1. A digital device provided with an operating system for executing in parallel a plurality of tasks each managed as one execution unit by program execution means, comprising: task attribute information storage means for storing an attribute of an function which constitutes said task; program execution means for transmitting information on an attribute of a function under execution, and for querying about execution of an abort to a task to which said function belongs; task execution determination means for determining whether or not the abort is executed based at least on the attribute of the function under execution responsive to the query from said program execution means on the execution of the abort; and task attribute recognition means for storing the attribute of the function currently under execution in said task attribute information storage means, based on the information on the attribute of the function transmitted from said program execution means, and for returning the attribute of the function stored in said task attribute information storage means in response to a query from said task execution determination means about the attribute of the function currently under execution.