Explanation

NVR (Network Video Recorder) is a device used to record video footage from IP (network) cameras.

It stores and manages surveillance video data digitally over a network.

Explanation

The ENIAC (Electronic Numerical Integrator and Computer), developed from 1943 to 1946.

It was the first general-purpose electronic digital computer.

It was designed for calculating artillery firing tables and utilized vacuum tubes.

Explanation

An Alternate key is any candidate key not chosen as the primary key.

It can still uniquely identify records, but isn't used as the main identifier.

Explanation

The Internal level in DBMS describes how data is physically stored in the database.

It is the closest level to the physical storage, dealing with file structures and indexes.

Explanation

There are 7 basic logic gates:

1. AND
2. OR
3. NOT
4. NAND
5. NOR
6. XOR
7. XNOR

These gates form the foundation of digital electronics and computing.