[HN Gopher] All clocks are 30 seconds late
___________________________________________________________________
All clocks are 30 seconds late
Author : fouronnes3
Score : 197 points
Date : 2025-01-06 17:40 UTC (5 hours ago)
(HTM) web link (victorpoughon.fr)
(TXT) w3m dump (victorpoughon.fr)
| idunnoman1222 wrote:
| Except analog clocks, remember those?
| jgrahamc wrote:
| Yes. My Casio on my wrist has a minute hand that creeps slowly
| from minute to minute.
| Bootvis wrote:
| The article does have a picture of an analog clock (The Big
| Ben) I think. The problem is not analog but showing seconds or
| not.
| cortesoft wrote:
| Depends if the analog clock "ticks" on the minute or if it
| does a constant movement during the minute.
| serviceberry wrote:
| Not really. A mechanical analog clock will typically have
| smooth motion, so 30 seconds into a minute, the minute hand
| will be halfway between two values.
|
| Most quartz watches with analog displays work the same. I
| don't know about Big Ben, but it's possible the author is
| wrong about that example.
| stvswn wrote:
| I don't think so, because the sweeping motion of minute hand
| is effectively continuous rather than discrete, so there's no
| truncation. At 4:53:30 the minute hand will be correctly in
| between 4:53 and 4:54, if one (like the author) cares about
| such precision.
| tialaramex wrote:
| Technically Big Ben is the bell, the clock has typically been
| referred to as the Great Clock because that's sufficient
| explanation of what you meant. The tower, which like the
| clock is often referred to just as "Big Ben" colloquially,
| was formally named "Elizabeth Tower" in honour of the late
| Queen some years ago.
| fortran77 wrote:
| On a larger analog clock, you can clearly see the minute hand
| progress from one minute mark to another.
| geocar wrote:
| It doesn't have to be large: My wristwatch does it.
| scarby2 wrote:
| i don't think the above comment is saying it has to be large,
| just that it's less obvious on a smaller clock
| frenchie4111 wrote:
| What about ages?
| scarby2 wrote:
| i vote we move to the korean system where everyone gets a year
| older on January 1st
| grodriguez100 wrote:
| That was a fun one but I think they changed it already.
|
| https://www.bbc.com/news/world-asia-66028606.amp
| epcoa wrote:
| The fallacy is it's a leap from logic to go from "average error
| is x" is the same as "is x late". Seeing the exact transition is
| often if not more useful than minimizing average displayed error.
| hartator wrote:
| Interesting take!
|
| Both of your pic examples are wrong though. That digital clock
| does show seconds and the London clock has its minute hand in
| between minute mark - showing progres between minute mark if you
| look closely. This is the same for all analogue clocks.
| crgk wrote:
| I'm ready for the rebuttal post: "different clocks have
| different approaches to conveying information about seconds
| within a minute" which uses the same photos as examples.
| fouronnes3 wrote:
| No my digital clock doesn't show seconds. As for the london
| one, I was actually wondering about that! I know it depends,
| because some analog clocks work like digital one and snap to
| the next minute by discrete increments.
| kevin_thibedeau wrote:
| All escapement driven clocks are discrete.
| michaelcampbell wrote:
| Pedantically, only above second granularities. They're
| continuous between second hand sweep movements at subsecond
| ones, no? I mean, there's no point on the watch that the
| second hand doesn't "hit" at some point, however small.
|
| Or am I wrong that "intermittent, jerky, continuity is
| still continuity"?
| DiggyJohnson wrote:
| Well it depends on the interval. Taken to the limit, this
| would be a very nerdy way to rediscover calculus.
| donkers wrote:
| This is true unless you look at something like a Seiko
| Spring Drive, which has a completely smooth second hand
| sweep, although it's not entirely mechanical (and maybe
| only watch nerds care about this)
|
| https://www.hodinkee.com/articles/does-spring-drive-have-
| an-...
| undersuit wrote:
| Analog Clock movements with second hands! The seconds hand is
| rarely smooth, we want the tick, but the minute hand and hour
| hands are smooth.
| TeMPOraL wrote:
| Except those of us (like my SO) who are bothered by the
| ticking sound at the edge of audibility, and prefer smooth
| seconds motion.
| timw4mail wrote:
| Unless it's an old AC-motor clock
| necovek wrote:
| Most analog (really, with a geared mechanism) clocks do not
| "snap" on exact minutes but slowly drive toward them (because
| that's simpler and thus cheaper).
| tavavex wrote:
| Not all analogue clocks smoothly move the minute hand to show
| progress in the current minute. Many of them tick over,
| truncating the information to the minute like what digital
| clocks do.
| michaelcampbell wrote:
| Maybe; I think of analog clocks as ones with an analog,
| continuous mechanism. As such they happen to use a sweep hand
| display.
|
| Quartz and the like CAN also use non-digital displays, but I
| wouldn't consider them analog timekeepers.
| lupire wrote:
| Quartz is an analog mechanism like a pendulum. It doesn't
| stop at each cycle.
| BenjiWiebe wrote:
| Quartz is an analog mechanism, but AFAIK it's always
| read/used digitally.
| perryizgr8 wrote:
| No. Most analog wrist watches use a quartz mechanism.
| itishappy wrote:
| The output of the quartz oscillator is a high frequency
| electrical signal which is read by a digital frequency
| divider then fed back into a motor.
|
| > The data line output from such a quartz resonator goes
| high and low 32768 times a second. This is fed into a
| flip-flop (which is essentially two transistors with a
| bit of cross-connection) which changes from low to high,
| or vice versa, whenever the line from the crystal goes
| from high to low. The output from that is fed into a
| second flip-flop, and so on through a chain of 15 flip-
| flops, each of which acts as an effective power of 2
| frequency divider by dividing the frequency of the input
| signal by 2. The result is a 15-bit binary digital
| counter driven by the frequency that will overflow once
| per second, creating a digital pulse once per second.
|
| https://en.wikipedia.org/wiki/Quartz_clock
| zokier wrote:
| Almost every clock based on mechanical escapement stops
| hands on each beat. That is where the ticking noise of
| classic mechanical movement comes from. For quartz
| clocks, smooth sweeping hands is a premium feature and
| I'm not sure are even those truly continuous motion or
| just higher frequency.
| BenjiWiebe wrote:
| I have never seen a round clock with hands that ticks over a
| minute! And I look at clocks. Most that have second hands
| tick over seconds, though.
|
| Where do you live?
| aidenn0 wrote:
| In movies when the villain has placed the hero in the
| mechanism of a clock-tower, the minute hand seems to always
| tick over a minute. I don't recall ever seeing it in real-
| life, but I don't look at clocks in clock-towers that
| often.
| perryizgr8 wrote:
| I see these clocks often in railway stations (I live in
| India). There is no seconds hand. The minute and hour hands
| move in clicks, not smoothly like most clocks.
| roywiggins wrote:
| Vaguely related: I don't think people are being taught how to
| read analog clock faces nearly as much anymore, and apparently
| phrases like "quarter past ten" are becoming, so to speak,
| anachronisms.
