux, Mac OS X and Windows as they favour Windows. From the frameworks above, PyQt  seemed the one with the most active development, the most easy usage and the best documentation. Like Qt, PyQt V4 (its newest version) is available under a variety of licenses including GNU GPL (V2 and V3; today Qt Software announced that Qt V4.5 will also be available under LGPL). If you want to write commercial applicat...

Did you ever want to download Web videos from sites such as YouTube or others (such as http://www.vidohe.com/sites.php )? Firefox 3.0 together with the free Firefox extension DownloadHelper makes this very easy (see the DownloadHelper homepage for more details). DownloadHelper even provides a Video Conversion feature to allow background conversion of the downloaded video to the format that you like (e.g. from FLV to a format that can be used by iTunes e.g. to load on your iPod or iPhone). This feature relies on FFMPEG available on your system (for Linux or Mac), which can lead to conversion failures as the version of FFMPEG may not have been compiled with the features required by the chosen conversion parameters. You can therefore recompile FFMPEG by yourself with the required features. Note: With Ubuntu 9.10 - the Karmic Koala - there is no need to recompile FFMEG. It just works fine. As an alternative, you can use an external application such as MPEG Streamclip ...

Two weeks ago my MacBook wouldn't start because of a hard disk defect. As the Macbook still was within the warranty period, I took it to the nearest Apple authorized service provider A.S.T.I. GMBH AGENTUR FÜR SYSTEME (that I have found via http://www.apple.com/de/buy/locator/index.html ), where they replaced the HD. At home, I restored my Macbook HD content (that furtunately had been regularly backed up via Time Capsule) with the following steps (based on http://support.apple.com/kb/HT1177 ): Install the system from the Mac OS X 10.5 Leopard DVD Restart the Mac Connect Time Capsule via an Ethernet cable with the Macbook Click "From a Time Machine backup or other disk." when asked if you want to transfer information from another Mac or volume (in the Do You Already Own a Mac?" window). Click Continue Select Time Capsule when it appears as a Backup Volume and click Continue The Macbook starts to check the Time Machine backup and the "Transfer Your Information...

Recently, I spent some time to search for free, open-source alternatives for commercial mathematics programs such as Matlab and Mathcad. By far the most promising software I have found was Sage. Sage combines the power of many (currently 71) existing open-source packages into a common Python-based interface. It can be used to explore mathematical constructions in algebra, geometry, number theory, calculus, numerical computation, etc. The combination of proven open-source packages (including excellent Python packages such as Numpy, Matlibplot, Scipy and Sympy) and an excellent web browser based entry of formulas and plots in worksheets called notebooks. The usage of Python as the glue that holds all packages together provides several advantages. First you have the full power of python available in Sage. Second, you don't need to learn another specialized script language that you would otherwise not need. Excellent screencasts together with good tutorials and documentation pages p...

Finally, I decided to buy the newest version of Mac OS X. The main reason was that I liked to have a professional backup solution for my macbook especially after the trouble I had before on my Windows desktop (see my previous post from April 2008 ) and Time Machine together with Time Capsule seem to be exactly what I was looking for. The installation of Mac OS X was smoothly. Everything worked as expected. Even my synchronization via the python rsync script worked. Time Machine setup together with Time Capsule are really amazing simple and effective. There are many more nice little features in Mac OS X Leopard. Check out http://www.apple.com/mac/ for more. In my point of view, it is definitely the best operating system I know. Once more, Apple products fulfilled my expectations and are worth their price.

