| 摘要 |
PROBLEM TO BE SOLVED: To vary CD-ROM access timing in a guiding point in compliance with a mean access time in a CD-ROM deck so as to suppress an error in guiding distance. SOLUTION: When an access demand to a CD-ROM 7 is generated, a CPU 10A increases the number of accesses, starts a timer, and issues a reading demand to the CD-ROM deck. After reading is finished, a timer is turned off so as to measure the time from the issue of the reading demand to the finish of reading, and the data transfer time is subtracted from the measured time, so that only the access time is found. A mean access time is found from the total of the access times up to that time and the number of accesses, and a distance obtained by multiplying vehicle speed and the mean access time is added to the guiding point, and consequently, the guide point corresponds to the access finish time point in the CD-ROM deck. |
