Module − SIMM (72−pin, 60 ns, with or without parity). If SIMM is non−parity, total DRAM can be up to 18 MB. If SIMM is with parity, total DRAM can be up to 16 MB (on−board 2 MB will be disabled).
Note: The Cisco 1605−R Series Router has 8 MB on−board. Therefore, total DRAM can be up to 24 MB on that router. For more information, see Comparison of Cisco 1601, Cisco 1604, and Cisco 1605−R Memory Architectures.
To install or replace the DRAM, see Installing or Replacing the DRAM SIMM in Cisco 1600 Series Routers.
PCMCIA Flash is the only way to permanently store and move a complete Cisco IOS software image, backup configurations, or any other files.
PCMCIA Flash on the Cisco 1600 Series router is implemented using one slot for Fast PC cards (up to 16MB).
The PCMCIA Flash card on the Cisco 1600 Series router uses the Filesystem Class "B". This is the same type used for the Cisco 1000 Series Router and Cisco 3600 Series Router. For PCMCIA format compatibility information, see PCMCIA Filesystem Compatibility Matrix.
NVRAM is used for writeable permanent storage of the startup configuration. It is also used for permanent storage of hardware revision and identification information, as well as Media Access Control (MAC) addresses for LAN interfaces. It is a battery−backed Static RAM (SRAM). The lifespan of NVRAM is specified in the maximum number of writes and a maximum time limit. NVRAM size is 8 KB.
BOOT ROM is an Erasable programmable read−only memory (EPROM) used for permanently storing startup diagnostic code (ROM Monitor), and RxBoot. Boot ROM size is 2 MB. The Cisco 1600 Series Router runs RxBoot from Boot ROM.
For information on upgrading the Boot ROM, see Upgrading the Boot ROMs in Cisco 1600 Series Routers.
Registers are small, fast memory units used for storing special purpose information, such as interrupt status, currently executing instruction, and so on. The location of registers depends upon their use. For example, the main processor contains the instruction register and other control registers. UART contains its own status register such as other I/O devices and data read/write registers on various components. The main processor also contains general purpose registers for integer and floating point data used in an instruction execution.
The different types of memory can be seen in the output of the show version command:
Router−1600#show version
Cisco Internetwork Operating System Software
IOS (tm) 1600 Software (C1600−SY−L), Version 12.1(7), RELEASE SOFTWARE (fc1) Copyright (c) 1986−2001 by cisco Systems, Inc.
Compiled Thu 22−Feb−01 12:56 by kellythw
Image text−base: 0x08041D10, data−base: 0x02005000
ROM: System Bootstrap, Version 11.1(7)AX [kuong (7)AX], EARLY DEPLOYMENT RELEASE SOFTWARE (fc2)
ROM: 1600 Software (C1600−BOOT−R), Version 11.1(7)AX, EARLY DEPLOYMENT RELEASE SOFTWARE (fc2)
Router−1600 uptime is 2 hours, 49 minutes
System returned to ROM by reload
System image file is "flash:/c1600−sy−l.121−7.bin"
cisco 1603 (68360) processor (revision C) with 13824K/4608K bytes of memory. Processor board ID 05317740, with hardware revision 00000000