Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual page 47

Caution Cisco Systems strongly recommends that you use only Cisco-approved memory.
To prevent memory problems, SDRAM DIMMs must be +3.3VDC, PC133-compliant
devices. Do not attempt to install other devices in the DIMM sockets.
SRAM
SRAM provides 2 MB of parity-protected, secondary CPU cache memory. Its principal
function is to act as a staging area for routing table updates and for information sent to and
received from line cards. SRAM is not user configurable and cannot be upgraded in the
field.
NVRAM
NVRAM provides 2 MB of memory for system configuration files, software configuration
register settings, and environmental monitoring logs. This information is backed up with
built-in lithium batteries that retain the contents for a minimum of 5 years. NVRAM is not
user configurable and cannot be upgraded in the field.
Flash Memory
Flash memory allows 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 then can boot
the routers either manually or automatically from any of the stored images.
Flash memory also functions as a Trivial File Transfer Protocol (TFTP) server to allow
other servers to boot remotely from stored images or to copy them into their own Flash
memory. The onboard Flash memory (called bootflash) contains the Cisco IOS boot image,
and the Flash disk contains the Cisco IOS software image. A 64-MB ATA Flash disk ships
by default with the PRP. Table 1-4 lists the supported Flash disk sizes and their Cisco
product numbers.
Table 1-4 Supported Flash Disk Sizes and Product Numbers
1
Flash Disk Size
2
64 MB
Physical and Functional Overviews
Product Number
MEM-12KRP-FD64=
Product Overview 1-19