This excerpt taken from the HPQ 10-Q filed Jun 8, 2007.
B. Period of Option. The Committee may specify, at the time of grant a vesting schedule for any option. If no vesting schedule is specified, no option may be exercised before the first anniversary of the date upon which it was granted, nor may it be exercised as to more than one-fourth of the number of shares covered thereby before the second anniversary of such date, nor as to more than one-half of the number of shares covered thereby before the third anniversary of such date, nor as to more than three-fourths of the number of shares covered thereby before the fourth anniversary of such date. Any option granted pursuant to the Plan shall become exercisable in full upon the retirement of the optionee because of age or total and permanent disability or upon the death of the optionee. Except as provided in this subsection B, no option shall be exercisable after the expiration of 10 years from the date upon which such option is granted. However, the Committee may, at the time an option is granted to any employee who is not subject to Section 16 of the Exchange Act, specify a different term for the option up to a maximum term of 10.5 years. Each option shall be subject to termination before its date of expiration as hereinafter provided.