Archive for December, 2015

Today I realized we write our numbers backwards.

Saturday, December 26th, 2015

We write our letters from left to right, but we write our numbers from right to left.

When we write the number 100, we write the digits 1, 0, 0 from left to right, but that’s not what I mean.

When we add up a series of numbers, we align them right shifted so that all the positions with the same value are lined up in a row. In order to make that work, we effectively write the numbers from right to left.

Wouldn’t it make more sense to write the least significant digit first, so 100 would be written 001 so that we could write from left to right and the numbers would still line up correctly. Adding 100 and 2036 for example…



Thursday, December 24th, 2015

A few months ago I bought a bought a netgear R6250 router. It does ac, and when I had something that did ac, it was wicked fast.

Overall I was less impressed with it than the actiontek or whatever it was router that verizon gave me with my FIOS, but the fios router didn’t even do 802.11n so it was time to upgrade.

It’s good enough, it works mostly, doesn’t need to be rebooted all that often but I found one extremely annoying problem with the interface that drove me bonkers.

It has a port forwarding feature like I expect most routers do nowadays, which allows me to connect to the various machines I have on my network when I am away from home. I’m that rare breed that does system administration from my phone.

But the port forwarding feature had a weird limitation. You couldn’t forward to the same numbered port on two different machines.

So if I had 2 machines running ssh on port 22, I couldn’t assign two different external ports to be forwarded (say 22 and 23) to forward to port 22 on two different machines. It just wouldn’t let me do it.
There’s no technical reason you can’t do it, my fios router let me do it, but the UI would not allow the reuse of the number.
I fiddled with the javascript where the restriction is enforced and I saw it was just an arbitrary rule in the UI.

I didn’t bother enough to write a request that would go past the UI and try and submit the request I wanted to the router itself, because it was easier just to have my machines listen for ssh connections on different ports, but that always annoyed me.
I wrote a letter to tech support and I think they basically said “suck on it.”

Well here I am a few months later logging into my router’s admin page and it says there’s a firmware upgrade. So I do it and of course the first thing I try and do is map two ports to the same port on different machines, and voila! It worked!

They fixed it. They actually fixed it.

Yay netgear.

For reference, the old firmware version was V1.0.3.6_10.1.3 and it upgraded to V1.0.4.2_10.1.10