Wednesday, December 16, 2020

Intro to Quantum Computing (Everything I know)

Quantum computers are vastly different than digital (classical) computers. Let's start with the basics in this blog post.

1. Bits

Digital computers store information in classical bits. A bit can only be a zero or one.

Quantum computers store information in quantum bits (qubits). A qubit can be a zero or one or negative or both zero and one at the same time due to the wave nature of superposition (Yes, this is a real thing... more on this in another blog post).

2. Storage

Digital computers store bits using voltage / charge.

Quantum computers store qubits using electron spin.

3. Logic

Digital computers perform operations using logic gates governed by Boolean algebra (AND, OR, NOT, XOR, etc.).

Quantum computers perform operations using quantum logic gates (X, Y, Z, CNOT, etc) governed by linear algebra (matrix algebra).

4. Behavior

Digital computers use simulation to solve problems.

Quantum computers use imitation to solve problems.

5. Output

Digital computers are deterministic. The same input always yields the same output.

Quantum computers are probabilistic. Repetition of the same inputs gives probabilistic output.

6. Architecture 

Digital computers use a von Neumann model with a CPU, ALU, and memory to store instructions and data, all made up of transistors. Physically, bits are stored in integrated circuits (chips) at room temperature.

Quantum computers store and process data using quantum error correction to manipulate quantum objects (electrons, photons, nuclei, etc). Physically, qubits are stored in quantum objects at less than 1 Kelvin (about 0.015 Kelvin) to remove any thermal noise that could disturb them.

7. Performance

Digital computers increase performance by a factor of two for each bit added (2n).

Quantum computers increase performance exponentially for each qubit added (2ⁿ).

8. Processing

Digital computers process data in series.

Quantum computers process data in parallel.

9. Reversibility

Digital computers’ logic gates are not all reversible.

Quantum computers’ logic gates are all reversible.

There are four operations that can be performed on a single bit: NOT, Identity, Set 0, Set 1.

1. NOT: Flip zero to one or one to zero. Think: clicking on a checkbox on a web page.

2. Identity: Multiply by 1 to keep the same value (identity). Think: core memory readout, which is destructive so the bit must be saved back into memory when reading.

3. Set 0: Force a zero into memory. 

4. Set 1: Force a one into memory.

With digital computers, only the NOT and Identity are reversible gates. Quantum computers have other gates to make non-reversible operations reversible.  

Since all quantum computer operations are reversible, output from one operation can be fed back into the same circuit to recover the original input.

It seems, before 2020, researchers viewed quantum computing as primarily a scientific goal, with relatively little immediate bearing on the future commercial viability of quantum computing. However, that has quickly changed with Honeywell, Amazon, and Microsoft entering the market.

Thursday, December 3, 2020

My Cousin's COVID Story

A guest blog post from my cousin, Joe Cuiccio, who's spent a life time devoted to health and fitness. 

Now that 2020 is soon coming to an end, I wanted to take the time and share some key events which I’ve experienced during this pretty awful year. I contracted COVID-19 in mid July. My symptoms were pretty mild and I was able to return to work after my 14 day quarantine. Other than feeling pretty tired, I was more or less able to function normally. About two weeks after that, though still tired, I decided to get my first workout in after 4 weeks of inactivity. I went easy not knowing what to expect but it felt pretty good and I was relieved. For the next two weeks, I progressed, got stronger and regained some endurance. I was feeling a lot better. That is until one evening in late August. 

Soon after a late night workout, I didn’t feel right. After a bite to eat and a shower, I'd gotten into bed and noticed my heart was racing and felt unwell. I figured I’d try to get to sleep and hopefully feel better in the morning. No such luck. My heart was still racing and I felt even worse - chest and back pain, tightness, palpitations, nausea and a bit light headed. Becoming concerned, I started to wonder could I be on the verge of a heart attack? It persisted through the morning and I decided to go to emergency care. My EKG was normal but my pulse was still rapid and my blood pressure was 160/89! I was told to see my doctor ASAP. 

I get in to see my regular doc a few days later and given my symptoms and that fact that I’ve had COVID-19, he recommends I wear a 48hr Holter monitor. It reveals a series of PAC’s and PVC’s (premature heartbeats) and some arrhythmia. These results get a me a referral to a cardiologist. Long story short, after 3 long months of tests, very anxious waiting, feeling like shit, abstaining from exertion, caffeine & alcohol, I finally get my diagnosis: a cardiac MRI revealed scar tissue on my heart which is a remnant of damage caused by the coronavirus. The good news is it’s minor enough to not require any treatment at this time and is not likely to effect me in any major way. I should feel better as time goes on. I will follow up in 6 months. 

I’m sharing this because every single day, I encounter people who either think the coronavirus is a hoax, blown out of proportion, a government plot, no worse than the flu, only affects the elderly, has a 99% recovery rate and similar kinds of ignorant nonsense. As you could imagine, I’ve done a lot of research regarding COVID-19 related heart damage and it’s really scary stuff. I am beyond grateful that I was lucky enough to have dodged a serious bullet. But there are people much younger and healthier than myself who have sustained a far worse degree of damage than I. What research has found so far is that the immune system goes into overdrive to fight the virus and continues fighting long after the virus is gone. This sustained immune response can cause damage not just to the heart but other organs including the brain and nervous system. It can cause erratic spikes in blood pressure greatly increasing the risk of blood clots, stroke and heart attack. And even though not life threatening, many are experiencing chronic fatigue months after recovery preventing them from working, performing simple daily activities and greatly affecting their quality of life. The gamut of ill effects is very wide.

So, when I hear someone quote survival rates without taking into account the huge gray area of complications that can arise in recovered people, it makes me sad, angry and frustrated beyond measure. I hope that in sharing this, it may shed some light and get some of the more close-minded individuals out there to try a little harder to think outside of the box and band together to defeat this. ❤️ 

Tuesday, December 1, 2020

macOS on AWS. Finally!

One of my "server farms" (more like a server garden)
with 4 Macs and 1 GSM modem
Finally, after nearly 15 years, macOS comes to AWS. I used to maintain two server farms totaling 11 Macs, mostly Mac minis, running OS X Server with 10 static IP addresses. Configuring and replacing Mac servers was my least favorite and most expensive task.

Amazon's AWS VP for EC2 shared a fun video about how macOS on AWS came to be.