| marpstar wrote:
| a "quarter" means 1/4th -- it's a "quarter" turn of rotation
| on a physical clock, but 60/4 is always 15.
|
| or were you making the distinction between "quarter past" and
| "quarter after", because I'd agree that the former is a lot
| less common.
| roywiggins wrote:
| I'm not sure, but either way, "it's a quarter past 6" has
| gotten me blank stares.
| dmd wrote:
| Public schools here in suburban Boston MA still teach analog
| first.
| ta1243 wrote:
| Don't kids know how to tell the time before they go to
| school?
| dmd wrote:
| Mine did. Most don't.
| aidenn0 wrote:
| So do the public schools here, and we have 3 analog clocks
| in my house, but 3/4 of my children cannot read an analog
| clock, and 2/4 of them do not understand me when I say
| "quarter past" or "quarter to" no matter how many times I
| explain it.
| doubled112 wrote:
| Also vaguely related, I've come to realize some people find
| metric measurements easier than feet and inches.
|
| I find the fractions simpler. Need a half of that half? Just
| double the denominator.
|
| My wife would seemingly rather keep counting .1 centimeters.
|
| The same applies with clocks. It's easier for me to rough out
| how long I have if I just chop the face into fractions vs
| mental arithmetic, as brutal as that sounds. What do you mean
| this guy can't divide 30 in half?
| BlueTemplar wrote:
| Romans were using both : "metric/decimal" for numbers, but
| "imperial/dozenal" for fractions :
|
| https://en.m.wikipedia.org/wiki/Roman_abacus
|
| (Base 12x5=60 was of course used by their Babylonian
| predecessors.)
| lupire wrote:
| Technology Connections did it:
|
| https://m.youtube.com/watch?v=NeopkvAP-ag
|
| Bonus on analog vs digital mechanism in flip clocks:
|
| https://m.youtube.com/watch?v=ZArBfxaPzD8
| Suppafly wrote:
| The only one that I know of as being an anachronism is saying
| "quarter of" or similar. At one point people decided that
| 'of' meant 'to' and after a while we forgot that because it
| was stupid. People still say quarter past though.
| aidenn0 wrote:
| My teenage daughter needs me to explain it to her every
| time I say either "quarter past" or "quarter to"
| Suppafly wrote:
| past and to are pretty self explanatory if you know
| English at all.
| dboreham wrote:
| This is regional. US never used quarters afaik.
| scrozier wrote:
| Oh yes, I grew saying "quarter past four." Probably don't
| anymore, but it was definitely in the vernacular in the US
| in years past.
| Gormo wrote:
| What do you mean? People in the US routinely use "quarter
| after" and "quarter to" when telling time.
| JohnBooty wrote:
| I've only ever lived in NE USA, but I have traveled, and I
| definitely don't think it's regional.
|
| Generational though, sure.
| Gormo wrote:
| But 15 minutes is a quarter of an hour regardless of whether
| you are using an analog or a digital clock to read the time.
| PeterCorless wrote:
| Yes. Though analog second hands often "tick" the seconds. (Some
| move the second hand smoothly.)
| adamanonymous wrote:
| This is why analog clocks are superior to digital
| RIMR wrote:
| >That digital clock does show seconds
|
| It most certainly does not.
|
| I see HH:MM, temperature in Celsius, humidity in percent, alarm
| status, alarm time, day of the week, and DD/MM. None of those
| are seconds. It is a truncating digital clock that rounds down.
|
| >the London clock has its minute hand in between minute mark -
| showing progres between minute mark if you look closely.
|
| "If you look closely" isn't really how analog clocks work in
| practice. Without a second hand, the limits of human vision
| prevent us from fully calculating the time between minutes, as
| each second only represents a 0.1deg change in angle of the
| minute hand, and most mechanical analog clocks aren't designed
| for the minute hand to move perfectly linearly between minutes.
| nelsondev wrote:
| Perhaps we could retitle the link, as it stands a bit click-
| baity.
|
| Perhaps, average error of clocks is 30 seconds higher because
| minutes use .floor() nor .round()
| tommi wrote:
| The whole post feels like nonsense.
| taco_emoji wrote:
| It is. It's just taking something obvious and
| recontextualizing in language that sounds like a Mysterious
| Conspiracy when it's really just a banal truth we all take
| for granted because all the other options make less sense.
| Like using tau over pi in geometry.
| benatkin wrote:
| I like to think of it as TRUNC
| zazaulola wrote:
| For positive numbers, both the FLOOR() and TRUNC() functions
| return the same values
| benatkin wrote:
| And for negative numbers it's CEIL()!
|
| And in SQL Server, ROUND() with a nonzero number for the
| third parameter for truncate, and CELING() for ceiling.
| add-sub-mul-div wrote:
| This hall monitor mentality in every comments section is more
| annoying than titles ever are.
| ainiriand wrote:
| Somehow I do not think that the Big Ben transitions the minute`s
| hand by using the floor function from Python.
| SideburnsOfDoom wrote:
| But neither is it continuous. It ticks. The mechanism might be
| made from iron, but a part of it is not unlike a floor
| function.
|
| https://en.wikipedia.org/wiki/Escapement
| philip1209 wrote:
| Perhaps, to be more precise, "How should clocks without a second-
| hand round?"
| qianli_cs wrote:
| I think truncating down allows us to procrastinate a little more
| :)
| jakebasile wrote:
| The article is claiming that clocks that only show time truncated
| to a minute are off by an average of 30 seconds, which just isn't
| true in practice. When I say or hear 11:30, I assume it can be
| within 11:30:00 and 11:30:59. Humans rarely need accuracy to the
| second beyond this, so clocks intended to be used by humans
| truncate to the minute without causing problems. To say they are
| "late" is a real leap.
|
| I mean, you can reduce this to absurdity too. A clock truncating
| to seconds is off by an average of 500 milliseconds! The problem
| is no one cares in day to day usage which is what human readable
| clocks are made for.
| necovek wrote:
| > When I say or hear 11:30, I assume it can be within 11:30:00
| and 11:30:59.
|
| And if you cared about seconds-precision, you would assume
| 11:30:30, and thus your error would average the same 15s.
|
| The difference is that when you observe a minute change, you
| know that's exactly at zero seconds (instead of 30 -- or 31 if
| you apply the same rounding rule to seconds).
|
| It is fair to ask a question if rounding would be more useful
| (nope), but the entire article is incoherent and speaks mostly
| of the author's confusion.
| glitchc wrote:
| So this is not about _all_ clocks but more about _all clocks that
| do not show seconds_. In that case, sure.
| Someone wrote:
| FTA: All the above clocks have one thing in common: they don't
| show seconds
|
| One of those clocks is Big Ben in London.
| http://www.bigben.freeservers.com/clocmech.html:
|
| _"Drive to the hands is by an oblique shaft which drives bevel
| gears positioned centrally on a gantry above the clock, with four
| shafts running out to each dial. Because there is no remontoire
| the hands on the dials advance by 2 seconds every two seconds,
| i.e. at every swing of the pendulum"_
|
| = if you look close enough, you can read the time at intervals of
| two seconds.
