To provide a nonvolatile storage device and control method thereof which improve
convenience of portable devices by shortening initialization time. In generating
a data validity table at initialization, a control part firstly reads out a validity
flag and a second translation table. In the case where the validity flag is valid,
logical blocks in the second translation table are valid. For that reason, the
fourth table generation means can set all logical blocks in the second translation
table as being valid, in the data validity table. In a single reading as mentioned
above, the fourth table generation means can carry out setting with respect to
a plurality of logical blocks. Further, with respect to a partial logical block
which is set as being valid in the data validity table, it is possible to bypass
reading out the data validity flag of the block and proceed to operation of next
partial logical block.
