Hardware is the single system starting point. The operating system is the next layer on top of the hardware, Linux and macOS.
- Hacking and on the other side Security and Cryptography.
Data
In any business being adept at using Excel is a critical skill and the first step to dealing with data. As you move away from single table data sources you bring in Databases and Analytics. As your data needs become more complex Data Engineering becomes an essential skill set within the org.
Software Development
Algorithms
Open Source book on Algorithms by Jeff Erickson
Infrastructure
This System Design UI Tool is useful for mapping out infrastructure. Testing distributed systems Home Networking