| keskival wrote:
| It's not really about flooring or rounding, but whether one
| thinks of time indices as ranges or moments.
|
| Days, as the author points out, are though of with "flooring",
| but more accurately it could be said that a date is thought of as
| a range between the times belonging to the date.
|
| Minutes one can consider as ranges or time indices. There the
| error comes, in switching the interpretation of a start of a
| duration to an actual estimate of a point of time index.
| ASalazarMX wrote:
| A minute is an insignificant period for most daily tasks, so
| the convention "show me when the minute changes" is simple and
| pragmatic. If your task needs precise count of seconds, you get
| a clock that shows when the second changes, and now you are
| half a second late on average.
|
| You can keep playing with increasingly smaller time units until
| you conclude, like Zeno's arrow paradox, that you're always
| infinitely late.
| derbOac wrote:
| I think that's about right.
|
| Another way of thinking about this is that the author is
| confusing time as measurement (how much time) with time as rule
| (what time is it). If you wanted to measure the duration as a
| difference in clock times, yes, there would be a certain amount
| of measurement error incurred by the way clocks are displayed.
| But if you want to know the time, in the sense of whether a
| certain time has been reached, or a certain graduation has been
| crossed, it doesn't make sense to round to the nearest minute.
|
| The question of "how much is this clock off?" is only
| meaningful with reference to a certain use or interpretation of
| the numbers being displayed. If you say it's "8:56" people know
| it could be anything up to but not including 8:57, but greater
| than or equal to 8:56. The number means a threshold in time,
| not a quantity.
| benatkin wrote:
| I can imagine a 20 and a half year old in the US arguing this
| logic when fighting an underage drinking charge.
| chatmasta wrote:
| Drivers licenses would be more accurate if they showed place of
| birth. Maybe the kid grows up to move to an eastern timezone
| and is accused of drinking a few hours early!
| hammock wrote:
| I use a certain trick a lot when cooking, or timing anything with
| precision of a several minutes:
|
| 0) Suppose I am steaming vegetables for 8 minutes
|
| 1) I will check what time I started them (say 5:30)
|
| 2) I will forget the number of seconds that were on the clock
| when I started
|
| 3) I will pull the vegetables off at 5:38:30
| valbaca wrote:
| I think a good part of this comes from how we often mention time:
| "It's half past two" is interpreted to mean: "it's _at least_
| half past two "
|
| If we round seconds, why not microseconds/etc?
|
| Ticking clocks let us know what time it is "at least" and uses
| the minutes :00 as the "barrier" Shifting that to :30 only causes
| more confusion IMO
| rantallion wrote:
| > "It's half past two" is interpreted to mean: "it's at least
| half past two"
|
| I think most people would have no issue calling 14:28 "half
| past two". There's no "at least" to it, just an approximation.
| timerol wrote:
| If it was 2:27 and I asked you the time, I would be much
| happier with "half past two" than "quarter past two"
| ahazred8ta wrote:
| The Hunt for Red October gave us "He always goes to starboard
| in the bottom half of the hour."
| jtbayly wrote:
| I can get behind this idea, however, this sentence is wrong:
|
| "If clocks rounded to the nearest minute instead of truncating,
| the average error would be 0."
|
| The negative and the positive error don't cancel each other out.
| They are both error. The absolute value needs to be used.
| fouronnes3 wrote:
| That's a very fair nitpick, but even with a more rigorous error
| function the point still stands, I think.
| jtbayly wrote:
| Agreed. There _will_ be less error, just not zero. I thought
| it was a silly error that detracted from the point, rather
| than defeated the point.
| Straw wrote:
| The average error is in fact 0! The average absolute error is
| reduced but not 0.
| jtbayly wrote:
| That may technically be correct, but it is incorrect in the
| real world. I submit that error is error in the real world.
| Mathematics can go jump off a cliff unless it wants to be
| helpful. :)
| roywiggins wrote:
| Zero average error conveys something important though: the
| error that there is, isn't biased positive or negative.
| pkilgore wrote:
| That's language failing us, not maths :-)
| noqc wrote:
| What are you talking about? Error is a metric.
| lupire wrote:
| It depends on the application. Are you summing times (as with a
| pay clock at a job), or are you paying for error in both
| directions for some reason?
| jjslocum3 wrote:
| Plenty of nitpicking here, for me this piece was a fun and clever
| thought-ride.
| TimTheTinker wrote:
| This blog post is a really good argument. The kicker for me was
| that we all generally switch to rounding when asked for the hour
| (without minutes) but don't round when asked for the minute
| (without seconds). That's an inconsistency for which there
| doesn't seem to be a good reason.
|
| However, this inconsistency only exists orally. When a device
| displays the time, it never rounds. Changing the convention would
| probably be very confusing for a lot of people, at least
| initially.
|
| For now, I'm convinced that when communicating the minute orally,
| I should round to the nearest minute, just like I do with hours.
| necovek wrote:
| Verbally, IME, people mostly round to quarters of an hour
| (exact hour, quarter past, half past, quarter to).
|
| I've never heard anyone say it's 4pm when it was 3.31pm.
| Ukv wrote:
| I don't think this applies to Elizabeth Tower/Big Ben, as it's an
| analogue clock and, from footage I can find[0], its minute hand
| appears to move continuously opposed to in steps. (or at least,
| not in full-minute steps)
|
| Also, I believe it's wrong to say "the average error would be 0"
| if rounding to nearest minute. The average offset would be 0, but
| the average error would be 15, to my understanding.
|
| [0]: https://www.youtube.com/watch?v=eUP3DsiqkzA
| fouronnes3 wrote:
| That's a good point, I was actually wondering about that. I've
| seen a lot of jumping analog clocks so I incorrectly assumed
| Big Ben was the same. I should have checked :)
| tim333 wrote:
| The jumping ones are mostly electrically activated. Big Ben
| from 1854 is gloriously mechanical - some of the mechanism:
| https://www.youtube.com/watch?v=G-WSzdAF8b8 pendulum
| https://youtu.be/U8gkgWoFBAw guy who winds it
| https://youtu.be/dMT-OOrLBik
| taco_emoji wrote:
| > Hours: That's when mentally, I switch to rounding! At 15:48 I
| definitely feel like it's pretty much 16:00.
|
| Disagree. I would never round to a full hour, only to nearest 5
| minutes.
|
| As far as minutes, for clocks that show discrete minutes, it'd be
| weird to see the minute-hand snap to the next number and think
| "oh, it's actually 29 seconds before that number". Seeing the
| snap motion means you're at :00 seconds.
|
| Besides, for a clock that doesn't show seconds, it really doesn't
| matter. If you need more precision, you just use a timepiece with
| the extra precision.
| CharlesW wrote:
| By this logic, the author must also tell people it's "2024" until
| July 3, and that we're still in the 20th Century until 2051.
| monktastic1 wrote:
| No, if you read the article, you'll see that he addresses this
| point.
