The 24LC1026 is a 128Kx8 (1024K bit) Serial Electrically Erasable PROM, capable of operation across a broad voltage range (1.7V to 5.5V). It has been developed for advanced, low-power applications such as personal communications or data acquisition.
The AT24C256 is a 32K byte, 8-pin EEPROM IC. As we know EEPROM stands for Electrically Erasable Programmable Read-Only Memory, we can store information on this IC and it will remain there even when the power is turned off just like your pen drive.