Difference Between Flash Memory and NVRAM ?

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Aug 6th, 2007
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While running the show version command on a Cisco 2600 series router during a Live Lab session I see that it reports :-

32K bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

Aren't these two memory types not essentially the same ? Why is there separate NVRAM and System Flash memory in the router ? Cannot the system startup config files and IOS images all not just be stored in Flash memory ? I am puzzled as to why the separate NVRAM memory is required by the router.

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Richard Burts Mon, 08/06/2007 - 12:30
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In current implementations the distinction between the memory types gets smaller and there are some models in which it is possible to store the config file in flash and to boot the router using the config in flash rather than in NVRAM (I recently tested this in an 1841 router). But historically the types of memory used (SRAM EPROM) were different, had different capacities, and different operating characteristics. So the current distinction of NVRAM and Flash are there mostly for historical reasons.



sibtain-raza Tue, 06/05/2012 - 18:08
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dear rossua994, can i sum up your answer that flash memory is just have higher capacity than the NVRAM, but by convention in routers we save startup configurations in NVRAM and IOS in the flash....but literally both are permanent memories in case..is that you saying exactly..??

i am still confused..hope to get the reply soon..!!


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