SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 _________ SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2(b) (Amendment No. ____) (1) Discovery Partners International, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 25467510 (CUSIP Number) December 31, 2000 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [_] Rule 13d-1(b) [_] Rule 13d-1(c) [X] Rule 13d-1(d) (1) The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 2 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Mayfield VIII, a California Limited Partnership - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. California - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,145,775 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,145,775 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,145,775 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.0% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. PN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 3 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Mayfield VIII Management, L.L.C. - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. Delaware - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,145,775 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,145,775 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,145,775 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.0% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. OO - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 4 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Mayfield Associates Fund II, a California Limited Partnership - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. California - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 112,928 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 112,928 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 112,928 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 0.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. PN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 5 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Yogen K. Dalal - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 6 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) F. Gibson Myers, Jr. - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 7 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Kevin A. Fong - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 8 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) William D. Unger - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 9 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Wendell G. Van Auken, III - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 10 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Michael J. Levinthal - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 11 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) A. Grant Heidrich, III - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,258,703 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,258,703 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,258,703 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.5% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 12 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Wende S. Hutton - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,145,775 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,145,775 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,145,775 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.0% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

- ------------------------- ---------------------- CUSIP NO. 25467510 13G Page 13 of 38 pages. - ------------------------- ---------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1. I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Entities Only) Russell C. Hirsch - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP 2. (a) [_] (b) [X] - ------------------------------------------------------------------------------ SEC USE ONLY 3. - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4. U.S. - ------------------------------------------------------------------------------ SOLE VOTING POWER 5. NUMBER OF -0- SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6. OWNED BY 2,145,775 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7. REPORTING -0- PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8. 2,145,775 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9. 2,145,775 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10. [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11. 9.0% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON 12. IN - ------------------------------------------------------------------------------

Item 1. (a) Name of Issuer: Discovery Partners International, Inc. (b) Address of Issuer's Principal Executive Offices: 9640 Towne Centre Drive San Diego, CA 92121 Item 2. (a) Name of Persons Filing: Mayfield VIII, a California Limited Partnership Mayfield VIII Management, L.L.C. Mayfield Associates Fund II, a California Limited Partnership Yogen K. Dalal F. Gibson Myers, Jr. Kevin A. Fong William D. Unger Wendell G. Van Auken, III Michael J. Levinthal A. Grant Heidrich, III Wende S. Hutton Russell C. Hirsch (b) Address of Principal Business Office: c/o Mayfield Fund 2800 Sand Hill Road Menlo Park, CA 94025 (c) Citizenship: Mayfield VIII and Mayfield Associates Fund II are California Limited Partnerships. Mayfield VIII Management is a Delaware Limited Liability Company. The individuals listed in Item 2(a) are U.S. citizens. (d) Title of Class of Securities: Common Stock, $0.001 par value (e) CUSIP Number: 25467510 Page 14 of 38 pages.

Item 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), check whether the person filing is a: Not applicable Item 4. Ownership. The information regarding ownership as set forth in Items 5-9 of Pages 2-13 hereto, is hereby incorporated by reference. For a summary of total ownership by all Reporting Persons, see Exhibit 3 hereto. Item 5. Ownership of Five Percent or Less of a Class. If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [ ]. Item 6. Ownership of More than Five Percent on Behalf of Another Person. Not applicable. Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person. Not applicable. Item 8. Identification and Classification of Members of the Group. Not applicable. Item 9. Notice of Dissolution of Group. Not applicable. Item 10. Certification. Not applicable. Page 15 of 38 pages.

SIGNATURES After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: February 13, 2001 MAYFIELD VIII A California Limited Partnership By: Mayfield VIII Management, L.L.C. Its General Partner By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory MAYFIELD VIII MANAGEMENT, L.L.C. By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory MAYFIELD ASSOCIATES FUND II A California Limited Partnership By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory YOGEN K. DALAL By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact F. GIBSON MYERS, JR. By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact KEVIN A. FONG By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact WILLIAM D. UNGER By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact WENDELL G. VAN AUKEN, III By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact Page 16 of 38 pages.

MICHAEL J. LEVINTHAL By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact A. GRANT HEIDRICH, III By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact WENDE S. HUTTON By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact RUSSELL C. HIRSCH By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact Page 17 of 38 pages.

EXHIBIT INDEX Exhibit 1 - Joint Filing Agreement Exhibit 2 - Powers of Attorney Exhibit 3 - Ownership Summary Page 18 of 38 pages.

