In http://research.google.com/archive/gfs-sosp2003.pdf Section 3.2 (page 6):

Suppose the client is pushing data to chunkservers S1 through S4.

Does it mean client -> S1 -> S4 or client -> S4 -> S1 ?

3 Answers 3


It means the range of S(1 through 4). In other words, it means S1, S2, S3, and S4.

  • My English is really poor...But how to express: client -> S1 -> S4?
    – Sayakiss
    Aug 5, 2013 at 9:17
  • 1
    This seems to be a feature of American English. In England and the rest of the UK, S1, S2, S3, and S4 would be expressed as S1 to S4.
    – Tristan
    Aug 5, 2013 at 10:57
  • @Tristan The OED agrees with you. Sense 5d: U.S. Up to (a date, a number, a specified item, etc.) inclusively, up to the end of, up to and including, to, until; often correlative to from.
    – user230
    Aug 5, 2013 at 11:21

This means that the data is being pushed to servers in order shown below:


Other example: Robin, could you please check for points 20 through 30?

Example above means that Robin is required to go through each of the points from 20 to 30, in that order, i.e. starting from point 20, then 21, 22, 23......and point 30 at last.

  • No, this sentence leaves order unspecified. Additionally, if you read the article, you can see that it may go in a different order depending on the relative proximity of the chunkservers.
    – user230
    Aug 5, 2013 at 10:23
  • @snailboat S1 Through S4 does not, in particular refer to an ordered sequence. But, in this case, S2 was in closest proximity to S1 (unlike S3 and S4), S3 was closest to S2 (unlike S4) and soo on. That's why the order turned out to be s1-->s2-->s3-->s4.
    – Ankit
    Aug 5, 2013 at 10:32
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    That is only one possible order, not how it turned out. The article also gives S2 -> S4 -> S3 as an example order and does not say that S3 is closest to S2. Please read the article!
    – user230
    Aug 5, 2013 at 10:39

The sentence as it stands is ambiguous.

I suspect that the writer meant that that the data is pushed to the servers with numbers between S1 and S4. In general, if we say, "the numbers 1 through 4", we mean 1, 2, 3, and 4. So he probably means that the data is pushed from the client to servers S1, S2, S3, and S4. I would further suspect that he means that any given data item goes to one of the four, not from one to the other in sequence.

A second possible reading is that the data goes through these four servers in sequence. That is, it goes from the client to S1, then from S1 to S2, from S2 to S3, and from S3 to S4.

A third possible reading is that "through" here means "by way of". You can say, "I went from New York to Chicago through Albany", meaning that I stopped off in Albany along the way. So he might possibly mean that the data goes from the client to S1 but along the way visits S4, that is, from client to S4 to S1. But frankly, I really doubt that that is what the writer meant.

You'd have to read the larger context to know which of the above he meant. Or if perhaps he had some fourth meaning in mind.

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