Chill! I advised people who were upset because they could not get a Raspberry Pi Zero two days after it was announced. Despite the fact that tens of thousands of them had been produced, the supply (including all the MagPi magazines that included them in the issue) had been sold out.

Despair ran rampant on the Internet because (mostly) people who already had a Raspberry Pi A/B/B+ or Raspberry Pi 2 Model B could not get the very latest model.

Chill! I said and advised folks to remember the early days of the first Raspberry Pi when they spent hours trying to find some outlet that would have them in stock. After what seemed like forever, the manufacturing of the Raspberry Pis caught up with the demand, and people could get them whenever they wanted.

In the meantime, some people are selling (or trying to sell) those MagPi magazines on eBay for five to ten times what they paid, because they bought up copies knowing that someone would pay more money for the same magazine just to have the Raspberry Pi Zero NOW!

Chill! Because this is not the situation of the original Raspberry Pi, when the designers thought there was only a market for 1000… oh…10,000… oh… 100,000 units, and a couple of years later five million Raspberry Pis had been sold. This time, the Raspberry Pi Foundation must have known that they would sell hundreds of thousands of boards, and they will be prepared to manufacture enough to meet demand. It is just a matter of time.

Other than putting a hook on each of your Raspberry Pis and hanging them on your Christmas tree, what are you going to do with the RPi Zero? A friend of mine said he was interested in building a Beowulf high-performance cluster with them. "Think how small and cheap that would be," he said. "I can buy eight of them for only $40!"

True, but then, you'd have to buy some type of networking to allow them to communicate: either a wireless 802.11 device or a USB Ethernet device. These use a fair amount of power, and with only one OTG microUSB connector on the RPi Zero, you probably would have to get a powered hub (and power supply for the hub). Each RPi Zero in the cluster would also need a Class 10 SD card of (at least) 4GB, which would add a few dollars to each single-core node of your supercomputer. By the time you have purchased your eight nodes, hubs (and power supplies), SD cards, and networking cards, you are probably looking at $30 per node.

You might argue that the eight RPi Zeros give you a lot of memory, but that memory comes in half-gigabyte "clumps," and each clump has to load a duplicate of the operating system, networking software, and application code, leaving very little room for data. And, the overhead of message passing uses a lot of CPU, so the RPi Zero cluster will probably not be very efficient.

Now you have a fairly inefficient "supercomputer" that with its hubs, multiple power supplies, cables holding Ethernet controllers (did I mention the 16-port Ethernet switch you need to connect them?) probably costs around a couple hundred dollars to build.

On the other hand, you can purchase an eight-core, 64-bit ARM system with two GB of RAM and wireless 802.11n built-in, running at 1.2 GHz for $99 [1]. The efficiency of OpenMP or OpenCL to control your parallel threads on a shared-memory model for your application instead of OpenMPI across networking interfaces will be breathtaking (this is not a slight on OpenMPI; every tool has its place).

"I need a Zero!" I can hear the cries coming now. Of course you do, and you will get it.

Almost 50 years ago, the first portable electronic calculators were produced. Displaying through Nixie tubes, they could add, subtract, multiply, and divide, and they cost about $400. I never bought one of these calculators because I had more powerful computers to do my calculations at school and work. These computers were not portable, but they were much more powerful than the calculators of the day. Eventually, the more portable calculators became so inexpensive that they were given away as prizes for opening accounts at banks and, later still, given away at trade shows. I never bought a "calculator" in my life.

The miracle of the Raspberry Pi Zero is not that you need a Raspberry Pi Zero, but that you will soon be able buy as many Raspberry Pi Zeros as you want for $5 a piece.