An embedded operating system is the (71) program that manages all the other programs in an embedded device after initial load of programs by a(an) (72). It normally guarantees a certain capability within a specified (73) size and (74) constraint as well as with application programs. It also normally has small foot print including initial boot loader, OS kernel, required device drivers, (75) for the user data and so forth. It has very-likely structure of a normal operating system however mainly differentiated by some factors such as type of pre-installed device, functional limits, taking designed job only.
A．driver
B． application
C．kernel
D．boot loader