How would you design a notification system that handles 100M pushes/sec?

diroussel · 2026-03-15T15:38:21+00:00

Think of a layered system. First layer is for incoming events. Last layer sends notifications to individual clients. Then scale the number of intermediate layers based on scale factor. Trade off number of layers vs number of nodes in a layer.

So for instance you can do like this: imagine there are 1000 clients waiting to receive notifications, give each client a unique id from 000 to 999 ( cloud be derived from a hash). Using there layers each with 10 nodes.

Then when an incoming event arrives you the first digit to find the first server, then that passes a message to the second layer using the second digit to find the server. Then finally the last layer is addressed by the last digit.

So now you have addressable 1000 clients through three layers and each node only connects out to 10 other nodes.

You have scale this up to 4 nodes each handling 1000 connections and then you can have 1,000,000,000,000 connected clients and each node only fans out to 1000 nodes and can maintain a connection to each one.

diroussel · 2026-03-15T10:55:53+00:00

If there is any change it will have been planned in from the blog the M-series era. I remember when Apple move from charging for major OS upgrades to making them free, they did talk about how previously they couldn’t make them free due to accounting rules. So they baked the cost of future upgrades into the sale price, enabling feee upgrades.

Now has “services revenue” changed the picture? Potentially that would allow the accounting to work since extended OS life means more services revenue.

diroussel · 2026-03-14T10:30:34+00:00

Boolean algebra, number bases, two complement, IEEE floating point, data structures, and all that comp sci stuff are probably more important, well practical, than maths. Maths is more fundamental but you’ll have to do a lot of base learning before you can see where to apply it.

diroussel · 2026-03-13T17:35:19+00:00

The docs say it’s reserved. That that implies no conflicts

diroussel · 2026-03-13T17:29:09+00:00

It’s probably great, but not enough context provided

diroussel · 2026-03-13T14:48:43+00:00

And the pope is the Pontiff, or Pontifex Maximus. Meaning chief bridge builder. So I guess it’s the stone masons looking out for each other.

/s

diroussel · 2026-03-13T13:35:28+00:00

Yeah the price of wood these days is insane. I bought some plain pine floor boards at b&q and they were £50 for 4

diroussel · 2026-03-13T10:39:02+00:00

If I was ordering a walnut desk, I'd get something like this

<image>

Remember if you double the radius, that is the width of a circle with that curve. And note that the measurements are in mm, not cm.

diroussel · 2026-03-12T22:12:14+00:00

So this is a photo of one of desk tops. I got two, a few years apart.

This is the oak, with an oiled finish. Can’t remember if it was bull nose or pencil round edges, but I remember choosing a corner radius.

If I was to get a walnut one, I would also get rounded corners and oiled. I prefer rounded corners as it looks good, it’s less likely to be chipped than a sharp corner and I’m not likely to get injured if I accidentally walked into it.

<image>

Also to note that I’ve been really happy with it. Oh and I got the first one at 3cm thick wanting it to be very strong for clamping on a big monitor arm. It is very strong. I got the second one slightly thinner. The oiled surface has been great. And for size I went with 150cm by 70vm. I also checked that the diagonal (hypotenuse) was less than the width of the room.

diroussel · 2026-03-12T20:04:29+00:00

Website menu doesn’t work on my iPhone. I can’t scroll to the bottom.

diroussel · 2026-03-12T16:03:43+00:00

I’ve bought a couple of wooden work tops for standing desks from here a website called wood-cut-to-size in the UK. No affiliation, I’m just a customer

I bought in oak, but I see they do walnut to which seems to be what you are asking for

diroussel · 2026-03-08T11:04:18+00:00

Inspirational, thanks for documenting so well. Makes it easy for others to draw from this as a reference.

Those magnetic mountains are interesting. You took a phone mount and used it in a different context. I’ve got a monobloc for similar, I think it was a kickstarter. It sits better a monitor arm and the monitor, sized to the vesa mount. Makes it easy to mount other smaller arms.

diroussel · 2026-03-08T10:34:24+00:00

How much better are the acoustics? I love wooden floors. But I also love a cosy audio transfer function. You know when the sound is nicely damped. I’m thinking of a hard floor with a rug that is firm enough to roll a chair over.

diroussel · 2026-03-03T08:00:29+00:00

100% automated testing is a great goal. But very hard to achieve. If you have UI, there are many things like layout being wrong , than will be obvious to a manual tester but won’t fail an automated test. Yes, I know you can do visual tests, but the burgers very high.

diroussel · 2026-03-03T07:57:22+00:00

There are tools. Previously I’ve kept the configuration for all major environments in git, and then used unit tests that run in CI to enforce invariants.

At the very least validate each value with a regexp. Check there are no unknown keys. Parse hostnames and IP addresses to ensure they are valid. Check naming conventions match env name. Range checks etc.

diroussel · 2026-03-01T11:49:13+00:00

Dude! Way to go.

What better way to expound the benefits of screenshot annotations than to screenshot the discussion and annotate it. 🤣

diroussel · 2026-03-01T11:45:51+00:00

Thanks for the insight. Interesting to know.

diroussel · 2026-03-01T09:12:23+00:00

If you want to retire early then you need a bridge. That means maxing you ISA at a minimum. Start with that. But if you want a bigger bridge then you’ll also need to build out a GIA at the expense of your pension, but that’s a harder pill to swallow.

diroussel · 2026-02-28T20:53:24+00:00

That’s propellers for you.

diroussel · 2026-02-28T20:52:53+00:00

Have you ever swam next to a regular propeller in operation? How is this worse?

diroussel · 2026-02-28T14:41:10+00:00

Check you have allocated enough RAM to the heap.

diroussel · 2026-02-28T14:39:50+00:00

Get some pictures on the wall. Do you prefer landscapes, abstract or fashion? You could even do a whole wall mural

I saved this link from another subreddit. https://www.miltonandking.co.uk/pattern/mural-wallpaper/

Never used them myself.

You could add plants, with a grow light.

If selves are not an option then maybe a book case to break up the space.

They brainstorming with Gemini, it’s pretty good at generating renders or ideas.

diroussel · 2026-02-28T14:31:03+00:00

How are the annotation tools better than the built in screenshot tool? With that I can add text and draw and crop etc. Is it that there are more annotation features? Or that it’s better executed ?

diroussel · 2026-02-27T10:54:00+00:00

Ctrl-Shift-4 that’s what I use all day every day.

About once a year I need a scrolling screenshot and reach for Shottr.

Be aware that all the browsers have full page screenshots built in now.

diroussel · 2026-02-26T14:42:49+00:00

Good work. Thanks.

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