Posts Tagged ‘Tech Tips’

A Technical Support FAQ: Testing serial ports in RS-232 mode

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Question:   How do I go about testing serial ports in RS-232 mode?

Testing Serial PortsAnswer:   For DeviceMaster® products:

Test the serial ports using the Test Terminal application in PortVision® DX (or PortVision Plus) and the Loopback plug provided with the DeviceMaster.

If you need to create a loopback plug, you may download the instructions HERE.

Instructions for testing serial ports:

Stop all applications that may be accessing the ports such as RAS, RRAS or any faxing or production software.  See the appropriate manuals for instructions on stopping these services or applications.  If another application is controlling the port, or if the driver had not been properly configured, then Test Terminal will be unable to open the port and you will receive an error message.

Remember to restart the application once testing of the ports has been completed.

Testing serial ports – the Comtrol ports:

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SERIES: Linux Support at Comtrol – Part IV

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UPDATE: Linux Support at Comtrol – Part II: Six Months Later

Linux Support

– Nick Thompson

It’s been six months since our first Linux post here at Comtrol, and I thought I’d give an update as to what’s been going on with Linux support here at Comtrol.

Kernel (not Distribution) Specific Support Continues:

Our support for the kernel, and not specific distributions, continues.  We believe this allows us to offer the best and most wide-ranging Linux support possible.  We have been able to support many customers with very niche distributions, and even a few who built their own distributions using LFS (Linux From Scratch) using this approach.  We have been able to support incredibly non standard distributions for companies and other organizations that we would not have been able to with a distribution specific approach. We will continue to operate this way, supporting as wide of a range of Linux as possible.

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SERIES: Linux Support at Comtrol – Part III

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Leveraging older PC hardware to perform daily tasks using Linux and Comtrol hardware

All too often, older PC hardware is thrown out merely because of it being unable to keep up with commercial operating system(s). Comtrol products, used together with the Linux operating system and older PC hardware you may have been considering throwing away, can be leveraged to perform daily tasks without the expense of a new PC being purchased.  This relates not just to Linux and it’s inherent ability to function well on older PCs, but also specifically to the Comtrol’s RocketPort® and DeviceMaster® hardware itself, and the design put into it.

– Nick Thompson

The Linux kernel is written in a manner wherein it can be compiled to squeeze every bit of performance out of the PC it’s running on.  When used with a Comtrol RocketPort or Comtrol DeviceMaster, the older PC runs as fast as it can for two reasons. The Linux kernel is compiled to squeeze performance, and the RocketPort and/or DeviceMaster are smart devices – they do not force the PC to put forth any of its computing power to run the devices, unlike ‘dumb’ multi-port serial boards which are essentially standard serial ports slapped onto a PCI board.  These take resources to run, and let’s remember we’re working with an older system here.  We can’t afford to use those resources, or the PC may be too slow to perform the task it has been selected for.

Pre-build vs. Compiling your own: Kernel issues to be considered on older machines  
One very nice thing these days within the Linux community is the fact that you can now download distributions which are designed from the get-go for older machines.  They will save you the trouble of installing a standard Ubuntu, Fedora, Suse, etc. and having to then re-compile your own kernel.  This obstacle is the biggest in squeezing every bit of performance out of older machines. (Again, the RocketPort – because of its ASIC processor – and the DeviceMaster itself take the load of the standard serial ports that a ‘dumb board’ would put onto the machine, and offload that onto the Comtrol RocketPort or DeviceMaster. This saves CPU cycles and RAM for the operating system and the task at hand.) There are many distributions out there at the moment that do this.  One I would recommend is Puppy Linux, though again there are many and much like with standard Linux distributions.  You’ll want to select one that uses the package management system you are used to, that has the features you want/need when planning an installation on an older PC with Comtrol products.  You can find links to various resources related to such things as Linux distributions that are good for this purpose at the end of this post.

Linux Comtrol RocketPort DeviceMaster  Untitled-1Linux Comtrol RocketPort DeviceMaster

Don’t throw away that Pentium II just yet! 
This post is not theoretical. I speak with customers who are using a Pentium II 450 megahertz system (or similar) to accomplish tasks that others use a brand new $600-$1000 PC for.  The reason they are able to accomplish this is offloading of load to the Comtrol products, as well as the fact they’ve chosen to use a Linux distribution aimed at just such a thing: to accomplish a task, and accomplish it well.  Not attempt to install a fully functioning desktop PC, but to accomplish a task.  Comtrol products, together with Linux, will allow you to do just such a thing, and with no PC budget to speak of – disregarding that old Pentium II you keep meaning to throw away.

For more information >> Comtrol’s DeviceMaster device servers, RocketPort multi-port serial cards and RocketLinx® industrial Ethernet switches

Linux Distribution Links Updates on new versions of distributions, etc.

Puppy Linux Older PC Linux Distribution

If you have any questions whatsoever regarding Linux support, please contact Nick Thompson with Technical Support at nick.thompson@comtrol.com or (763) 957.6138.

