Cisco 12404 Installation And Configuration Manual page 262

Product Architecture
SRAM
NVRAM
Caution
Flash Memory
PCMCIA Slots
Cisco 12404 Internet Router Installation and Configuration Guide
A-10
The SRAM provides secondary CPU cache memory. The standard GRP
configuration is 512 KB. The principle function of SRAM is to act as a staging
area for routing table update information to and from the line cards. SRAM is not
able to be upgraded or configured.
The system configuration, software configuration register settings, and
environmental monitoring logs are contained in the 512-KB NVRAM, which is
backed up with built-in lithium batteries that retain the contents for a minimum of
5 years. NVRAM is not able to be upgraded or configured
Before you replace the GRP in the system, back up the running configuration to a
Trivial File Transfer Protocol (TFTP) file server or an installed Flash memory
card so you can retrieve it later.
If the configuration is not saved, the entire configuration is lost inside the
NVRAM on the removed GRP and you must re-enter the entire configuration
manually.
This procedure is not necessary if you are temporarily removing a GRP; lithium
batteries retain the configuration in memory until you replace the GRP in the
router.
Both the onboard and PCMCIA card-based Flash memory allow you to remotely
load and store multiple Cisco IOS software and microcode images. You can
download a new image over the network or from a local server and then add the
new image to Flash memory or replace the existing files. You can then boot the
routers either manually or automatically from any of the stored images. Flash
memory also functions as a TFTP server to allow other servers to boot remotely
from stored images or to copy them into their own Flash memory.
The GRP has two PCMCIA slots. Either slot can support a Flash memory card or
an input/output (I/O) device as long as the device requires only +5 VDC.
Appendix A Technical Specifications
OL-11636-01