Hi,
Catalyst switches that run CatOS by default operate in binary configuration mode. When you operate in binary configuration mode, most user settings are automatically saved to NVRAM. Text mode typically uses less NVRAM or Flash memory space than binary configuration mode and thus you use text mode if the configuration is too large for storage in binary format in the NVRAM.
Although you must issue the write memory command while you operate in text mode to save the configuration in NVRAM, you can use the "set config mode text auto-save" command in order to automatically save the text configuration in NVRAM.
http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.1/configuration/guide/flash.html#wp1025004
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008015bfab.shtml
Console> (enable) set config mode
Usage: set config mode binary
set config mode text
Personally i prefer text mode as it is similar to this of an ordinary IOS router, plus it can be freely backuped and restored as a file.
Issue the write network command in order to upload the current configuration in NVRAM to a TFTP server.
Issue the configure network command in order to download a configuration file from a TFTP server directly into NVRAM.
HTH,
Mohammed Mahmoud.