11 days ago my boot hard disk crashed during some Norton Antivirus scanning in Windows XP. My desktop PC is a Fujitsu-Siemens Computer Scaleo T A64 XP 50 AM2 0 2,0GB bougth in 2006. I had Windows XP installed on the original Sigate 320GByte disk that contained also all my data (as I wanted to use the same files from both Windows and Ubuntu and Windows can't write on the Ubuntu file system but Ubuntu can write on the Windows NFTS format). In addition I had installed a 400 GByte harddisk with a backup partition and my Ubuntu installation. The bios couldn't find the Sigate disk any longer and as this disk contained the boot loader - neither the Windows XP nor my Ubuntu 7.10 did start. An clicking noice confirmed that there was a serios problem with the Sigate disk. What to do? As I have a three-year service contract from Fujitsu-Siemens I first contacted the Fujitsu-Siemens service via the service phone I found under http://www.fujitsu-siemens.com . They aggreed to send somebody...

Ever considered to make your Ubuntu installation even more secure? There is an excellent chapter available in the official Ubuntu documentation called "Keeping Your Computer Safe" that is worth to read. I used its sub chapter "Set up a firewall" to install the firestarter package - an Open Source visual firewall program that combines ease of use with powerful firewall features. To understand its basic features and how to use them you can read the quick tutorial from the Firestarter Online Manual . After completing the start wizard, some services that you might have on your machine such as a web server or a SSH server will not be reachable any longer from the outside because the default configuration set up provides strong protection against incoming intrusions. E.g. the connection from my Macbook via SSH to my Ubuntu machine wasn't possible any longer and therefore my rsync script described in my previous post " Synchronize files between a Macbook and an...

If you are using the Mozilla Firefox Web browser, you can also use ScribeFire to post your blog easily from within the browser. It allows you to drag and drop formatted text from pages you are browsing, take notes, and post to your blog. You can even add easily labels to your post. Everything works very fast. As Firefox is a cross-pattform browser, you can use it on Linux/Mac/Windows. You can read more about ScribeFire on http://www.scribefire.com/ where you can also find the link to install it from the Mozilla Add-ons site. Somehow the length of the posts seem to be limited as I have noticed that longer posts (such as my post from March 4, 2008) will be not loaded completely in the ScribFire Editor, but I haven't found any information about the maximum allowed length of a post.

Another easy way to post a message to Blogger is using Google's Dashboard Widget for Mac. Its very basic text formating ( bold and italic ) should be sufficient if you want just post some short lines to your blog without advanced formating, links, images, media files, spelling check. In that case it is much faster than having to start first a browser or a full-blown desktop application. What I am missing is the feature to add labels for the post, so if you want to add labels you need to do this later directly in Blogger. Blogger Dashboard Widget for Mac is available from http://www.google.com/macwidgets/index.html .

As I did use different computers at home (mainly Ubuntu and Mac OS) to write the post, I did appreciate that the document was always online although I had sometimes (especially at the end, when the document was already quite big) problems with lost connections that caused loss of some changes. I didn't experienced this before with smaller documents so I assume that either Google Docs Writer is not yet capable of handling long documents having pretty nasty HTML code inside (see the point about the code listing below ) or there had been connection problems caused by server problems. So I guess if I am about to write another similar post I might want to try a desktop application such as OpenOffice (with Sun Weblog Publisher extension) or I might want to separate the a bigger topic into several smaller posts (which would probably the best). I shouldn't use the Styles "Header 1" or "Header 2" from Google Docs as they let to too big headlines in the blog po...

Have you ever considered mirroring/synchronizing your important files from your Mac to your Linux machine to decrease the risk of data loss because of a hardware crash? One very effective way to do this is using two open source tools available on your Mac and your Linux machine called rsync and ssh. This document will lead through the necessary steps. The main reason for this document was to have a reference for myself as it wasn't trivial. Maybe it can be helpful for others. As a precondition, it is assumed, that you have two computers that are connected via a network. I am using a Macbook with Mac OS X 10.4 Tiger and an Ubuntu PC with Ubuntu 7.10 Gutsy connected via a WLAN where I have verified all the steps. Some of the steps described are Mac / Ubuntu specific. Most information should be valid for other operating systems where ssh and rsync can be installed (e.g. other Linux distributions) but you might check out the distribution specifics if something should not work. ...