| lupire wrote:
| It's addressed by "I'm not so sure."
| gkfasdfasdf wrote:
| I don't think rounding clocks would be any more useful in the
| scenario about mentally calculating how many minutes until the
| meeting at noon, because a rounding clock would show noon 30
| seconds earlier, so the average difference between 11:55 and noon
| in a rounded clock vs a floor clock is still 4.5 minutes.
| encom wrote:
| >Please someone tell me I'm not crazy
|
| No, it's probably just autism.
| jsnell wrote:
| > This is especially apparent when you're trying to calculate
| "how much time until my next meeting?", and your next meeting is
| at noon. If it's 11:55, you would usually mentally subtract and
| conclude: the meeting is in 5 minutes. That's how I always do it
| myself anyway! But the most probable estimate given the available
| information is actually 4'30"!
|
| Ok. But what does it mean for a meeting to start at 12:00 when
| people don't have clocks that will accurately show 12:00? They'll
| only know when the time is 11:59:30 or 12:00:30, anything between
| is just going to be a guess. So it seems to me that the start
| times would just align to the half-minute offsets instead, and
| we'd be back exactly where we started but with more complexity.
| xattt wrote:
| All broadcast studios are equipped with master clocks that show
| seconds to deal with this ambiguity.
|
| You can look at your own watch and anticipate when program
| transitions in radio or TV are supposed to take place (usually
| the minute and 30 second marks). Also, get a sense when a host
| is filling time to get to the transition.
| dylan604 wrote:
| I've done a lot of work with hosts on various shows. One guy
| stood out more than others on being so natural on the
| vamp/stretch to fill the time. Starting at 5mins, we give one
| minute signals. Not once did it ever sound unnatural in
| trying to rush or filled with ums, uhs, or ahs. Others
| struggled with the rushing being most noticeable.
| bena wrote:
| Exactly, this article can be summed up on one sentence: "Look
| at me, I'm so clever"
| sigmar wrote:
| This is a good point. There's tons of times when I'm watching a
| clock to watch for a precise moment (like buying concert
| tickets, limited edition merchandise, stock market opening).
| Losing the ability to see when a 12:00:00 happens would be
| annoying
| brnt wrote:
| The technically correct thing to do would be to educate on
| precision, perhaps even display it, such that people know that
| 12:00 means a time between 11:59 and 12:01, not 12:00.000.
| timerol wrote:
| The point is that we use 12:00 to note a time between
| 12:00:00.0 (inclusive) and 12:01:00.0 (exclusive). Saying
| that 12:00 is a time between 11:59 and 12:01 implies that the
| range of error is twice as big as it actually is.
|
| How long between 12:01:00.0 and 12:00 (as read on a clock)?
| Between 0 and 60 seconds.
|
| How long between 11:59:00.0 and 12:00 (as read on a clock)?
| Between 60 and 120 seconds.
| brnt wrote:
| What I am saying is that that use is incorrect as well.
| There is only one way to understand numbers, and that is
| scientifically. I.e. significant digit.
| lxgr wrote:
| Good luck educating people on why they should change lifelong
| habits that actually even make more sense most of the time
| too.
| croes wrote:
| > If it's 11:55, you would usually mentally subtract and
| conclude: the meeting is in 5 minutes.
|
| Even that part is wrong. I guess I'm not the only one who knows
| and thinks it's less than 5 minutes.
| FartyMcFarter wrote:
| > If it's 11:55, you would usually mentally subtract and
| conclude: the meeting is in 5 minutes. That's how I always do
| it myself anyway! But the most probable estimate given the
| available information is actually 4'30"!
|
| The way I like to think about it is "the meeting is in less
| than 5 minutes". Which is always correct since my reaction time
| to seeing the clock switching to 11:55 is greater than zero.
|
| It could even be less than 4 minutes if it has already switched
| to 11:56 and I haven't had time to react to that change, but
| that's OK - my assessment that I have less than 5 minutes to
| get to the meeting is still correct.
| timerol wrote:
| If you care about starting a meeting to within better precision
| than a minute, use a clock that shows seconds. If I want to
| start a meeting at noon, I don't block off the minute display
| of my clock and wait for the 11 -> 12 transition to start the
| meeting.
| tavavex wrote:
| > It would be weird if we rounded for years, months and days,
| that's for sure. I think most people think of those scales as
| intervals. In other words, July is a period of time, with a start
| and an end. So are years, centuries, seasons. We are inside of it
| or outside.
|
| I feel like my sense of time is different from the author's.
| While it can be useful to round the current hour/minute on some
| occasions, the information about which exact segment of the
| day/hour you're in can also be very useful. I can certainly tell
| that I ask the question of "when exactly is it going to be
| 12:00?" far more often than "how many seconds have statistically
| likely elapsed in the current minute?"
|
| The biggest issue for me is that the precise moment of when one
| minute/hour transitions into the next is important for people.
| Like, when coordinating an event or meeting, would you prefer it
| if your clock indicated the precise moment when 12:59:59 becomes
| 13:00:00 and told you to start the meeting, or would it be better
| if the clock instead told you that it was "13ish" and you'd have
| to wait out ~30 seconds by counting in your head?
|
| This also causes a jarring discontinuity - now clocks with a
| ticking hour hand appear to run 30 seconds late than clocks
| without, turning on the digital clock setting to show seconds
| offsets it, and so on. Some people celebrate New Year's or
| occasions that happen at a specific time 30 seconds early because
| they no longer have a strong reference point.
| 1832 wrote:
| I agree this is an interesting take and fun to think about. But
| if clocks rounded to the nearest minute instead of truncating,
| the average error would be still be greater than 0 I think, and
| not 0, as the author claims. Assuming a sufficiently large number
| of measurements taken at random times, I think the average error
| would be 15 seconds.
| timerol wrote:
| The author meant "average error" in the systematic error sense,
| not the standard error sense. The minute display would be well
| calibrated, not precise to less than a minute.
| daggersandscars wrote:
| While most analog clocks' minute hands sweep from minute to
| minute, jumping minute clocks have the issue the article brings
| up.
|
| Depending on when / where you went to school, you may have had
| analog jumping minute clocks. The ones we had at one school would
| "give away" when the minute would change because the minute hand
| would move slightly counterclockwise before changing to the next
| minute.[0]
|
| Per reddit, some Swiss Railway clocks had jumping minutes, but I
| have not seen one in person. [1]
|
| Another school I attended had sweep second and minute hands, but
| would hold the clock at 59 seconds until it matched the master
| clock. Depending on the particular clock and how well it was
| maintained, these could be 5 - 10 seconds off. Seems like nothing
| as an adult, but as a kid wanting to go home, it seemed like an
| eternity, especially on the last day of class for the semester.
|
| [0] This video shows how clocks worked at my school:
| https://www.youtube.com/watch?v=jpU_lG_TPP4
|
| [1]
| https://www.reddit.com/r/clocks/comments/10714a1/hard_time_f...
