正大教育计算机培训中心
Note:
RAM—Packet buffers, running configurations, running Cisco IOS
ROM—POST, ROM monitor, baby Cisco IOS (Rxboot)
NVRAM—Backup configurations, config register
Flash—Cisco IOS
Flash memory is nonvolatile. It behaves like a file system. It is more expensive than
NVRAM. It is readable and writeable. The 2500 routers run from Flash. If it is running
Cisco IOS from Flash, then the Flash is in the readable state. Use the boot system
command to boot Cisco IOS from a TFTP server so the 2500 can run from RAM if you
need to write or erase Flash online.