Cisco Gigabit Switch Router 12008 Installation And Configuration Manual page 52

Overview of the Cisco 12008
DRAM
The extended data output (EDO) dynamic random-access memory (DRAM) on the GRP
stores routing tables, protocols, and network accounting applications, and runs the
Cisco IOS software. The standard (default) GRP DRAM configuration is 64 megabytes
(MB) of EDO DRAM, which you can increase up to 256 MB through DRAM upgrades.
The Cisco IOS software runs from within GRP DRAM.
Two DRAM DIMM sockets are incorporated into the GRP, as shown in Figure 1-10. These
sockets, labeled U39 (P4 DRAM bank 1) and U42 (P4 DRAM bank 2), enable you to
configure DRAM in increments ranging from 64 MB to 256 MB. Table 1-3 lists the
available upgrade configurations for DRAM on the GRP.
Table 1-3
Total DRAM
64 MB
128 MB
128 MB
256 MB
1. 64 MB is the standard (default) DRAM configuration for the GRP.
Caution
(ns) devices. Do not attempt to install memory devices in the DIMM sockets that do not
meet these requirements.
SRAM
SRAM provides secondary CPU cache memory. The standard GRP configuration is
512 KB. Its principle function is to act as a staging area for routing tables update
information to and from the line cards. SRAM is not user configurable or field-upgradeable.
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Cisco 12008 Gigabit Switch Router Installation and Configuration Guide
DRAM Configurations
Product Numbers
1
MEM-GRP/LC-64(=)
MEM-GRP/LC-64(=)
MEM-GRP/LC-128(=)
MEM-GRP/LC-256(=)
To prevent memory problems, DRAM DIMMs must be 3.3 V, 60-nanosecond
DRAM Sockets Number of DIMMs
U39 (bank 1) 1 64-MB DIMM
U39 (bank 1) and 2 64-MB DIMMs
U42 (bank 2)
U39 (bank 1) 1 128-MB DIMM
U39 (bank 1) and 2 128-MB DIMMs
U42 (bank 2)