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TCAD station, part I

You certainly know the old tune on the lack of “professional” software for Linux, with “professional“ being usually an implicit synonym for Microsoft Office and the Adobe Creative Suite. For a scientist or engineer, people joining this chorus appear to be misinformed and to be motivated by ideology rather than reality. In technically oriented fields, software is in fact mostly cross-platform or even developed primarily for Linux. That's true in particular for multithreaded software with non-negligible demands in terms of computational resources and five- to six-figures price tags. Examples include Maxwell solvers, multiphysics solutions, and TCAD packages.

Commercial software for Linux is usually certified only for one of the enterprise Linux distributions, namely, Redhat and SUSE Enterprise Linux (RHEL and SLES). Some of this products turn out to be actually distribution-agnostic, meaning that they run without any problems also on, e.g., Debian. But in many other cases, the software only runs and even only installs on systems with the distribution it was developed for. I've learned that the hard way, wasting an entire day trying to get the commercial finite-difference time-domain simulation package FDTD solutions to work under Debian Stretch. In the end, we've used Meep instead.

I've vowed that this wouldn't happen again, and since we are in the process to evaluate some selected TCAD solutions (all of which are certified for RHEL only), it seemed to be wise to set up a test server running CentOS (a binary-compatible clone of RHEL). The TCAD software requires a graphical interface, but I did not intend to perform a standard installation, which results in a complete Gnome desktop suitable for a workstation rather than a compute server. For servers, I prefer the installation to be as lightweight as possible. For example, I usually install the tiling window manager wmii if a graphical interface is required or desirable on a server.

Since I'm not at all familiar with CentOS and the available software, I decided to first set up a virtual machine to look for possible pitfalls. For the base instalIation, I've downloaded and installed the minimal ISO which I've then, upon first boot, updated with:

yum update
grub2-mkconfig -o /boot/grub2/grub.cfg

Why the reconfiguration of grub? Well, the update installed a new kernel, but CentOS did not automatically update the grub configuration file. Weird, but true.

CentOS offers three tiling window manager, two of which I'm familiar with: i3 and xmonad (never even heard about spectrwm). On second thought, however, I realized that it may be a better idea to install a more conventional desktop to give the TCAD testers an environment they feel comfortable with. XFCE seemed to be a reasonable compromise and can be installed with these few steps:

yum install epel-release -y
yum groupinstall "X Window System" -y
yum groupinstall "Xfce" -y
systemctl get-default
systemctl set-default
systemctl isolate

The last step seamlessly starts the X Window system and thus catapults one into the graphical desktop. Slick! Now we only want a resolution higher than the oldfashioned 1024x768 offered by the default (VESA) driver. In other words, we need to install the Virtualbox guest additions:

yum install dkms
yum groupinstall "Development Tools"

To install the guest additions, I first inserted the 'Guest Additions CD Image' in the 'Devices' menu and then downloaded the image. After the download, I mounted the image and compiled the guest additions:

mkdir /media/vboxadditions
mount /dev/cdrom /media/vboxadditions
cd `/media/vboxadditions <file:///home/cobra/Documents/media/vboxadditions>`_

Still no higher display resolutions available? The script in this thread enabled me to activate the 'Auto-resize Guest Display' option in the 'View' menu, which finally allowed me to use the desired full HD resolution (on a WQHD monitor):

Diplay_Name=`xrandr | grep connected | cut -d' ' -f1`
Display_Spec=`cvt 1920 1080 | grep Modeline | cut -d' ' -f2 |cut -d '"' -f2`
Display_Params=`cvt 1920 1080 | grep Modeline | cut -d' ' -f2-18 | sed s/'"'//g`

xrandr --newmode $Display_Params
xrandr --addmode $Diplay_Name $Display_Spec
xrandr --output $Diplay_Name --mode $Display_Spec

In the second part of this post, I will write about the installation of CentOS on the physical server we have reserved for the evaluation stage. From the (largely) pleasant experience with the virtual machine, I expected this task to be entirely straightforward. I thought to be done in an hour, including configuration of user accounts as well as the sshd and vncd daemons for remote access. Well ... it took more than one day. Stay tuned. ;)

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