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What is JeOS?
Generic operating systems such as Microsoft Windows manage the various hardware components in the host system and provide a stable and consistent set of interfaces and libraries to support a wide range of applications. Just Enough Operating System (JeOS) is a departure from this concept of a single operating system supporting all applications to a system where the operating system includes only those components required to support a specific application and third party components contained in the application. The fact that most servers today run just a single application, such as a database, file/print server, or exchange server raises the scope for JeOS. For instance, an exchange server does not require ActiveX control. Generic operation systems still load the installed Active X controls, whereas JeOS eliminates it.
A typical JeOS consists of:
- The operating system core of Kernel, Virtual Drives, and Logint
- Minimum maintenance tools for the operating system
- Minimum user space tools
- Packages repository, either DVD or Network based
Image Credit: flickr.com/Kevin Jarrett
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Memory and Performance
The biggest advantage of Just Enough Operating System (JeOS) is that it makes the appliance smaller. The proliferation of appliances and devices over the years have lead to the traditional general purpose operating systems growing in size and complexity by the addition of interfaces, libraries, and functions to support such ever-increasing applications and devices. Such an ever-expanding operating system becomes bloated, complex, and far less secure, and requires about 1 GB RAM minimum just to run as it activates the various unnecessary services loaded into the memory. The huge footprint requires constant patches.
JeOS helps reduce the size of the operating system by loading only what is required for the application to run. This reduces the memory usage and ensures a smaller footprint, enabling running of more instances per server and improving performance.
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Just Enough Operating System (JeOS) increases security manifold when compared to a full general purpose operating system. Removal of unnecessary packages reduces the number of potential vulnerable components such as the browser, significantly reducing the vulnerabilities and patches associated with such components.
JeOS, by reducing the size of the operating system, lowers the number of packages and patches that require management and thereby reduces support costs.
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Just Enough Operating System (JeOS) forms a part of Virtual Appliance that allows focusing time on the core business activity instead of the operating system.
Virtual Appliance is a pre-built, pre-configured, ready-to-run enterprise software application that runs on a visualization platform. It comes with the JeOS operating system and application within the virtual machine. This eliminates all headaches associated with deploying, patching, and managing the OS.
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The disadvantages of Just Enough Operating System (JeoS) are few. A major practical difficulty is the possible non-installation of some essential components to run the application owing to oversight, lack of knowledge about the need for such component, or owing to non-availabity at the time of installation. This makes the application inoperative or unable to load many essential features.
Although JeOS enjoys clear benefits over the traditional generic operating systems, it works best only when a single server runs only a single application. The traditional generic operating system still works best when the system is put to a wide range of possible uses at the same time or intermittently.
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- SUSE Linux Enterprises. Just Enough Operating System (JeOS). http://www.novell.com/products/jeos/. Retrieved 05 October 2010.
- Open Solaris. Just Enough Operating System. http://hub.opensolaris.org/bin/view/Project+jeos/WebHome. Retrieved 05 October 2010.
- Krishnamurthi, Srinivas. Get Juiced! http://blogs.vmware.com/console/2007/07/get-juiced.html. Retrieved 05 October 2010.