The following article is written in general. Nothing to do with Holidex.
Observations in Legacy systems and Present Systems:
1. Excellent documentation for Booking Agents, Users ..etc
2. 99.999 up time.
3. Capable to take more load
1. Lack of documentation for developers.
2. Mixed business rules across different layers
3. In modern cloud computing, difficult to achieve 99.999 up time.
4. Difficult to deploy across continents.
5. Failed to maintain knowledge and Failed to retain staff who worked long time on systems.
6. Not cost effective