Operating method of storage device

1. An operating method of a storage device which includes a nonvolatile memory, comprising:

performing a first program operation on selected memory cells of the nonvolatile memory, and storing a first time when the first program operation is performed;

adjusting a program parameter according to a difference between the first time and a second time; and

performing a second program operation on the selected memory cells using the adjusted program parameter,

wherein the second time is a time when the second program operation is performed,

wherein during the second program operation, a program voltage is iteratively applied to a word line connected to the selected memory cells,

wherein the program parameter comprises an increment of the program voltage iteratively applied to the word line, and

wherein the adjusting comprises increasing the increment as the difference increases.

2. The operating method of claim 1 , further comprising:

storing the second time;

readjusting the program parameter according to a difference between the second time and a third time; and

performing a third program operation on the selected memory cells using the readjusted program parameter,

wherein the third time is a time when the third program operation is performed.

3. The operating method of claim 1 , further comprising:

performing a read operation on the selected memory cells when a reset of the storage device occurs after the first program operation is performed and before the second program operation is performed,

wherein the difference is calculated according to a result of the read operation.

4. The operating method of claim 1 , wherein the first time is stored in the nonvolatile memory, and

wherein during the performing of the second program operation, the first time is read from the nonvolatile memory and the program parameter is adjusted according to the difference between the read first time and the second time.

5. The operating method of claim 1 , wherein the first program operation and the second program operation comprise programming the selected memory cells using a same data.

6. The operating method of claim 1 , further comprising:

receiving a clock signal,

wherein an internal time of the storage device is counted according to the clock signal, and

wherein the first and second times are acquired based on the internal time.

7. The operating method of claim 6 , wherein the clock signal is a signal that periodically transitions and indicates lapse of time or information on an actual time.

8. The operating method of claim 1 , wherein the first program operation programs the selected memory cells to at least two states, and the second program operation programs the selected memory cells to the same at least two states.

9. An operating method of a storage device which includes a nonvolatile memory, comprising:

performing a first program operation on selected memory cells of the nonvolatile memory, and storing a first time when the first program operation is performed;

adjusting a program parameter according to a difference between the first time and a second time; and

performing a second program operation on the selected memory cells using the adjusted program parameter,

wherein the second time is a time when the second program operation is performed, and

wherein the selected memory cells are programmed by the first program operation and the second program operation without an erase operation between the first program operation and the second program operation.

10. An operating method of a storage device which includes a nonvolatile memory, comprising:

performing a first program operation on selected memory cells of the nonvolatile memory, and storing a first time when the first program operation is performed;

adjusting a program parameter according to a difference between the first time and a second time; and

performing a second program operation on the selected memory cells using the adjusted program parameter,

wherein the second time is a time when the second program operation is performed, and

wherein the first program operation programs the selected memory cells to at least two states, and the second program operation programs the selected memory cells to more than the at least two states.