| 摘要 |
PURPOSE:To read various types of execution programs out of various external storage devices and execute them without changing a basic loader on a ROM by indicating the various external storage devices on a rewritable nonvolatile memory and storing diverse extended loaders for reading various types of execution programs out. CONSTITUTION:Storage media where various types of execution programs are stored are loaded on the external storage devices 1-1, 1-2, and 1-3. The ROM 2 which is a read-only memory, on the other hand, is stored with the basic loader and extended loaders are stored on the rewritable nonvolatile memory 3. Then one of the extended loaders is read out of the nonvolatile memory 3 and an execution part 6 reads one of the execution programs out of the external storage device 1-1, 1-2, or 1-3 indicated by the extended loader and executes the program. Consequently, the basic loader is read out of the ROM 2 and the execution programs are read out of the external storage devices 1-1, 1-2 and 1-3 and executed without changing the ROM.
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