Software Engineering blog » Week 2 http://softwareengineeringblog.com Software - Art Fri, 03 Feb 2012 14:43:00 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Describe an OS http://softwareengineeringblog.com/http:/softwareengineeringblog.com/academic-work/describe-an-os/43 http://softwareengineeringblog.com/http:/softwareengineeringblog.com/academic-work/describe-an-os/43#comments Wed, 25 Nov 2009 00:22:14 +0000 Laszlo http://softwareengineeringblog.com/?p=43 I have a small company, where we decided to choose Freebsd as the server platform. We don’t have too much money to spend so the price was one of the main reasons. We needed a server platform which can host web services reliably. Although my partners and me also are IT experts, we wanted to spend the least possible time with the operating system. We wanted to concentrate on the web development instead. When we started the company, Windows wasn’t reliable at all. We hadn’t got enough time to support it – not mentioning the price of a Windows server with Microsoft or Oracle SQL server. LINUX was an obvious choice. After fighting with the problems in several LINUX distributions (SUSE, Slackware), one of my friends asked: Why don’t you try Freebsd? I never had any problems with it! Upon his suggestion we installed Freebsd on a server without any previous experience. We experienced that Freebsd completely fulfilled our needs, it adequately performs as a web server which needs no maintenance. We usually reinstall our servers when we need a full version upgrade, apart from it our Freebsd servers were running all time without interruption. These “servers” were desktop computers without any server features! On a workshop SamoaTel ISP wrote: “And, in case you missed this, FreeBSD is extremely stable, particularly under heavy load. ” (http://ws.edu.isoc.org/workshops/2006/ccTLD-Samoa/day1/freebsd/whyfreebsd.html, 2006) I think Freebsd have more advantages than disadvantages. Once it is set up properly – which is not always easy in case of exotic hardware devices – it runs till the end of the hardware’s life. Bob Bruce and Murray Stokely also thinks that Freebsd is a very realiable operating system with an uptime what can be measured in years (http://people.freebsd.org/~murray/bsd_flier.html,n.d). I also experienced, that Freebsd is a very secure operating system. We only had succesfull attacks from hackers because of our own misconfiguration. Almost all information sources tells you a lot about security in Freebsd because it’s one of the most important features of this operating system. It has a very thorough release engineering process to minimize the chance of the security leaks in the code. Freebsd issues a regular Security advisory newsletter to advise the administrators. Jail system ensures, that you can run any application in a “sandbox” wihout affecting the performance. It ships with three enterprise level firewall and strong security audit features! Another very important aspect is the Ports tree. This Ports three is a hierarchically organized software collection. The Ports tree itself only contains a small stub file with the location of the source code of the software. When you need a new application, you can simply navigate in the hierarchy to it – or you can also use a search function – and type in a make install command. Freebsd will download the source, compile it, configure it and the application is ready to use. I have to mention that it’s hard to find better references about freebsd, than Freebsd Handbook. The FreeBSD Documentation Project (2009) FreeBSD Handbook [Online]. Available from: http://www.freebsd.org/doc/en/books/handbook/ (Accessed: 11. October 2009). If I could modify just one element, I’d improve the support of Virtualization. Although Sun’s VirtualBox is available in Ports, Freebsd’s competitors usually offer more choices. Rogier Dittner,David Rule (2007) The best damn server virtualization book period. Burlington: Syngress Publishing Inc., pp 39-40 published a detailed comparison table about virtualization solutions and they only list Freebsd as a guest OS. This definitely needs to be improved. Reference list: Bob Bruce, Murray Stokely (n.d) FreeBSD vs. Linux vs. Windows 2000 [Online]. Available from: http://people.freebsd.org/~murray/bsd_flier.html (Accessed: 11. October 2009) Rogier Dittner,David Rule (2007) The best damn server virtualization book period. Burlington: Syngress Publishing Inc., pp 39-40 SamoaTel ISP (2006) Why Did We Choose FreeBSD? [Online] Available from: http://ws.edu.isoc.org/workshops/2006/ccTLD-Samoa/day1/freebsd/whyfreebsd.html (Accessed: 11. October 2009) The FreeBSD Documentation Project (2009) FreeBSD Handbook [Online]. Available from: http://www.freebsd.org/doc/en/books/handbook/ (Accessed: 11. October 2009)

