Dear Member:

The 1998 Annual Meeting of Members of Petrotechnical Open Software Corporation (the "Company") will be held at Luxury Collection Hotel, 1919 Briar Oaks Lane, Houston, Texas on Tuesday, October 20, 1998 at 9:00 a.m., local time, to consider and act upon the following matters:

1. To ratify the Amended and Restated Bylaws of the Corporation.
2. To elect two (2) Directors of the Corporation from the Oil Company Industry Sector.
3. To elect one (1) Director of the Company from the Commercial Industry Sector.
4. To elect one (1) Director of the Company from the Non-profit Industry Sector.
5. To transact such other business as may properly come before the meeting or any adjournment thereof.

Members of record at the close of business on September 20, 1998 are entitled to notice of, and to vote at, the Annual Meeting.

All Members are cordially invited to attend the meeting.

Houston, Texas
September 18, 1998

WHETHER OR NOT YOU EXPECT TO ATTEND THE MEETING, PLEASE COMPLETE, DATE AND SIGN THE ENCLOSED PROXY BALLOT AND PROMPTLY MAIL IT TO POSC AT THE ADDRESS ABOVE TO ASSURE REPRESENTATION AT THE MEETING.