3 ms·

It has earned its title as "one of the two hardest problems in computer science": cache invalidation, naming things, and off-by-one errors.

jdthedisciple 4y ago
the multiple layers of irony in this one just always amaze me
- mklepaczewski 4y ago
  You may also like this one (from https://twitter.com/mathiasverraes/status/632260618599403520 https://twitter.com/mathiasverraes/status/632260618599403520): There are only two hard problems in distributed systems: 2. Exactly-once delivery 1. Guaranteed order of messages 2. Exactly-once delivery
moring 4y ago
IMHO off-by-one errors only deserve to be there for the irony. In reality, they are orders of magnitude easier then the other two.
- javajosh 4y ago
  Yes, off-by-one is easier to fix, but far more common. Hence if suffering is the product of frequency and difficulty, then off-by-one suffering (S=FD+1) is the same order as cache invalidation (S=FD).
  - filbo 4y ago
- stavros 4y ago
  That is, indeed, the joke.
  - Dylan16807 4y ago
    No? They're talking about something mostly orthogonal to the joke, which is whether it actually deserves to be in the list. It's the difference between "here's three very hard things, let's make a joke with them" and "here's two very hard things, but we can make a joke if we shoehorn in a less-hard thing".
    - stavros 4y ago
      But that is why it's there, as a joke, not as an actual hard thing.
      - Dylan16807 4y ago
        Are you sure? I think it is intended as an actually hard problem and is forming a joke. I've never interpreted "oh it's not actually hard" as being part of the joke.
        moring 4y ago
        I always assumed that at the time it was a relatively harder problem, with lower-level languages that are mostly array-focused, no real built-in containers and no for-each support. This was cured with better programming languages. On the other hand, cache invalidation and naming things are problems that grow harder and harder when systems get more complex, which they obviously did.
- willis936 4y ago
  Perhaps the category was improperly named.
ricardo81 4y ago
I like how your answer wasn't just one of the list. I was almost not going to post this reply to illustrate your point.

jdthedisciple 4y ago

the multiple layers of irony in this one just always amaze me

mklepaczewski 4y ago
You may also like this one (from https://twitter.com/mathiasverraes/status/632260618599403520 https://twitter.com/mathiasverraes/status/632260618599403520): There are only two hard problems in distributed systems: 2. Exactly-once delivery 1. Guaranteed order of messages 2. Exactly-once delivery

moring 4y ago

IMHO off-by-one errors only deserve to be there for the irony. In reality, they are orders of magnitude easier then the other two.

javajosh 4y ago
Yes, off-by-one is easier to fix, but far more common. Hence if suffering is the product of frequency and difficulty, then off-by-one suffering (S=FD+1) is the same order as cache invalidation (S=FD).
- filbo 4y ago
stavros 4y ago
That is, indeed, the joke.
- Dylan16807 4y ago
  No? They're talking about something mostly orthogonal to the joke, which is whether it actually deserves to be in the list. It's the difference between "here's three very hard things, let's make a joke with them" and "here's two very hard things, but we can make a joke if we shoehorn in a less-hard thing".
  - stavros 4y ago
    But that is why it's there, as a joke, not as an actual hard thing.
    - Dylan16807 4y ago
      Are you sure? I think it is intended as an actually hard problem and is forming a joke. I've never interpreted "oh it's not actually hard" as being part of the joke.
      - moring 4y ago
        I always assumed that at the time it was a relatively harder problem, with lower-level languages that are mostly array-focused, no real built-in containers and no for-each support. This was cured with better programming languages. On the other hand, cache invalidation and naming things are problems that grow harder and harder when systems get more complex, which they obviously did.
willis936 4y ago
Perhaps the category was improperly named.

ricardo81 4y ago

I like how your answer wasn't just one of the list. I was almost not going to post this reply to illustrate your point.