What is Boot Media device ?

[Ontapforrum]

I think as far Data Ontap 8 onwards is concerned :The OS (ontap operation system) is stored on the CF/USB flash boot_media device in the controller (depending upon the Model). The root aggregate contains the root volume that stores OS related stuff like configuration and logs. However it boots from boot_media device. Thanks!

[CHRISMAKI]

Not just v8+, I've had to do 3am change windows replacing the CF media gone bad in 7-mode gear...can't remember the exact model, ugly beige bezel with DS14's attached.

[Sebastian_Goetze]

Just to mention: the whole of ONTAP itself is not stored on the boot medium, but on vol0 in the root aggregate.

But it is started from the pre-boot-environment that's stored on the Boot Medium. I.e. there's kernel(s) and drivers and stuff, but all of ONTAP, let alone 2 versions ("images") of it, don't fit on it.

[Sebastian_Goetze]

Essentially it's what is read and started to get you to the Pre-Boot-Environment ("Loader"), from which you can start ONTAP, get into maintenance mode and so on.

As others mentioned, nowadays it's a internal "USB"-flash-device.

Previously it used to be a CF-card.

Before that it was a floppy disk.  (Kernels used to be small back then, also...)   🙂