Archives For Linux

dCore Linux is a minimal Linux system based on the Tiny Core Linux system. Like Tiny Core Linux, dCore loads its file system entirely into RAM, which should provide good performance in large network emulation scenarios running on a single host computer.

dCore Linux allows users to install additional software from the Debian or Ubuntu repositories, instead of using the pre-built (and often out-of-date) TCE extensions provided for Tiny Core Linux. This should simplify the process of building network appliances for use in a network emulator, as you will not need to compile and build your own extensions, or use out-of-date pre-built extensions.

dCore Linux is designed to run as a “live” Linux system from removable media such as a CD or a USB drive but, for my use, I need to install it on a hard drive. Currently available instructions for installing dCore Linux onto a hard drive are incomplete and hard to follow. This post lists a detailed procedure to install dCore Linux on a virtual disk image connected to a virtual machine. I use VirtualBox in this example, but any other virtual machine manager would also be suitable.

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Previously, we installed the CORE Network Emulator from source code and installed the network services used by CORE. Now, we want to run a simulated networking scenario and modify the configuration of the quagga routing daemon on one or more virtual routers.

To do this, we open a shell to the node and start the vtysh shell so we can use the quagga command-line interface. But, the quagga vtysh shell starts with a mostly blank screen displaying the text “(END)”.

vtysh shows blank screen with (END) text

vtysh shows blank screen with (END) text

We have to enter the “q” key to get back to the vtysh command prompt so we can enter the required configuration command. Every time we enter a vtysh configuration command we see the blank screen with “(END)” again.

Read on to learn how to fix this annoying problem.

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When I started a CORE Network Emulator simulation scenario on my computer running the Xubuntu Linux 13.10 operating system, I encountered a few issues that I needed to correct.

The Ubuntu Network Manager drops my WiFi connection after I start the CORE simulation scenario and the Terminal does not start when I double-click on a node in the CORE canvas.

This post describes how I worked around the WiFi connection problem and resolved the Terminal problem.

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TinyCore Linux is very suitable for devices like routers that require a higher level of security. All changes made to a running TinyCore Linux system exist only in system RAM and are lost when the system restarts or is shut down. Viruses or file corruption can be removed simply by rebooting the system.

When used as part of an open-source network simulator, the TinyCore Linux appliance can be restored to a base configuration every time it is started. This means the same appliance can be reused in new simulation scenarios without having to clear configurations that may be left over from a previous simulation effort.

However, in some cases we may want to save the configuration changes we make. For example, we may wish to have a basic network configuration working at start time. Or, we may wish to build a complex simulation scenario that will be re-used by other researchers. In this post, we discuss the TinyCore Linux system architecture and how to save configuration changes.

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I’ve been using Parallels Desktop for Mac to run a Debian Linux 6.0 virtual machine. I wanted to install the Parallels Tools in the Debian virtual machine so I could take advantage of better integration between the Linux virtual machine and the Mac OS X host computer.

It wasn’t as straightforward as I thought it would be but it wasn’t hard to figure out. I described the procedure I used below.

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