Wikipedia:Reference desk/Archives/Computing/2012 April 26

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April 26

Double OS and double hibernate?

If you have two OSs in one computer, can you put both to hibernate and choose which want you to wake? That would be a kind of GRUB loader. 14:50, 26 April 2012 (UTC) — Preceding unsigned comment added by 88.8.68.89 (talk)

In principle, yes - but it depends on the order of your bootloaders. For example, the Windows bootloader won't give you a choice if you hibernated (presumably to reduce the possibility of making changes 'behind its back' with potentially deletrious consequences on resume) - I've not paid enough attention to notice if any Linux distributions do the same with GRUB. 131.111.255.9 (talk) 16:11, 26 April 2012 (UTC)

To add to that, you would have to have 2 swap partitions because of hibernation suspending to RAM

Classful networking and CIDR

I more or less know what classful networking and CIDR are. And I know CIDR came after classful and makes use of a subnet mask. So my questions: did subnet masks exist before CIDR or were they introduced for CIDR? If they were introduced for CIDR does this mean the IP protocol had to be changed? If they already existed what were they used for and, again, were any changes needed to be made to the IP protocol?

Thanks and sorry for all the question. Im really just starting networking and I cant help getting caught up in all the details even though I may not need them right now. --TuringMachine17 (talk) 22:47, 26 April 2012 (UTC)

We have articles on both CIDR and Subnet masks. From what I can tell from the article, they came about at the same time. RudolfRed (talk) 00:41, 27 April 2012 (UTC)

I saw this yesterday, and was about to answer they were different, but from what our articles suggest, they seem to have come about together. When I hear CIDR I think the notation (/16) but obviously it's broader.

But there's a caveat. While the internet edge routers wouldn't use subnetting like we think about it today, the RFC introducing CIDR talks about subnetting. What's special about CIDR is variable-length subnetting. Whether that difference is meaningful depends on whether or not those early networking devices/stacks respected other subnets before CIDR was contemplated. That I do not know. But the term "subnet" was used to describe the fixed subnets of classes. A class A range could be expressed as a subnet, and that terminology was used back in 1993. Shadowjams (talk) 16:10, 27 April 2012 (UTC)