the IO state buffer comprises multiple elements for storing context information of IO requests, and each element corresponds to an IO request; the context information comprises a module calling sequence generated by a Central Processing Unit (CPU) in a Solid State Disk (SSD) controller, wherein the module calling sequence indicates a functional module scheduling sequence corresponding to each of the IO requests; and

the pipeline controller is configured to perform pipeline control on the IO requests according to the module calling sequence of each of IO requests;

wherein the pipeline controller comprises:

a first processor, configured to read, after receiving an element addition notification sent by the CPU and due to a new IO request is received by the SSD, a module calling sequence in the newly added element, determine a first functional module to be called according to the module calling sequence, and send an IO request corresponding to the newly added element to the first functional module to be called for operation processing; and

a second processor, configured to receive an operation completion notification sent by a functional module in a system, read from an IO state buffer a next functional module to be processed corresponding to an operation completed IO request, and send the operation completed IO request to the next functional module to be processed; and determine a current IO request to be processed by an operation completed functional module according to a scheduling algorithm, and send the current IO request to be processed to the operation completed functional module for operation processing.