A method of scheduling jobs in a storage device, the method comprising: pre-defining an operation time table that represents a relationship between a plurality of operations (RDO, WRO, ERO) of the storage device and expected operation times (TR1 to TRN, TW1 to TWN, TE1 to TEN) thereof, wherein each said operation time (TR1 to TRN, TW1 to TWN, TE1 to TEN) is a time that is expected to be required to perform a respective said operation (RDO, WRO, ERO); receiving a plurality of scheduling requests (SREQ) for using or accessing the storage device, each said scheduling request (SREQ) associated with a respective timestamp (TS1 to TSN) and with a respective job (JOB 1, JOB2) having at least one operation (RDO, WRO, ERO), wherein each of the plurality of timestamps (TS1 to TSN) represents an accumulated time in which a respective one of a plurality of job performers (PFMR1 to PFMRN) has used the storage device cumulatively to perform one or more jobs (JOB1, JOB2); performing a first job of the plurality of jobs having a first operation; while the first job is being performed, pre-updating the accumulated time of a first timestamp for the first job based on the first operation and the pre-defined operation time table; and while the first job is being performed, pre-performing a scheduling operation for selecting a second job from the plurality of jobs (JOB 1, JOB2) to be performed subsequent to the first job based on the plurality of scheduling requests (SREQ) and the plurality of timestamps (TS1 to TSN), wherein the pre-performing the scheduling operation for selecting the second job includes: searching for a second timestamp having a minimum value by comparing the plurality of timestamps (TS1 to TSN) with each other; and selecting a job associated with a scheduling request (SREQ) corresponding to the second timestamp having the minimum value, the selection from among the plurality of scheduling requests (SREQ), as the second job. pre-defining an operation time table that represents a relationship between a plurality of operations (RDO, WRO, ERO) of the storage device and expected operation times (TR1 to TRN, TW1 to TWN, TE1 to TEN) thereof, wherein each said operation time (TR1 to TRN, TW1 to TWN, TE1 to TEN) is a time that is expected to be required to perform a respective said operation (RDO, WRO, ERO); receiving a plurality of scheduling requests (SREQ) for using or accessing the storage device, each said scheduling request (SREQ) associated with a respective timestamp (TS1 to TSN) and with a respective job (JOB 1, JOB2) having at least one operation (RDO, WRO, ERO), wherein each of the plurality of timestamps (TS1 to TSN) represents an accumulated time in which a respective one of a plurality of job performers (PFMR1 to PFMRN) has used the storage device cumulatively to perform one or more jobs (JOB1, JOB2); performing a first job of the plurality of jobs having a first operation; while the first job is being performed, pre-updating the accumulated time of a first timestamp for the first job based on the first operation and the pre-defined operation time table; and while the first job is being performed, pre-performing a scheduling operation for selecting a second job from the plurality of jobs (JOB 1, JOB2) to be performed subsequent to the first job based on the plurality of scheduling requests (SREQ) and the plurality of timestamps (TS1 to TSN), wherein the pre-performing the scheduling operation for selecting the second job includes: searching for a second timestamp having a minimum value by comparing the plurality of timestamps (TS1 to TSN) with each other; and selecting a job associated with a scheduling request (SREQ) corresponding to the second timestamp having the minimum value, the selection from among the plurality of scheduling requests (SREQ), as the second job. searching for a second timestamp having a minimum value by comparing the plurality of timestamps (TS1 to TSN) with each other; and selecting a job associated with a scheduling request (SREQ) corresponding to the second timestamp having the minimum value, the selection from among the plurality of scheduling requests (SREQ), as the second job.