Cisco Gigabit Switch Router 12008 Installation And Configuration Manual page 58

Overview of the Cisco 12008
•
Up to 2 GB of SDRAM on two PC133-compliant, dual in-line memory modules
(DIMMs). 512 MB of SDRAM is the default shipping configuration. SDRAM is field
replaceable.
•
Two MB of SRAM for secondary CPU cache memory functions. SRAM is not user
configurable or field replaceable.
•
Two MB of NVRAM. NVRAM is not user configurable or field replaceable.
•
Additional memory components used by the system, including onboard Flash memory
and up to two Flash memory cards.
•
Air-temperature sensors for environmental monitoring.
The Cisco IOS software images that run the Cisco 12000 series Internet Router system are
stored in Flash memory. Two types of Flash memory ship with the PRP:
1 Onboard Flash memory — Ships as a single in-line memory module (SIMM). This
Flash memory contains the Cisco IOS boot image (bootflash) and is not field
replaceable.
Flash disk— The PRP ships with a Flash disk that can be installed in either Flash disk
2
slot. (See Figure 1-12.) The Flash disk contains the Cisco IOS software image.
Storing the Cisco IOS images in Flash memory enables you to download and boot from
upgraded Cisco IOS software images remotely, or from software images that reside in PRP
Flash memory.
Cisco 12000 series Internet Routers support downloadable system software for most Cisco
IOS software upgrades. This enables you to remotely download, store, and boot from a new
Cisco IOS software image. The Cisco IOS software runs from within the PRPs SDRAM.
Figure 1-12 shows the locations of the various hardware components on the PRP.
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Cisco 12008 Gigabit Switch Router Installation and Configuration Guide