| mglz wrote:
| Ha?! A clock shows the period of time we are currently in. A
| clock only showing hours would for example indicate that we are
| in the 14th hour of the day, for the entire duration of that
| hour. That is not an error. Similarly, a hh:mm clock will show
| the hour and minute we are currently in for the duration of that
| minute.
|
| No clock can display the exact current moment of time. That would
| require infinite digits, and even then those will be late, since
| lightspeed will ensure you recieve the femtoseconds and below
| really late.
| cess11 wrote:
| What time it is, is just made up, it's something we can decide
| freely through social power, as evidenced by timezones and
| daylight savings and leap seconds.
|
| Commonly the resolution is something like minutes or a few of
| them, that's the margin we'll typically accept for starting
| meetings or precision in public transport like buses.
|
| The utility of femtoseconds in deciding what time it is seems
| pretty slim.
| v4vvdq wrote:
| An analog clock does show the exact current moment of time (if
| the hands move in a linear motion and don't jump).
| johnea wrote:
| Another perfect example of wasted disk space and bandwidth on the
| internet 8-/
|
| Not to mention a waste of the one truely nonrenewable resource,
| our time...
| HarHarVeryFunny wrote:
| I'd be very surprised if a smartphone, syncing itself to a
| reference, is ignoring seconds. Why would it?
|
| To me, if a clock that doesn't display seconds is displaying
| 09:30, then I assume the time could be anywhere between 09:30:00
| and 09:30:59.
|
| Presumably when setting the time on a device that doesn't display
| seconds, the seconds are being reset to 0 (i.e. setting time to
| 09:30 is setting it to 09:30:00), so if someone really cares
| about sub-minute accuracy they can take this into account.
| bena wrote:
| All this does is move when the issue he claims exists presents
| itself.
|
| If we flip the minute display at the 30, then the same problem
| occurs because if you start timing from the 20, the minute will
| change in ten seconds.
|
| This article is just kind of stupid masquerading as smart.
| ajb wrote:
| "It's just a convention"
|
| This is correct. In fact, in one sense our clocks could be argued
| to be minutes out, on average: originally time was measured by
| the sun. But by the sun, the earth doesn't rotate in exactly the
| same time each day during the year. So a clock assuming each day
| is the same length (like they all do) accumulates an error with
| respect to sun time of more than 16 minutes,and then loses it
| again, in a cycle.
|
| But we just collectively decided that it was simpler not to
| bother with that. We changed the convention so that time is
| marked with respect to an average day length
| youainti wrote:
| Clocks are used as inputs into decisions. So this doesn't matter
| as long as the decision process accounts for it. If I see that a
| meeting starts in 5 minutes, I'm not setting a timer get there in
| 300 seconds, I'm trying to decide if I have time to fill my water
| bottle on the way or not.
|
| The post is a useful consideration to think if you are trying to
| do precise tasks though. See Keskival's post below about
| intervals vs moments to add some more precise ways of thinking.
| macleginn wrote:
| This is nitpicking, but the transition from "the average error of
| a truncating clock is 30 seconds" to "therefore all clocks are 30
| seconds late!" is seriously wrong. For one, the median is equal
| to the mean here, so about half of all clocks are less than 30
| seconds late, which is a clear contradiction.
| taeric wrote:
| Amusingly, one of my kids gets very frustrated with how I answer
| what time it is on most requests. Most of my answers will be of
| what the nearest relevant time is. I will never bother
| determining what the exact minute is from my watch. As I just
| can't see the value of that. Even from a digital watch, I don't
| see the need in giving a majorly different answer to the same
| question within 5 minutes or so.
| lxgr wrote:
| That's how people commonly give time in my language, I suspect
| mainly out of convenience:
|
| Quarter hour precision is possible to achieve with at most five
| syllables (and typically just two); compare that to minute-
| level precision, which usually takes at least 5 and sometimes
| as many as 10.
|
| Interestingly, spoken times also commonly use the 12 hour
| clock, while times are almost exclusively written as 23 hours.
| jpm_sd wrote:
| Time Cube redux?
|
| https://en.wikipedia.org/wiki/Time_Cube
| edgarvaldes wrote:
| If you use round instead of floor an error persists. So all
| clocks that don't show seconds are always wrong.
| Phrodo_00 wrote:
| > Is it the same for the current minute of the current hour ? I'm
| not so sure.
|
| Yes it is. Appointments start at the beginning of the minute, not
| the average. (And while changing clocks WOULD change that, I'm
| not sure it makes a lot of sense)
| necovek wrote:
| If you do care about what second it is, you can still be 59s off:
| eg. if the "rounded" clock shows 12:30, it could be 12:29:30 all
| the way to 12:30:29.
|
| The error is reduced on average if you only care how far away
| from exact minute you are, but you simultaneously _never_ know
| when it is the exact minute.
|
| The question is really about what's more generally useful: the
| offset of 30s is usually not important enough, which is why most
| clocks only show hours and minutes. Where it matters, higher
| precision is used.
|
| Some of the social constructs would be less meaningful (like New
| Year countdown) as most watches and clocks would show midnight
| 30s early.
| opan wrote:
| I enable seconds on my PC and phone clocks, and basically
| anywhere it's an option. I enjoy seeing if two messages on IRC
| were just 3 seconds apart as it will often tell you the second
| person hasn't actually read the first person's message right
| before theirs (they were probably writing their messages at the
| same time). Something not obvious if you just see the minutes.
| jordansmithnz wrote:
| While interesting this is just... wrong. Imagine a world where:
|
| - I tell people I'm 50 years old but I'm really just 49 1/2
|
| - My phone says it's Jan 7th but it's really afternoon on Jan 6th
|
| - My coworker says they're a sr engineer because they've been
| told that they'll definitely be promoted soon
|
| Rounding shouldn't be applied everywhere. Some things in life are
| supposed to use a floor function; common sense applies and most
| folks intuitively know that 1:00pm means 'between 1:00 and
| 1:01pm'.
| timerol wrote:
| TFA goes into the author's opinion around when to floor and
| when to round, and notes that "hours" is the largest interval
| where rounding feels right.
| err4nt wrote:
| A delightful read, though I disagree. Unless we were going to
| introduce half-minute units (which decreases the scale of the
| error, but makes it twice as numerous) then shifting our minute
| units by a half value doesn't seem to actually solve the problem,
| doesn't it only shift it to a slightly different location?
| seanalltogether wrote:
| You said it yourself, the data is truncated. We shouldn't be
| rounding time one way or the other, just truncating it.
| syntheticnature wrote:
| Worse yet, our calendars are all 12 hours off!
| hkon wrote:
| I show seconds in windows clock
| dsubburam wrote:
| The intended interpretation for clocks IMO is "we are now past
| this time".
|
| Like a mile marker when you are running down a jogging track.
|
| It doesn't matter if the granularity is one-day or even one-year,
| like the ball drop in Times Square on New Year's Eve.
| PeterCorless wrote:
| Anyone who has done timer or countdown-based work has to think
| the opposite. Whether that's sports or event production, rocket
| launches, or so on. You're not thinking about the time you've
| past/expended. You're thinking of the time you still have left.
