Petitioner sought a writ of mandate contending he was eligible for Proposition 36 sentencing, because although he had a conviction within the five-year “washout” period, the conviction was for an offense which occurred in 1997, which was outside the washout period. The appellate court here agreed and issued the writ of mandate. The washout period commenced when petitioner committed the disqualifying prior felony, as opposed to when he was convicted of that felony. The language of Penal Code section 1210.1, subdivision (b)(1) is clear and unambiguous.