Quick Google App Engine RSA Benchmark

Update: Please read Strom's comment. He explains everything. I wasn't aware of the 15 minutes rule.

Generating a 2048-Bit RSA key with the Google APP Engine takes about 10 seconds at average. On my PC, it takes 2 seconds. I called the service six times on a clean app engine account. This resulted in 0.30 frontend machine hours being consumed. So even though I used the CPU for one minute in total, Google charges about 20 minutes (0.3 hours).

At a price of 0.08$ per hour, generating a 2048-Bit RSA key costs about half a cent. Or in other words: my cpu (intel i7, 2.8 GHz) can do about one app engine machine hour in 40 seconds. This means, doing one hour of heavy-duty calculations on my CPU would cost me about 8$ of frontend machine hours at Google.

My conclusion: Google app engine is too expensive for my intended application, unless backend machine hours differ significantly from frontend machine hours.

For reference, the core code of my servlet:

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(2048);
KeyPair kp = kpg.genKeyPair();

Use positive expressions

When striving for clear and concise articulation, in programming or in natural languages, try to express yourself with as few negations as possible. Negations leed to confusion. Our brain does not handle them well.

Example 1: It is better to ask "may I sit here?" than "is this seat taken?". Try it. The latter question will confuse some people. They might answer "no" even though the seat is taken and vice versa, especially if you mumble and all they understand is your intention to take that seat. Their brain translates the question to "should I allow the guy to take that seat?".

Example 2: if a newspaper writes "Senator Smith never smoked pot", the number of people thinking that Senator Smith smoked pot might grow because all they might remember is "senator smith" and "pot". Negative associations rarely work.

When programming, it is essential to write clear and understandable code. Avoiding the not operator helps.

• It is better to write "if x==7 then a else b" than "if x!=7 then b else a".
  
• It is also better to create a method "list.hasItems" than "list.isEmpty".
  
• It is better to have a checkbox that says "cache thumbnails" and is enabled by default than a checkbox "do not cache thumbnails" that is disabled by default (as found in the folder options of Windows).
  

You get the idea. Internalize it.