64bit vs 32bit OS

[Arjun Dabol]

hello , when we say an OS is 64bit what does that "64 bit"  mean ? what it does with respect to functionality ?

[Nicolas Fevrier · Accepted solution]

Hi,

in the context of IOS XR operating system, we have currently three flavors (I simplify):

- CRS, ASR9000 are based on a QNX microkernel. It's a 32-bit infrastructure, which reflects on the maximum memory space we can address for each process/thread.

- XRv is running over linux but is also 32 bit

- NCS6000 is running over a linux and a type2 hypervisor (kvm/qemu) and is 64-bit. The XRv-9000 virtual router that will be available this summer is also based on the same infrastructure. The memory space addressable is much wider, hence the scalability is way higher. That's particularly sensible in the Route Reflector role.

We have plans to also move the ASR9000 to 64 bit in medium term, plans need to be solidified, a bit too early to say when it will be available.

Hope it answered your question,

N.

[Arjun Dabol]

which reflects on the maximum memory space we can address for each process/thread - See more at: https://supportforums.cisco.com/discussion/12545066/64bit-vs-32bit-os#sthash.S2OFU4Sr.dpuf

[Arjun Dabol]

Many Thanks : when you say : which reflects on the maximum memory space we can address for each process/thread. -

Does that mean for a 32 bit system - OS will allocate a max of 32 bits at a given time ? is'nt it too less? Becoz I think for XR - a threshold of every process is 300 MB - how is it related with 32 bit concept ?

If you can help me in understand that , will be great.

Thx again

[Nicolas Fevrier]

Hi,

I'm a bit surprised to read 300MB max per process since I have very different numbers in mind.

I remember that back in the 4.1.x days, we increased the max size of the virtual memory to 2.5 GB (was on ASR9K).

Cheers,

N.

[smailmilak]

Hi Nicolas,

when can we expect the release of 6.1 for A9K and will it have true ISSU with RP2 and Tomahawk Transport (TR) LC?