Category Archives: Software Engineering

How to create a virtual machine in VMware Workstation 15.5 Player

Host Operating system: openSUSE Leap 15.1

VMware Workstation Player is free for personal non-commercial use (business and non profit use is considered commercial use).

1. BIOS Settings

    • Example motherboard: Gigabyte AM4 with DualBIOS.
    • Main menu > MIT > Advanced CPU Core Settings > SVM Mode Enabled.
    • Main menu > Chipset > IOMMU Enabled.

DualBIOS means that the motherboard has both a ‘Main BIOS’ and a ‘Backup BIOS’, protecting users from BIOS failure due to virus, hardware malfunction or power failure during the update process. The motherboard has two chips. The M_BIOS (Main BIOS) and the B_BIOS (Backup BIOS).

MIT – Motherboard Intelligent Tweaker

SVM – Secure Virtual Machine

IOMMU – Input-Output Memory Management Unit.

2.  Create a Virtual Machine for Windows 10

VMware Workstation 15.5 Player is Type 2 hypervisor.

    • Open VMware Workstsation 15 Player.
    • Go to the Main menu > File > Create a New Virtual machine
    • Install operating system: you can select for example a Windows image (Win10_2004_EnglishInternational_x64.iso)
    • Virtual machine name: Windows 10 x64
    • Disk: Select the HDD or SDD. Enter the size e.g. 60 GB or larger
    • Hardware customization
      • Select the amount of memory in MB to be allocated to the virtual machine: 2 GB or more
      • Number of processor cores: 2
      • Display: Enable “Accelerate 3D graphics”



Oracle VM VirtualBox error message: Permission problem!

Operating system: openSUSE Leap 15.1

VirtualBox version: 6.0.18

Virtual box error message: You are not a member of the “vboxusers” group. Please add yourself to this group before starting VirtualBox. You could do it using: Yast / Security and Users / User and Group management. Don’t forget re-login your user account!


  • Open Yast Control Center
  • Open User and Group Management module (Category: Security and Users)
  • Select a User and then click Edit
  • Click the Details tab and select ‘vboxusers’
  • Click OK and logout
  • Login again

KeepPass error message: xdotool

Host operating system: openSUSE Leap 15.1

Application: KeePass ver.2.38

Error message: The ‘xdotool’ utility/package is required for auto-type.

What is xdotool? xdotool is a tool that lets you programatically (or manually) simulate keyboard input and mouse activity, move and resize windows, etc. It does this using X11’s XTEST extension and other Xlib functions.

Note: This message appears when you are trying to use the Auto-type function of KeePass.

Solution: Install xdotool (Fake keyboard/mouse input).

Combining strings in Python

Result: Boris Dimitrov

Hello World! in Python

First of all you need to install python if it is not already installed. Python download page:

Python installation path should be added as an system variable in Windows:

  • Open System Properties by typing sysdm.cpl in Command Prompt window
  • Go to the Advanced tab and click the Environment Variables
  • In System variables find the Path variable and click Edit
  • Add the path where Python is installed

In Windows you can open a command prompt and type the following command:

or just type py and press Enter. You must see Python start up:

If you are using Visual Studio Code do one of the following:

  • Right click anywhere in the editor window > Run Python file in Terminal
  • Main menu > View > Command Palette… > Python: Start REPL > Type the lines of code and press Enter
  • Select the Lines of code > right click > Run Selection/Line in Python Terminal

Mac mini (Late 2009) – Memory upgrade


  • Before: 2 GB 1067 MHz PC3-8500 DDR3 SO-DIMMs
  • After:
    • Capacity: 8 GB (2 X 4 GB)
    • Type: DDR3 SO-DIMMs Apple
    • Number of pins: 204
    • Voltage: 1.5 V
    • Frequency: 1066 MHz
    • Manufacturer: OWC (Other World Computing)
    • Model: OWC8566DDR3S8GP


Inkscape – RGBA

R – Red

G – Green

B – Blue

A – Alpha (transparency)

Example 1 (A = 255)

Draw a rectangle. Select the rectangle > Fill and Stroke… > select the Fill tab > choose Flat color > enter RGBA values.

Inkscape RGBA (1)

Example 2 (A = 150)

Inkscape RGBA (2)