What is the burden of proving ineffective assistance to the effectiveness of the trial counsel?

^3. Appellant's challenges can be construed to be a challenge to the effectiveness of his trial counsel. The defendant has the burden of proving ineffective assistance of trial counsel. To prevail on a claim of ineffective assistance of trial counsel, the defendant must establish not only deficient performance, which is performance below an objective standard of reasonableness, but also prejudice. A court must indulge a strong presumption that counsel's conduct falls within the wide range of reasonable professional assistance. Tactical errors are generally not deemed reversible. Counsel's decisionmaking is evaluated in the context of the available facts. To the extent the record fails to disclose why counsel acted or failed to act in the manner challenged, appellate courts will affirm the judgment unless counsel was asked for an explanation and failed to provide one, or, unless there simply could be no satisfactory explanation. Prejudice must be affirmatively proved. The record must affirmatively demonstrate a reasonable probability that, but for counsel's unprofessional errors, the result of the proceeding would have been different. (People v. Maury (2003) 30 Cal.4th 342, 389.) Attorneys are not expected to engage in tactics or to file motions that are futile. (Id. at p. 390; also see People v. Mendoza (2000) 24 Cal.4th 130, 166.)