MS-DOS resulted from a request in 1981 by IBM for an operating system to use in its IBM PC range of personal computers. Microsoft quickly bought the rights to 86-DOS from Seattle Computer Products, and began work on modifying it to meet IBM's specification.
Complications from whooping cough can include weight loss, loss of bladder control, fainting, rib fractures from severe coughing, and pneumonia. A small percentage of adolescents and adults with whooping cough need to be hospitalized for their illness. In one study, 61% of adults with whooping cough missed work.
The course of whooping cough is divided into three stages. The first stage of whooping cough is the catarrhal (runny nose) stage. This phase typically lasts for one to two weeks. Symptoms during this phase resemble that of an upper respiratory illness: runny nose, nasal congestion, sneezing, and occasional cough. A low-grade fever may be present in some cases.