Storage device for suspending program operation and performing read operation and operating method thereof

A storage device comprising:

• a memory device for storing data, wherein the memory device includes a page buffer in which data is temporarily stored;
• a memory controller for controlling the memory device,
• wherein the memory controller includes a request transmitter configured to provide a program suspend request for suspending a program operation, when the memory device receives a read request from a host while the memory device is performing the program operation, and
• wherein the memory controller includes a command controller configured to generate and output a program suspend command, based on the program suspend request, and output a cache read command or normal read command, based on a number of commands of a command queue in which a command corresponding to the read request received from the host is queued;
• and
• program data storage for communicating with the memory device, wherein the program data storage stores data output from the memory device,
• wherein the memory device is configured to output program data stored in any one latch among a plurality of latches included in the page buffer to the program data storage and allocate the latch from which the program data is output as a cache latch for performing a cache read operation corresponding to the cache read command.