- Testing: The process of executing a system with the intent of finding defects including test planning prior to the execution of the test cases.
- Quality Control: A set of activities designed to evaluate a developed working product.
- Quality Assurance: A set of activities designed to ensure that the development and/or maintenance process is adequate to ensure a system will meet its objectives.
The key difference to remember is that QA is interested in the process whereas testing and quality control are interested in the product. Having a testing component in your development process demonstrates a higher degree of quality (as in QA).
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Development environment: Typically the developer team will set up a local environment on their machines to develop. Code developed by multiple developers will typically be maintained and synched under some version control system.
Test environment: Code developed by the developer team is combined together and built. These binaries are typically deployed on a test server/s. The QA team will use this as their test environment and run all kinds of test cases in such an environment and identify bugs
Production environment: Bugs are identified, fixed, redeployed on the test environment and the cycle continues. Once a stable build has been achieved, it is rolled off for actual use, which would be a production server.
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Parallel ports are easy to program and faster compared to the serial ports. But main disadvantage is it needs more number of transmission lines. Because of this reason parallel ports are not used in long distance communications. Let us know the basic difference between working of parallel port and serial port.
In serial ports, there will be two data lines: One transmission and one receive line. To send a data in serial port, it has to be sent one bit after another with some extra bits like start bit, stop bit and parity bit to detect errors.
In parallel port, all the 8 bits of a byte will be sent to the port at a time and a indication will be sent in another line. There will be some data lines, some control and some handshaking lines in parallel port. If three bytes of data 01000101 10011100 10110011 is to be sent to the port, parallel port communication is faster then serial port.