 

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]]> http://softwareengineeringblog.com/http:/softwareengineeringblog.com/academic-work/describe-an-os/43/feed 5 Linux operating system http://softwareengineeringblog.com/http:/softwareengineeringblog.com/academic-work/linux-operating-system/36 http://softwareengineeringblog.com/http:/softwareengineeringblog.com/academic-work/linux-operating-system/36#comments Wed, 11 Nov 2009 23:28:47 +0000 Laszlo http://softwareengineeringblog.com/?p=36 In 25th of August, 1991 the history of Linux has begun with a post to the MINIX newsgroup by Linus Torwalds: “Hello everybody out there using minix – I’m doing a (free) operating system (just a hobby, won’t be big and professional like gnu) for 386(486) AT clones. … PS. Yes – it’s free of any minix code, and it has a multi-threaded fs. It is NOT protable (uses 386 task switching etc), and it probably never will support anything other than AT-harddisks, as that’s all I have :-( .” (http://www.cs.cmu.edu/~awb/linux.history.html, 2009). Some years has passed, so now we can say, that those words changed the history of computing. It’s interesting to read, that this operating system wasn’t intended to be a professional one, it wasn’t intended to be a portable one. It was simply a tool for Linus for practicing C language and the 80286 processor’s architecture. Although there was a keyword in his post: free. Linux was free and remained to be free. Anybody was allowed to contribute and thus thousands of developers started to use it. For years, Linux was the playground of the programmers. I myself also used it a lot years ago just for the sole purpose of trying out many different programming languages. In those years Microsoft was dominant on the PCs and Unix was dominant on the servers. All commercial operating systems source code was closed. The code contained errors. I do believe, that the real programmer likes to solve problems (solve problems better then other programmers). Many of them didn’t learn programming in a school, they became programmers because they found that it’s a challenging new industry. It was more difficult to find education resources and participating in development of an operating system was – and still is a very challenging task. Parallel with the evolution of Linux the revolution of the Internet became faster and faster, what made a huge need for web servers and other services on the Internet. Developers made free servers and community started to use them, test them and even patch them and published the patches. The word “free” makes possible for developers to participate, but it’s not enough for organizations. Most organizations need stability and support. Many told that Linux had and has greater stability than Windows for example, but there was a big difference: Windows had commercial support but Linux hadn’t. According to Redhat.com (http://www.redhat.com/about/companyprofile/history/, n.d), in December, 1997 they introduced Redhat 5.0 and the commercial phone support for Linux. This meant, that any organization was able to turn to a respected and trusted company for support and they knew, that they are not alone if they cannot solve a problem with their operation system. Programmers can play but companies cannot. On the other side, selling commercial support for Linux seems to be a Win-Win situation. Organizations need it and companies selling commercial support can attract investors and make profit. Kenneth Hess on Linuxplanet.com wrote: “The idea of fixed yearly support costs is an appealing one. Knowing exactly what your desktop and server support costs will be for the coming year makes it much simpler to create a budget. Purchase a three-year subscription and enjoy a 10 percent discount on the price. Imagine accurately planning a three-year budget — that’s the stuff of bean-counters’ dreams!” (http://www.linuxplanet.com/linuxplanet/reports/6681/1/, February 25, 2009). In my opinion commercial support and the huge number of available applications are the key for Linux’s success amongst commercial organizations. Reference list: Kenneth Hess (2009) Commercial Linux Support Showdown [Online] Linuxplanet.com. Available from: http://www.linuxplanet.com/linuxplanet/reports/6681/1/ (Accessed: 11. October 2009) Linus Torwalds (n.d) LINUX’s History [Online] Carnegie Mellon School of Computer Science. Available from: http://www.cs.cmu.edu/~awb/linux.history.html (Accessed: 11. October 2009) RedHat Inc. (n.d) Red Hat History [Online]. Available from: http://www.redhat.com/about/companyprofile/history/ (Accessed: 11. October 2009)

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