From f39ab529790b36ffa9ecdd2fb5d9f0139619cc52 Mon Sep 17 00:00:00 2001
From: warner <>
Date: Thu, 7 Jan 2010 01:48:32 +0000
Subject: [PATCH] share layout: think about round trips

[Imported from Trac: page NewImmutableEncodingDesign, version 5]
---
 NewImmutableEncodingDesign.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/NewImmutableEncodingDesign.md b/NewImmutableEncodingDesign.md
index cca95b5..1fed58a 100644
--- a/NewImmutableEncodingDesign.md
+++ b/NewImmutableEncodingDesign.md
@@ -37,6 +37,17 @@ This page is for designing the encoding format for these new immutable files.
      (servers can compare share contents against the UEB, and we could put a
      copy of the UEB hash into the share, but servers would continue to be
      unable to make sure the share was in the right place)
+ * make the share layout more deterministic, to get rid of the RTT that's
+   needed to fetch the offset table before we can fetch the UEB. Maybe
+   reserve space for the UEB at the start of the share (but that makes it hard
+   to have an extensible open-ended UEB).
+ * since we probably do need to stick with the offset table, see if there's a
+   way to guarantee having the same offsets across all shares. This would allow
+   the table pulled (and validated) from one share to be used to compute read
+   vectors for all other shares. We probably already have identical tables,
+   but it'd be nice to make the guarantee explicit. The tables need to be
+   covered by the UEB, else we can't share them: the first read might be from
+   a corrupted share, and that would malign (hah!) the other shares.
 
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