| "Two minutes left in game." "We're live in 30 seconds" etc.
| lupire wrote:
| Countdown clocks run backwards, not forwards.
| timerol wrote:
| NFL delay-of-game penalties are interesting for this, because
| when the clock first shows 0 seconds, that means that the
| team still has a full second to start the play.
| hnuser123456 wrote:
| All of this is made redundant by just... knowing this is how
| clocks work.
|
| If you don't have a seconds hand/counter, you can't predict how
| many seconds are left in the current minute. If it's 11:45:01,
| it's 11:45 without seconds. If it's 11:45:59, it's still inside
| the minute-long interval known to everyone as 11:45. The clock
| can always be one second away from flipping to the next minute. I
| just mentally subtract one minute if I'm actually planning on
| being somewhere down to the fraction of a minute, and planning
| what I can do beforehand. Mentally subtracting 30 seconds is not
| any easier.
|
| I don't see this as even having some kind of gimmicky benefit...
| rkagerer wrote:
| Let me unlock your hidden precision.
|
| The writer makes an implicit assumption you just glance at the
| clock with no prior info.
|
| Where seconds count, you can watch the clock until the moment it
| ticks. At that time you have greater precision. And due to your
| own innate sense of time, that precision decays for a little
| while (maybe even 30s?) rather than instantly disappearing.
|
| I like to synchronize my clocks this way (when seconds are
| unavailable). Yes, it does mean I invest up to a minute more to
| set the time, and it's probably not worth it if you're doing so
| often (eg. area prone to power outages).
| matja wrote:
| The same technique is how computer RTCs are set/read, but to
| sub-second precision instead of minute precision, because the
| most common register standard allows only storing whole seconds
| but they keep relatively accurate time.
| GuB-42 wrote:
| Flooring makes more sense in every case, from years to
| milliseconds and more. A few reasons:
|
| You want to send a message at exactly 13:00:00, you have a
| digital clock that doesn't show seconds. What you do is that you
| watch your clock, and as soon as it goes from 12:59 to 13:00, you
| press the button. That's also how you set the time precisely by
| hand. With rounding, that would be 12:59:30, who wants to send a
| message at precisely 12:59:30 ?
|
| You have a meeting at 13:00:00, you watch the clock to see if you
| are early or late. With flooring, if you see 13:00, you know you
| are late. With rounding, you are not sure.
|
| It is common for digital clocks to have big numbers for hours and
| minutes and small numbers for seconds. If you are not interested
| in seconds, you can look quickly from afar and you have your
| usual, floored time. If you want to be precise, you look closer
| and get your seconds. Rounding the minutes would be wrong,
| because it wouldn't match the time with seconds. And you don't
| want clocks with a small display for seconds you may not even see
| to show a different time than those that don't.
|
| And if you just want to know the approximate time and don't care
| about being precise to the second, then rounding up or down
| doesn't really matter.
| TZubiri wrote:
| But if every clock was like that, then 12:59:30 would be the
| new 13:00:00
| dylan604 wrote:
| How does 12:59:30 floor to 13:00:00? Wouldn't that be the
| result of ceil?
| pkulak wrote:
| Only until the next article saying that "all clocks are 0.5
| seconds early" and we then switch to randomized rounding.
| soneil wrote:
| So if my watch shows seconds, I'd be late at 12:59:31?
| zzo38computer wrote:
| I still think that flooring would be better; however, if you
| did insist to do this rounding instead then you could use a
| different convention for numbering seconds with e.g. -30 to
| +30 instead of 0 to 60. However, I think that this is not
| worth it, and that the existing use of flooring is much
| better, although if you want such precision with timing then
| you really should display the seconds, rather than using a
| clock that does not display seconds, anyways.
| The_Colonel wrote:
| But not every clock would be like that - only those clocks
| which don't show the seconds precision would use this
| rounding.
|
| The consequence of that would be that statements like
| "fireworks start at 12 AM" would mean two different points in
| time depending on how much precision your clocks have.
| mongol wrote:
| > With flooring, if you see 13:00 you know you are late
|
| I always though that you are late from 13:01. Common these days
| with Teams meetings etc. It seems most people join during the
| minute from 13:00 to 13:01.
| flerchin wrote:
| I tell my kids this aphorism:
|
| Early is on-time. On-time is late.
| anal_reactor wrote:
| Early is on-time. On-time is late. Late is how most people
| behave.
| mikenew wrote:
| Showing up early just makes other people feel like they did
| something wrong by showing up on time.
| synecdoche wrote:
| It could be argued that people can't be made to feel
| anything, apart from pain. How people react, on the other
| hand, may be quite different.
| recursive wrote:
| True. Probably wouldn't be a very good argument though.
| flerchin wrote:
| Other people's feelings about a dimension don't change
| the dimension.
| lxgr wrote:
| In a social context, almost everything some people do
| changes how other people feel.
| mongol wrote:
| This makes a lot of sense. But where it really matters, say
| train departure times, are there rules that the doors are
| closing precisly at X seconds? Or is it arbitrary?
| flerchin wrote:
| Won't be a problem if you're there on-time.
| oniony wrote:
| In the UK the doors close 30 seconds before the
| advertised departure time.
| pests wrote:
| Depends on the power dynamic and the goals for the meeting,
| and what position you hold, no?
| flerchin wrote:
| No it does not. Time is not a dimension that changes
| depending upon power dynamic.
| lxgr wrote:
| Time isn't, but punctuality, as a social as opposed to
| physical phenomenon, most certainly is.
| pclmulqdq wrote:
| It's disrespectful to be late no matter the power
| dynamic. In some power dynamics, it's okay to be
| disrespectful, though.
| andix wrote:
| This vastly depends on culture and context.
|
| We consider it impolite, if you show up for an invitation
| at someone's home before the time you were invited for.
| Many would say it is even impolite to show up less then 5
| minutes late, and consider being 10-15 minutes late the
| best, and up to 30-45 minutes acceptable.
|
| For a business appointment or doctor's appointment, where
| there is an assistant that opens the door and a waiting
| area, it's expected to be early, so that you are already in
| front of the correct room when the appointment starts.
| pknomad wrote:
| I have a funny anecdote.
|
| I don't know if it's a Korean thing or my mom-specific
| thing but she had very strong opinion about being early.
| For her 15 minutes early == on time. To reinforce this
| notion, she would set the house clocks later by some
| random undetermined minutes. The clocks in her home would
| all differ slightly so you could never tell what time it
| actually was unless you looked at your phone but you'd
| know you're little bit early to things for sure. Good
| times.
| xoxxala wrote:
| We always taught our kids that if you're not five minutes
| early, you're late.
|
| One boy took it to heart and is very prompt.
|
| The other, eh, not so much. He was almost late to his own
| wedding.
| viraptor wrote:
| Because of how lots of reminders work. There isn't even a
| good way to tell Google calendar to always notify 1 minute
| before events - I had to do it through slack integration.
