MICROWARE SYSTEMS CORPORATION
                           1500 Northwest 118th Street
                             Des Moines, Iowa 50325
                                 (515) 223-8000


                                  July 6, 2001


Dear Shareholders:

     I am pleased to inform you that Microware Systems Corporation (the
"Company") has entered into an Agreement and Plan of Merger dated as of June 29,
2001 (the "Merger Agreement") with RadiSys Corporation, an Oregon corporation
("RadiSys"), and Drake Merger Sub, Inc., an Iowa corporation and a wholly-owned
subsidiary of RadiSys ("Purchaser"), pursuant to which Purchaser has today
commenced a cash tender offer (the "Offer") to purchase all of the outstanding
shares ("Shares") of common stock, no par value per share ("Common Stock"), of
the Company at a purchase price of $0.68 per Share, net to the seller in cash.
The Merger Agreement provides for the making of the Offer which, if consummated
and certain conditions are satisfied, will be followed by a merger (the
"Merger") with the Company surviving as a wholly-owned subsidiary of RadiSys. In
the Merger, Shares will be converted into the right to receive an amount in cash
equal to the price per Share paid pursuant to the Offer, without interest
thereon. YOUR BOARD OF DIRECTORS HAS UNANIMOUSLY APPROVED THE MERGER AGREEMENT
AND THE OFFER AND RECOMMENDS THAT HOLDERS OF SHARES ACCEPT THE OFFER AND TENDER
THEIR SHARES PURSUANT TO THE OFFER.

     In arriving at its recommendation, the Directors of your Company each gave
consideration to the factors described in the attached Schedule 14D-9 that is
being filed today with the Securities and Exchange Commission, including, among
other things, the opinion of Houlihan Lokey Howard & Zukin Capital, the
Company's financial advisors, that, subject to the various assumptions and
limitations set forth therein, the $0.68 cash price to be received by the
holders of Shares in the Offer and the Merger pursuant to the Merger Agreement
is fair to such holders from a financial point of view.

                                      Very truly yours,


                                      /s/ Kenneth B. Kaplan
                                      Kenneth B. Kaplan
                                      Chairman of the Board and Chief Executive
                                        Officer