Complex sentence: All ATS/360 input/output operations utilized EXCP exclusively, and task switching was accomplished asynchronously as an extension of ATS/360's EXCP appendages and synchronously as an extension of ATS/360's Type 1 SVC, SVC 255.
Split into simpler sentences: All ATS/360 input/output operations utilized EXCP exclusively. Task switching was accomplished asynchronously as an extension of ATS/360's EXCP appendages and synchronously as an extension of ATS/360's Type 1 SVC, SVC 255.