|
| So instead the reminder usually tells you a meeting will be
| in 15min which quite often is a useless information. Then the
| app tells you the meeting started _right now_ and you still
| need a few seconds to wrap things up and prepare.
| vel0city wrote:
| > There isn't even a good way to tell Google calendar to
| always notify 1 minute before events
|
| It's on the calendar settings. Settings for my calendars >
| Event Notifications. You can set 5 default notification
| options for all events created on that calendar.
| quesera wrote:
| Multiple notifications are a great feature. I use two:
| "10 minutes before" and "1 minute before".
|
| Because 10 minutes is just enough to wrap up something
| I'm in the middle of, and simultaneously, 10 minutes is
| well past long enough to get distracted if I'm not
| already deep in the middle of something. :)
| cbolton wrote:
| Seems like there are important cultural differences in how
| appointment times are understood. Last week I was talking to
| a friend living in the Comoros, who mentioned that for them
| 13:59 is still 13:00 for this purpose.
| lgrapenthin wrote:
| So they ignore minutes entirely and just live in hours?
| taylorbuley wrote:
| This is true across other domains! If trains are spaced exactly
| 10 minutes apart and you arrive at a random time, the expected
| waiting time is 5 minutes, for example.
| timerol wrote:
| This makes me wonder how train countdown clocks are programmed,
| and if "1 minute away" means "60-120 seconds away" or "30-90
| seconds away".
| zazaulola wrote:
| Has anyone ever wondered why in the US the week starts on Sunday,
| but in Europe and Asia it starts on Monday?
| Ylpertnodi wrote:
| I work in Europe...my week starts on a Sunday.
| lxgr wrote:
| Where in Europe is that?
| lxgr wrote:
| Yes, and it's infuriating if software draws the conclusion
| that, simply because I happen to be in region x (or even worse,
| using language x), I must also want date presentation, units of
| temperature and distance etc. to be according to customs in x.
|
| At least macOS/iOS at this point mostly allow customizing many
| of these, but some native apps and date picker widgets still
| don't respect my preferences, driving me nuts every time I have
| to schedule a reminder or meeting.
| hinkley wrote:
| This could be a good allegory for sampling intervals. I'm forever
| having to explain to people that if they are looking at data
| every 60 seconds they can take a lot longer to notice a problem
| than common sense would suggest. Your new information shows up on
| average 30 seconds late and up to 59.99999 seconds late. If
| you're trying to compare the last two samples to detect a problem
| then you're going to see it up to 2 minutes after it already
| started, since it could start 1 ms after the first sample.
| Particularly in systems where multiple actors are using periodic
| actions.
| TZubiri wrote:
| "It would be weird if we rounded for years, months and days,
| that's for sure. "
|
| We round years too, otherwise I would be in my 30s.
| jerlam wrote:
| I had a watchface on my Pebble smartwatch that only displayed
| time in five-minute intervals. This post is making me question
| whether it rounded up or not.
|
| I have to assume it did because I didn't start being late for
| everything.
|
| In case you want to see it:
| https://pebblestyle.com/watchface/BVmexStjq3j/
| Apes wrote:
| RMSE of current digital clocks rounding down is roughly 34.5
| seconds.
|
| RMSE of proposed rounding to closest is 17.5 seconds.
|
| The new method is roughly 17 seconds more accurate on average.
|
| Does this reduced error make a significant difference? Probably
| not. There are very annoying practical issues with this proposal
| though.
|
| Rounding down makes it clear what minute has already passed. If
| your clock says 3:00, you know the current time is definitely
| some point after 3:00. If something needs to happen at 3:00, and
| your clock says 3:00, it is time to start.
|
| With this proposed method, 3:00 could mean anywhere from 2:29:30
| to 3:00:30. When do you start? Do you start as soon as your clock
| says 3:00? Then you're starting 30 seconds early. Do you wait
| until your clock says 3:01? Then you're starting 30 seconds late.
|
| And how do you set a clock that uses this scheme? If I want to
| set the clock to 3:00, do I wait until 2:59:30 and then set the
| clock to 3:00?
|
| The headaches that arise from this scheme are not worth the
| trivial error reduction.
| ss64 wrote:
| Any clock which doesn't have a seconds display is probably not
| accurate to the second and is also very unlikely to have been set
| to the exact second. Those 2 factors together mean a good chance
| the time is > 30 seconds out, making the original point moot.
| codewritero wrote:
| Analog clocks mostly don't have the problem the author is
| complaining about since most minute hands move once per second
| and you can easily see (depending on your eyesight and distance
| to the clock) that the minute is partially consumed.
|
| I agree though that this is a downside to digital clocks which
| don't show seconds, though whether the best fix is to round
| instead of averaging is hard to say.
| ifdefdebug wrote:
| While you could argue that it's flooring, it feels much more like
| truncating. We have a inner representation of time that's like
| yyyymmdd-hhmmss-mmmm and we truncate it to the precision we need
| for a given task. If we need the month we truncate to yyyymm, and
| if we need hours we truncate to yyyymmdd-hh.
|
| That's quit intuitive for all kind of time precision, and the
| author's rounding solution would be somewhat counterintuitive, at
| least for me.
| lxgr wrote:
| > Basically I'm arguing that rounding for clocks would be more
| useful than flooring. This is especially apparent when you're
| trying to calculate "how much time until my next meeting?"
|
| Yet a rounding clock provides no way at all for you to know
| whether the meeting has already started or not.
|
| Not sure where I've heard this, but an idea that's been stuck in
| my head is this: We don't look at clocks to see what time it is,
| we do so to know what time it isn't yet:
|
| Have I missed the bus yet? Can I already go home? Am I late for
| this meeting? Do I still have time to cancel this cronjob? All
| questions that a rounded clock cannot precisely answer.
| layer8 wrote:
| This is why I dislike clocks without seconds.
| UniverseHacker wrote:
| I am really annoyed that it is almost universal to show only
| minutes on clocks- when so much in my life at least depends on
| knowing time to the second. Even modern digital devices like an
| iPhone make it really hard to get a seconds readout, when the
| cost of doing so should be zero.
|
| Some of the things I need precise seconds for frequently in my
| daily life: buying tickets to concerts, campsites, and kids camps
| before they sell out, checking into Southwest flights, sailboat
| race starts, and starting/joining virtual meetings I am hosting.
|
| Am I that weird that this is something I need at least once a day
| that nobody else seems to need or want?
| stackghost wrote:
| Almost nothing in my life or career to date has depended on
| knowing time to the second.
|
| Why does it matter if your noon meeting starts at 11:59 or
| 12:01?
| UniverseHacker wrote:
| It's wasteful of other peoples time to show up to a meeting
| late, and wasteful of my own to be early. I'd like to be as
| precise as practical. Meetings filled with high paid experts
| are incredibly expensive- one should get every detail right
| to save time. One little thing might not matter, but if you
| pay attention to a lot of little details in running a meeting
| efficiently- including starting as close to on time as you
| can, it saves a lot of time.
| vikingerik wrote:
| Yup. I have my clocks in the house set 30 seconds ahead to
| counteract exactly this.
