1. Project background - status quo in practice
1.1. Status quo
1.2. Technical debts arise
1.3. Knowledge becomes person dependent
2. On the way to the solution
2.1. Text-based solution
2.2. YouTube
3. Virtual Reality - the solution
3.1. The solution
3.2. Hardware used
4. Benefits of the solution
4.1. Users
4.2. Always up-to-date
4.3. Inhibition threshold to use virtual reality

1. Project background - status quo in practice

1.2. Technical debts arise

The business organization is constantly challenged. New markets are to be opened or the customer is to be integrated into the process chain. For example, if the customer is to receive a notification on his smartphone as soon as the goods leave the warehouse and are on their way to him. A requirement that was not foreseeable 30 years ago. All this happens under increasing time pressure for all parties concerned. Software development departments rarely have time to document immediately why an enhancement requirement was implemented in a certain way. Later it will not be done anymore – for lack of time. This results in so-called technical debts. Technical debts have a direct impact and prolong the duration and associated costs of extending or adapting the software. Increasing implementation times and costs are the interest that must be paid for technical debts. Older buildings are brought up to the current state of the art by a building renovation. In software engineering there is a counterpart to building renovation: code refactoring. This means that the source code will be fundamentally revised so that future extensions of the system can be carried out quickly and securely. In practice, code refactoring is only carried out in the rarest of cases due to time constraints. As a result, knowledge about the dependencies and connections in the software system becomes strongly person dependent.

1.3. Knowledge becomes person dependent

The knowledge about dependencies and connections in the software system - the big picture - is present in the minds of a few developers. When these developers leave the company or retire, this know-how is also permanently lost. New employees who take over a long-standing software system for support are thus faced with two challenges:

• On the one hand: learning legacy technology, such as Cobol - this is the simpler part.
• On the other hand: they must come to the Big Picture from the existing extensive and complex source code - this is the tedious and time-consuming part.
This problem is an immense one in practice. It is almost impossible for companies to find new talent for legacy systems.

2. On the way to the solution

In order to support the situation described above, we have considered:

2.1. Text-based solution

Complex software systems are comparable to a ball of wool with threads of different colours. You cannot dissolve the ball of wool by pulling out one end of the thread and all the colours dissolve. Every text-based solution, a report, just as an example, that is supposed to describe the big picture of a complex software system, inevitably results in an extensive text. The reader must spend a lot of time studying in order to understand the results correctly. Time taken up by employees who already have no time. Moreover, text-based solutions become obsolete very quickly if they are not updated manually. Thus, they become useless very quickly. These solutions are ruled out.

2.2. YouTube

YouTube is a wonderful medium. Many don't read a line of a user manual to explore new software or a new game. Instead, many of us search YouTube for a video to visually follow the behavior of the software and learn how to use it. YouTube is an excellent medium - but for instructional videos. In the described issue of legacy software, it is necessary that the user (e.g. a project manager, business analyst or software engineer) can participate interactively. Also, YouTube cannot help with the described issue.

3. Virtual Reality - the Solution

3.1. The Solution

The quote comes from Einstein: "Problems can never be solved with the same way of thinking that caused them". We found a solution for accessing the big picture and analysing legacy systems: Virtual reality. Virtual Reality is the representation and perception of reality in a computer-generated interactive environment. In games, for example, players build worlds and characters and interact with this world. From the source code of a Cobol legacy system (mostly hundreds of single programs) we automatically build a legacy universe in Virtual Reality, which can be interactively analysed. The legacy universe includes all programs and databases of the system with all its dependencies. In addition, core parameters such as size, complexity, detected anomalies or existing technical debts can be displayed for each program and database used. Navigation in the legacy universe is performed by a controller. With the controller, the individual objects can be directly controlled and zoomed in on. But you can also use the menu control and a table to search / sort with all programs and select elements of special interest in order to see all dependencies with the incoming and outgoing information flows in the virtual space. The time required to analyse legacy systems is reduced to a fraction of the time required for conventional manual analysis. What's more, virtual reality makes it possible to perceive the complexity of a system to its full extent - in a way that is not possible with any report. The analysis can be performed either individually or as a group in virtual reality.

3.2. 3.2. Hardware used

The operational departments entrusted with the creation and further development of legacy systems have no experience with virtual reality. Therefore one requirement was that the necessary VR hardware must be very easy to operate - this applies to both the VR glasses and the controller. Our choice fell on the VR glasses Oculus GO.

4. Benefits of the solution

4.1. Users

The solution is intended for the circle of users, who must get a holistic picture of a legacy system that has grown over decades. For example, this applies to project managers, software engineers or business analysts. This group of people is particularly claimed when the effort, time required and risks involved in a legacy project have to be assessed. The benefit of the application lies in the fact that the big picture of a legacy system does not have to be laboriously compiled manually from the source code, but is automatically collected and displayed in virtual reality. Virtual reality enables a completely new and intensive perception of the size and complexity of a legacy system and its parts.

4.2. Always up-to-date

Due to the automated creation and updating of the VR model via WIFI, the VR model cannot become obsolete like reports. Theoretically, the VR model could be updated daily. In practice, updating the VR model after code rebuild work will make sense if structural changes have been made, for example if programs are added or removed or if new external systems have been connected.

4.3. Inhibition threshold to use virtual reality

As mentioned, the application of Virtual Reality in legacy software development is a completely new way of accessing the structure of a software system. So far, we have not noticed any aversion or shyness to VR glasses, not even among older users.