You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who did microsoft strike a deal with to provide dos operating system?" whose answer is IBM.
Each document should contain about 30 words, and these documents should contain useful information.

Query: Microsoft DOS deal partner
Useful Output:

Doc 1: For Microsoft, the agreement elevates it from a mere supplier to I.B.M., with the risk that it could one day be cut off, into more of a partner.
Doc 2: In partnership with IBM, Microsoft is releasing the source code to MS-DOS 4.00 under the MIT license. Learn more.
Doc 3: Microsoft's agreement with IBM prohibited IBM from licensing DOS, but placed no restrictions on Microsoft, Rochelle Ruffer and Don Waldman note
Doc 4: In November 1980, Bill Gates, Paul Allen and Bob O'Rear inked a legendary contract with IBM. That non-exclusive agreement led to Bob writing MS-DOS with Tim
Doc 5: When Microsoft signed the contract with IBM in November 1980, they had no such operating system. They too outsourced it, by first licensing then