Abstract: A method of managing a page buffer of a non-volatile memory device comprises programming least significant bit (LSB) page data from an LSB page buffer into a page of memory cells, and retaining the LSB page data in the LSB page buffer until most significant bit (MSB) page data corresponding to the LSB page data is programmed in the page.

Abstract: A semiconductor device with flash memory includes; a log type determining unit configured to select log type from among a plurality of log types with respect to a log block storing program data requested to be programmed in the flash memory and generate a control signal indicating information indicating the selected log type, and a plurality of log units configured to store program data in the log block having a corresponding log type in response to the control signal, wherein the log type determining unit converts a first type log block formed by a first log type and included in a first type log unit from among the plurality of log units into second type log block formed by a second log type and converts the log block included in a second type log unit from among the plurality of log units into the first type log blocks, the first loge type being different from the second log type.