EXHIBIT 1 JOINT FILING AGREEMENT ---------------------- Pursuant to Rule 13d-1(k)(1)(iii), we the undersigned agree that the Schedule 13G, to which this Joint Filing Agreement is attached as Exhibit 1, is filed on behalf of each of us. Date: February 13, 2001 MAYFIELD VIII A California Limited Partnership By: Mayfield VIII Management, L.L.C. Its General Partner By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory MAYFIELD VIII MANAGEMENT, L.L.C. By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory MAYFIELD ASSOCIATES FUND II A California Limited Partnership By: /s/ James T. Beck -------------------------------------- James T. Beck, Authorized Signatory YOGEN K. DALAL By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact F. GIBSON MYERS, JR. By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact KEVIN A. FONG By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact WILLIAM D. UNGER By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact Page 19 of 38 pages.

WENDELL G. VAN AUKEN, III By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact MICHAEL J. LEVINTHAL By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact A. GRANT HEIDRICH, III By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact WENDE S. HUTTON By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact RUSSELL C. HIRSCH By: /s/ James T. Beck -------------------------------------- James T. Beck, Attorney In Fact Page 20 of 38 pages.

EXHIBIT 2 --------- RESOLUTION OF SIGNATURE AUTHORITY FOR JAMES T. BECK This Resolution is formed and entered into as of the 1/st/ day of May, 2000, by and among James T. Beck ("Beck"), Mayfield Associates Fund, a California limited partnership ("Associates"), Mayfield Associates Fund II, a California limited partnership ("Associates II"), Mayfield Associates Fund III, a California limited partnership ("Associates III"), Mayfield Associates Fund IV, a Delaware limited partnership ("Associates IV"), Mayfield Associates Fund V, a Delaware limited partnership ("Associates V"), Mayfield Associates Fund VI, a Delaware limited partnership ("Associates VI"), Mayfield III, a California limited partnership ("Mayfield III"), Mayfield IV, a California limited partnership ("Mayfield IV"), Mayfield V, a California limited partnership ("Mayfield V"), Mayfield VI Investment Partners, a California limited partnership ("Mayfield VI"), Mayfield VII, a California limited partnership ("Mayfield VII"), Mayfield VIII, a California limited partnership ("Mayfield VIII"), Mayfield IX, a Delaware limited partnership ("Mayfield IX"), Mayfield X, a Delaware limited partnership ("Mayfield X"), Mayfield XI, a Delaware limited partnership ("Mayfield XI"), Mayfield XI Qualified, a Delaware limited partnership ("Mayfield XI Qualified"), Mayfield Software Partners, a California partnership ("Mayfield Software Partners"), Mayfield Software Technology Partners, a California partnership ("Mayfield Software Technology Partners"), Mayfield Medical Partners, a California partnership ("Mayfield Medical Partners"), Mayfield Medical Partners 1992, a California partnership ("Mayfield Medical Partners 1992"), Mayfield V Management Partners, a California limited partnership ("Mayfield V Management"), Mayfield VI Management Partners, a California limited partnership ("Mayfield VI Management"), Mayfield VII Management Partners, a California limited partnership ("Mayfield VII Management"), Mayfield VIII Management, L.L.C., a Delaware limited liability company ("Mayfield VIII Management"), Mayfield IX Management, L.L.C., a Delaware limited liability company ("Mayfield IX Management"), Mayfield X Management, L.L.C., a Delaware limited liability company ("Mayfield X Management"), Mayfield XI Management, L.L.C., a Delaware limited liability company ("Mayfield XI Management"), Mayfield Principals Fund, L.L.C., a Delaware limited liability company ("Mayfield Principals Fund"), Mayfield Principals Fund II, L.L.C., a Delaware limited liability company ("Mayfield Principals Fund II"), MF Partners, a California partnership ("MF Partners"), Mayfield Partners, a California partnership ("Mayfield Partners"), Mayfield '94 Partners, a California limited partnership ("Mayfield '94 Partners"), Mayfield '96 Partners, a California limited partnership ("Mayfield '96 Partners'), Valley Partners I, a California partnership ("Valley Partners I"), Valley Partners II, a California partnership ("Valley Partners II"), Valley Partners III, a California partnership ("Valley Partners III"), and MUHL Partners, a California partnership ("MUHL Partners") (with Associates, Associates II, Associates III, Associates IV, Associates V, Associates VI, Mayfield III, Mayfield IV, Mayfield V, Mayfield VI, Mayfield VII, Mayfield VIII, Mayfield IX, Mayfield X, Mayfield XI, Mayfield XI Qualified, Mayfield Software Partners, Mayfield Software Technology Partners, Mayfield Medical Partners, Mayfield Medical Partners 1992, Mayfield V Management, Mayfield VI Management, Mayfield VII Management, Mayfield VIII Management, Mayfield IX Management, Mayfield X Management, Mayfield XI Management, Mayfield Principals Fund, Mayfield Principals Fund II, Page 21 of 38 pages.

