What is relation among flash, bootflash and harddisk in Cisco router?

[wfqk]

Hi Any one can explain what is relation among flash, bootflash and harddisk in Cisco router? especially in ASR1000 or other device? Thank you

[Reza Sharifi]

Hi,

Most Cisco devices don't have hard disks, they only have flash where the IOS and other boot file reside. The flash size varies from megabytes to multi gigabytes. Other vendors devices like Juniper  have both flash and hard disks. They use flash for booting the device and the hard disk for storing log files since they usually come in larger size.(30gig, 60gig, etc..).

HTH 

[wfqk]

Thank you so much for your reply. 

So we can think they all are storage room, and the different thing among them is different size, right?