Storage device that writes data from a host during garbage collection

A method of operating a storage device including a buffer that comprises a volatile memory, and a nonvolatile memory including a plurality of blocks, the storage device configured to perform read and write operations based on read and write commands output from a host, wherein each of the blocks includes a plurality of pages, the method comprising:

• associating one or more blocks of the nonvolatile memory with a first namespace such that data associated with the first namespace are selectively stored therein;
• associating other one or more blocks of the nonvolatile memory with a second namespace such that data associated with the second namespace are selectively stored therein;
• carrying out garbage collection by reading data from one or more pages of a target block of the garbage collection and selectively copying valid data included in the read data to another block;
• determining during the garbage collection an amount of invalid data included in the read data;
• and
• receiving, in the buffer during the garbage collection, first write data from the host up to a first size which depends on the determined amount of invalid data,
• wherein the garbage collection and the determining of the amount are carried out independently with respect to each of the first and second namespaces, and
• wherein third write data associated with the first namespace and fourth write data associated with the second namespace are received in the buffer, up to a maximum amount which is determined based on a sum of the determined amount for the first namespace and the determined amount for the second namespace.