Under Perens' definition, open source describes a broad general type of software license that makes source code available to the general public with relaxed or non-existent copyright restrictions.
1 Illnesses such as the flu or colds. Home treatment of your flu and cold symptoms usually will relieve lightheadedness. 2  Vomiting, diarrhea, fevers, and other illnesses that cause dehydration.  Very deep or rapid breathing (hyperventilation).
If you sit up or stand up too quickly, your blood pressure may drop and you may feel faint. Another common cause of lightheadedness is when the blood flow from the heart is not sufficient. There are certain conditions of the heart that may be responsible for this.