| intellectualx wrote:
| All the way to the miliseconds I strongly disagree!
| pmg101 wrote:
| I definitely start saying I'm $age+1 as I approach that birthday,
| as it seems more accurate. Round, not floor.
|
| Although I have to say I've not really encountered other people
| doing this.
| inasio wrote:
| One often unappreciated and amazing thing about the GPS-on-
| cellphones era is that nowadays everyone has the exact time. Up
| to the late 20th century it wasn't trivial to have the right
| time, in fact there was a three digit phone number you could call
| to get the right time (up to the minute).
| yu3zhou4 wrote:
| I thought about it as a kid, you're definitely not crazy Victor,
| and I appreciate that you wrote this piece
| smokedetector1 wrote:
| I'm not trying to be snarky but I really don't see why this
| matters. It's just a convention. We are not robots, not
| everything has to be 100% precise.
| stackghost wrote:
| TFA fatally misunderstands what clocks actually measure. They
| measure the amount of time that has elapsed. When we say "it's
| quarter after noon" what we really mean is that 12 hours and 15
| minutes have elapsed since 00:00. The reason clocks don't round
| up is because that's simply wrong.
|
| A minute hasn't elapsed at xx:xx:36, it has only elapsed after
| :59
|
| tl;dr The author of TFA doesn't actually understand what clocks
| measure.
| o999 wrote:
| Does OP realize that people don't looks at 11:55 and think it
| means 11:55:00, but they think, it is just not 11:56 yet.
|
| Computers and smart devices syncing to NTP doesn't have 30s
| average error rate, it is the author who has 30s average error
| rate in clock-reading if he reads a digital clock and think that
| the clock tells that no seconds has passed since the last time it
| added one minute.
| layman51 wrote:
| This post is fascinating but I think it is more mundane than I
| realized. I thought everyone knew that when a cheap digital
| kitchen timer shows a time like "0 H 1 M", that actually means
| you have exactly 60 seconds or fewer for its alarm to go off.
|
| I might be wrong, but there was a Prince of Persia game (maybe
| for Game Boy?) that had the same timer behavior. It would show
| the time remaining to complete the level in minutes and would
| jump immediately from "1 minute" to 0.
|
| The iOS podcast app is more sophisticated than that. It normally
| displays how many minutes remain in the playing podcast episode.
| But what is cool is that at the 30 second boundary, it will
| decrease one minute. For example, it is at -24:30 or -24:29 that
| it will go from saying "25 minutes remaining" to "24 minutes
| remaining." Then when 30 seconds are left, it is nice enough to
| show you a countdown of the seconds.
| fouronnes3 wrote:
| Yeah, I've seen a lot of countdown UIs that incorrectly start
| beeping as soon as "1s" becomes "0s". In fact they should start
| beeping exaclty 1 second after that change.
|
| I'm sure this is actually an intentional design decision
| because starting to beep at 0.99 (displayed 0) feels more
| correct, even though it isn't.
| pkilgore wrote:
| Fun scissor. Seems to depend on your personal definition of
| "error", with respect to time.
| ccppurcell wrote:
| I would argue that eg 13:00 represents an interval, not a moment.
| So there is no error. But I appreciate the nerdy level of detail.
| raldi wrote:
| This is like asserting that all calendars are 12 hours late.
| gamblor956 wrote:
| This author is either an idiot or does not understand the concept
| of precision.
|
| It's very surprising that this article has engendered so much
| discussion...in support of what he is saying.
|
| 10:01:01 and 10:01:59 are both still 10:01, because a minute is a
| discrete unit of time. Rounding the minute to the next minute _is
| simply wrong._ Similarly, rounding to the next hour _is also
| wrong_ and nobody does this except apparently the author. (Note:
| 15:48 is _almost_ 1600 but _is not_ 1600.) People might round to
| the nearest five or ten minutes for convenience (i.e., when
| reading an analog clock) but that hasn 't been a thing since the
| switch to digital clocks.
| tech_ken wrote:
| One wrinkle here is the choice of signed error instead of eg.
| RMSE; absolute error metrics don't care about rounding vs.
| flooring. Since the conclusion of the analysis hinges on this
| choice of error metric, I think some justification or discussion
| of that choice adds interesting context.
|
| Signed error implies that clock-imprecision "cancels"; that being
| 20 seconds late to your meeting will be undone by being 20
| seconds early to lunch afterwards. I'm not sure if this is quite
| how people reason about 'lateness' though. Obviously in some
| applications it makes sense (ex. recording event times of some
| phenomenon of interest), but in scheduling my daily life that's
| not really how I think about things.
|
| I think RMSE is closer to how people evaluate scheduling of
| stuff; it doesn't matter if I'm late or early, both will have
| notable consequences in unique ways. The ambivalence of the RMSE
| error to rounding vs. flooring is the intuition I would put
| behind the counterargument fielded by the author:
|
| > But this is just a convention! Truncating, rounding or even
| ceiling are all valid, as long as we pick one and stick to it.
|
| I think you can also squeeze some juice out of playing with the
| error metric further. If you want a 'just-in-time' schedule (ie.
| you want to never be early to anything) then the flooring clock
| is superior to the rounding clock. If you want the opposite then
| a ceiling-ing clock would be the best choice.
|
| > Personally, I would never say that it's 10 if the clock shows
| anything past 10:30
|
| I like to floor my times to the nearest 15-minute interval (10,
| quarter-past, half-past, quarter-to), only rounding once I've
| reached ~10:55
| panda-giddiness wrote:
| > If it's 11:55, you would usually mentally subtract and
| conclude: the meeting is in 5 minutes. But the most probable
| estimate given the available information is actually 4'30"!
|
| Admittedly I'm being a bit pedantic, but this isn't true. The
| _expectation value_ might be 4 '30", but the time is as likely to
| be 4'59" as 4'30"; assuming it's 4'30" will simply minimize your
| expected error.
| geor9e wrote:
| I have about a dozen of the absolute cheapest digital clocks
| around my house, and every single one, I set it to the next
| integer minute then waited for 00s to hit the button that makes
| the : blink. So, even if every other person on earth fails to do
| this, the average is below 30s just due to me.
| iainmerrick wrote:
| The Clock app in iOS works like this in timer mode. If you start
| a timer for 10 seconds, you'll see the 10 for half a second, then
| 9 through 1 for a second each, then 0 for half a second, _then_
| it beeps. In practice it 's pretty stupid and not really useful,
| so I wish they'd fix it.
|
| There's a reason why normal countdowns work the way they do. You
| care about the exact moment it hits zero, and with rounding you
| lose that.
|
| Clocks are not 30 seconds late.
| zombiwoof wrote:
| What a waste of 30 seconds of my life reading that
| thedanbob wrote:
| If you had two rounding digital clocks, one with seconds and one
| without, they would switch to the next minute 29.5 seconds apart.
| Everyone would hate that.
| devit wrote:
| That's only the case if you interpret them as HH:MM:00. The issue
| is fixed if you interpret them as HH:MM:30 instead.
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