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| author | Connor Zanin <cnnrznn@gmail.com> | 2016-12-11 22:32:24 -0500 |
|---|---|---|
| committer | Connor Zanin <cnnrznn@gmail.com> | 2016-12-11 22:32:24 -0500 |
| commit | 44c0b2611d4ab0dc6b8ab8d93854ff0b982f3e85 (patch) | |
| tree | 47c9f2d2787936560a5a8dceb6fdac1307e3e092 /chapter/4/dist-langs.md | |
| parent | 5d64d3aa62c8e08457c71e1d60cd60433d1234c3 (diff) | |
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Diffstat (limited to 'chapter/4/dist-langs.md')
| -rw-r--r-- | chapter/4/dist-langs.md | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/chapter/4/dist-langs.md b/chapter/4/dist-langs.md index d4fbed6..481a12c 100644 --- a/chapter/4/dist-langs.md +++ b/chapter/4/dist-langs.md @@ -102,7 +102,12 @@ To accomplish this, Mirage uses a protocol for requesting read or write access t Depending on the permissions of the current "owner" of a page, the page may be invalidated on other nodes. The behavior of the protocol is outlined by the table below. - +| State of Owner | State of Requester | Clock Check? | Invalidation? | +|----------------|--------------------|--------------|-------------------------------------------------------------| +| Reader | Reader | No | No | +| Reader | Writer | Yes | Yes, Requester is possibly sent current version of the page | +| Writer | Reader | Yes | No, Owner is demoted to Reader | +| Writer | Writer | Yes | Yes | Crucially, the semantics of this protocol are that at any time there may only be either (1) a single writer or (2) one or more readers of a page. When a single writer exists, no other copies of the page are present. |