MF Partners, Mayfield Partners, Mayfield '94 Partners, Mayfield '96 Partners, Valley Partners I, Valley Partners II, Valley Partners III, and MUHL Partners being hereinafter collectively referred to as the "Mayfield Entities"), and Mayfield Fund, L.L.C., a Delaware limited liability company (the "Company"), the service company with respect to the Mayfield Entities. WITNESSETH WHEREAS: The Company and the General Partners of the Mayfield Entities desire - ------- to empower the Controller of the Company, Beck, to take certain actions and to execute certain documents on behalf of the Company and the Mayfield Entities; RESOLVED: Beck is authorized and empowered to open and maintain bank accounts, - -------- to deposit or withdrawal funds, to execute checks, and to take to any actions and execute any appropriate documents in connection therewith on behalf of the Company and the Mayfield Entities; RESOLVED FURTHER: That Beck is authorized and empowered to take all other - ---------------- actions and execute all other documents necessary or appropriate to the day-to- day management of the Company and the Mayfield Entities, and to appoint Beck signing singly, as true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned, forms (including any amendments or supplements) relating to transactions in securities in which the undersigned may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. Page 22 of 38 pages.

IN WITNESS WHEREOF, the parties hereto have caused this Resolution to be executed as of the date first above written. /s/ James T. Beck - ---------------------------------------- James T. Beck MAYFIELD FUND, L.L.C. A DELAWARE LIMITED LIABILITY COMPANY By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD ASSOCIATES FUND, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ A. Grant Heidrich, III ------------------------------------- General Partner MAYFIELD ASSOCIATES FUND II, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ A. Grant Heidrich, III ------------------------------------- General Partner MAYFIELD XI QUALIFIED, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD XI MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD SOFTWARE PARTNERS, A CALIFORNIA PARTNERSHIP By: MAYFIELD VI INVESTMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: MAYFIELD VI MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP General Partner of Mayfield VI Investment Partners By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD SOFTWARE TECHNOLOGY PARTNERS, Page 23 of 38 pages.

A CALIFORNIA PARTNERSHIP By: MAYFIELD VI INVESTMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: MAYFIELD VI MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP General Partner of Mayfield VI Investment Partners By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD MEDICAL PARTNERS, A CALIFORNIA PARTNERSHIP By: MAYFIELD VI INVESTMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: MAYFIELD VI MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP General Partner of Mayfield VI Investment Partners By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD MEDICAL PARTNERS 1992, A CALIFORNIA PARTNERSHIP By: MAYFIELD VII, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: MAYFIELD VII MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP General Partner of Mayfield VII By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD V MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD VI MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner Page 24 of 38 pages.

MAYFIELD VII MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD VIII MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD IX MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD X MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD PRINCIPALS FUND, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY By: MAYFIELD X MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD PRINCIPALS FUND II, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY By: MAYFIELD XI MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD PARTNERS, A CALIFORNIA PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner Page 25 of 38 pages.

MAYFIELD '94 PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD '96 PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MF PARTNERS, A CALIFORNIA PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MUHL PARTNERS, A CALIFORNIA PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner VALLEY PARTNERS, A CALIFORNIA PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner VALLEY PARTNERS II, A CALIFORNIA PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner VALLEY PARTNERS III, A CALIFORNIA PARTNERSHIP By: /s/ Yogen K. Dalal ------------------------------------- General Partner MAYFIELD ASSOCIATES FUND III, A CALIFORNIA LIMITED PARTNERSHIP By: MAYFIELD VIII MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD ASSOCIATES FUND IV, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD IX MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member Page 26 of 38 pages.

MAYFIELD ASSOCIATES FUND V, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD X MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD ASSOCIATES FUND VI, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD XI MANAGEMENT, L.L.C., A DELAWARE LIMITED COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD III, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD IV, A CALIFORNIA LIMITED PARTNERSHIP By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD V, A CALIFORNIA LIMITED PARTNERSHIP By: MAYFIELD V MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD VI INVESTMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP By: MAYFIELD VI MANAGEMENT PARTNERS, A CALIFORNIA LIMITED COMPANY Its General Partner By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner MAYFIELD VII, A CALIFORNIA LIMITED PARTNERSHIP By: MAYFIELD VII MANAGEMENT PARTNERS, A CALIFORNIA LIMITED PARTNERSHIP Its General Partner By: /s/ F. Gibson Myers, Jr. ------------------------------------- General Partner Page 27 of 38 pages.