SERIES: Linux Support at Comtrol – Part II

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Linux Virtualization with Comtrol Products: Extending hardware to serve a wider purpose

Linux

Comtrol products work very well in a Linux virtual machine / Hypervisor environment. Below I will outline how some of our customers are extending the use of a DeviceMaster® or a RocketPort® uPCI / RocketPort® Infinity / RocketPort® Express by using a virtual machine solution called Xen.

– Nick Thompson

Xen PCI Pass Through and the advantages offered to our uPCI / PCIe offerings:

Xen is by far the most simple Linux virutualization solution regarding PCI Pass Through. PCI Pass Through comes in handy in that we are able to offer the PCI bus of the ‘Bare Metal’ Hypervisor  /  O/S install up to the Virtual Machines running on the Hypervisor. This allows us a lot of possibilities.

One of these possibilities, and one that we’ve had customers use before, is the ability to give 4 machine 4 serial ports each off of a 16 port card, or 8 machine 4 ports off of a 32 port card, etc. This, in the end, allows you a very large number of virtual machines; who all may be in need of a serial port or four (or more) to connect to whatever serial devices you may be using.

Xen working with the DeviceMaster: Simple, yet elegant:

Xen allows internal to the Hypervisor network traffic to communicate on virtual network interface cards inside of the Hypervisor itself. That traffic is then allowed to communicate into what is essentially a virtual switch which allows this traffic out to the real world network interface card, thus allowing traffic from a virtual machine with no physical network interface to communicate with a DeviceMaster which is on a switch connected to the physical, bare metal PC – and all with ease.

Effectively using all your resources: Xen and Comtrol

By making use of Xen, a company is able to stretch not only the use of one PC and its CPU power to make what are essentially multiple PCs – but also to stretch the number of ports on a DeviceMaster or RocketPort product out to multiple virtual machines. This is largely important as far as making full use of a company’s hardware, and I find that customers make good use of resources once a situation like this has been planned out and set up.

Xen in pictures: Understanding the basics of Virtualization with Xen:

Below you’ll see the Host Hardware (bare metal machine / PC) with its ram, hard drives and pieces of real hardware—its PCI bus and Network Interface Card, etc. These are ‘exported’ via the Hypervisor layer to the various virtual machines. (vm0, vm1, vmN, etc.) The control domain is there to handle the Virtual Machines themselves.

Xen Diagram

Xen and Comtrol hardware go well together, and can be leveraged to save money and make the best use of a companies hardware; to squeeze out extra performance enough from resources that are being unused to create Virtual Machines that wouldn’t have existed without this setup. This is a huge leap in cost effectiveness of hardware, and we will continue to see Virtualization shape the map of resource usage in the future. Comtrol will be here to help you manage your resources in the best manner possible.

If you have any questions whatsoever regarding Linux support, please contact Nick Thompson with Technical Support at nick.thompson@comtrol.com or (763) 957.6138.

SERIES: Linux Support at Comtrol – Part I

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We pride ourselves on supporting Linux with our products, and supporting it well here at Comtrol. Below, I will detail how things work out so well for us and our customers using Linux, and how we accomplish this.

– Nick Thompson

Kernel vs. Distro Support

We support the Linux *kernel,* and therefore all distributions, by providing a tarball (the source) to be compiled on any distribution you like.  We don’t just provide a ‘proprietary’ format like .rpm/.deb etc., which are meant for specific distributions.  This allows our hardware and drivers to be used on any Linux distribution out there.  This is a huge advantage to our customers.  Also, we support the *kernel,* not specific distributions, meaning support will be given for any distribution, not just the bigger, better known distributions.  This can and has come in handy for some niche distributions specific customers require for their operation.

Wide Range of Kernels Supported

We support a wide range of kernels with our Linux drivers here at Comtrol.  We have legacy 2.4.x support, and of course, support the 2.6.x kernel along with the newest bleeding edge 3.x.x Vanilla kernel and release candidates. Whether you’re running an old Red Hat Enterprise Linux 4.x with a 2.6.9 kernel, or the latest Gentoo with the 3.6.x Vanilla kernel release candidate, we can and will support you.

Day of Release Kernel Support

Comtrol provides driver functionality on the day of Vanilla kernel release, and most often -rcX (release candidate) functionality prior to Vanilla release.  This is helpful in early customer testing of systems with bleeding edge kernel requirements, and simply for testing of systems prior to final kernel release.  This is a big advantage in our niche market for customers, as we stick to it and have, for years now, had functionality on Day One of Vanilla kernel release (and most often beforehand with -rcX functionality). We get this functionality by painstakingly testing our drivers with every release candidate kernels (for example: 3.6.0-rc7) that is released, to identify problems early so they can be fixed before Vanilla release.  I am the gentleman who does the testing and verification of operation of the drivers each -rcX kernel/Vanilla kernels release and I am very pleased to be able to offer our customers such support.  We will continue to operate this way so as to provide the best Linux support we can to our customers.

Linux support series kernel information That Guy in the Penguin Suit

Here at Comtrol, you can rest assured knowing that I (to the left in the penguin suit) will always be happy to jump on the phone and do whatever needs to be done to get your Linux system operational with our products.

If you have any questions whatsoever regarding Linux support, please contact Nick Thompson with Technical Support at nick.thompson@comtrol.com or (763) 957.6138.


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