MAYFIELD VIII, A CALIFORNIA LIMITED PARTNERSHIP By: MAYFIELD VIII MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD IX, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD IX MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD X, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD X MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member MAYFIELD XI, A DELAWARE LIMITED PARTNERSHIP By: MAYFIELD XI MANAGEMENT, L.L.C., A DELAWARE LIMITED LIABILITY COMPANY Its General Partner By: /s/ Yogen K. Dalal ------------------------------------- Managing Member Page 28 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Yogen K. Dalal ----------------------------------- Yogen K. Dalal Page 29 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Frank G. Myers, Jr. -------------------------------------- Frank G. Myers, Jr. Page 30 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Kevin A. Fong ------------------------------------- Kevin A. Fong Page 31 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ William D. Unger -------------------------------------- William D. Unger Page 32 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Wendell G. Van Auken III --------------------------------------- Wendell G. Van Auken III Page 33 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Michael J. Levinthal ---------------------------------------- Michael J. Levinthal Page 34 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ A. Grant Heidrich III --------------------------------------- A. Grant Heidrich III Page 35 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22/nd/ day of May 2000. /s/ Wende S. Hutton -------------------------------------- Wende S. Hutton Page 36 of 38 pages.

POWER OF ATTORNEY For Executing Securities and Exchange Commission Filings Known all by these present, that the undersigned hereby constitutes and appoints James T. Beck signing singly, his or her true and lawful attorney-in-fact to: 1. Execute for and on behalf of the undersigned (both in the undersigned's individual capacity and as a member of any limited liability company, a partner of any limited or general partnership, an officer, director or stockholder of any corporation or otherwise as an authorized signatory of any entity for which the undersigned is authorized to sign) forms (including any amendments or supplements) relating to transactions in securities in which the undersigned, individually or by entities controlled by Mayfield Fund and its affiliates, may have a reporting obligation, in accordance with Section 16(a) or Section 13 of the Securities Exchange Act of 1934 and the rules thereunder and in connection with any applications for EDGAR access codes; 2. Do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such forms and the filing of such forms with the United States Securities and Exchange Commission and any other authority; 3. Take any other action on connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion. The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, hereby ratifying and confirming all that such attorney-in-fact shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming any of the undersigned's responsibilities to comply with Section 16(a) or Section 13 of the Securities Exchange Act of 1934. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as this 22nd day of May 2000. /s/ Russell C. Hirsch --------------------------------------- Russell C. Hirsch Page 37 of 38 pages.

EXHIBIT 3 Number of Number of Percent of Class Name of Reporting Person Shares Shares Beneficially (Direct) (Indirect) Owned (1) - -------------------------------------------------------------------------------- ---------------- Mayfield VIII, 2,145,775 (2) -0- 9.0% a California Limited Partnership Mayfield VIII Management, L.L.C. -0- 2,145,775 (2) 9.0% Mayfield Associates Fund II, a 112,928 (3) -0- 0.5% California Limited Partnership Yogen K. Dalal -0- 2,258,703 (4) 9.5% F. Gibson Myers -0- 2,258,703 (4) 9.5% Kevin A. Fong -0- 2,258,703 (4) 9.5% William D. Unger -0- 2,258,703 (4) 9.5% Wendell G. Van Auken, III -0- 2,258,703 (4) 9.5% Michael J. Levinthal -0- 2,258,703 (4) 9.5% A. Grant Heidrich, III -0- 2,258,703 (4) 9.5% Wende S. Hutton -0- 2,145,775 (4) 9.0% Russell C. Hirsch -0- 2,145,775 (4) 9.0% Total 2,258,703 9.5% (1) The respective percentages set forth in this column were obtained by dividing the number of shares by the aggregate number of outstanding shares of Common Stock as of October 31, 2000 as reported in the Issuer's Form 10-Q for the quarter ended September 30, 2000. (2) Represents 2,145,775 shares held directly by Mayfield VIII, of which Mayfield VIII Management is the sole General Partner. (3) Represents 112,928 shares held directly by Mayfield Associates Fund II. (4) Includes shares held directly by Mayfield VIII and Mayfield Associates Fund II. The individual Reporting Persons are Members of Mayfield VIII Management, which is the General Partner of Mayfield VIII. The individual Reporting Persons may be deemed to have shared voting and dispositive power over the shares which are or may be deemed to be beneficially owned by Mayfield VIII, but disclaim such beneficial ownership. The individual Reporting Persons, other than Ms. Hutton and Mr. Hirsch, are also General Partners of Mayfield Associates Fund II. Ms. Hutton and Mr. Hirsch are limited partners of Mayfield Associates Fund II. The individual Reporting Persons, other than Ms. Hutton and Mr. Hirsch, may be deemed to have shared voting and dispositive power over the shares which are or may be deemed to be beneficially owned by Mayfield Associates Fund II, but disclaim such beneficial ownership. Page 38 of 38 pages.