Git Mailing List Archive mirror
 help / color / mirror / Atom feed
From: Taylor Blau <me@ttaylorr.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>,
	git@vger.kernel.org, derrickstolee@github.com,
	jrnieder@gmail.com, larsxschneider@gmail.com, tytso@mit.edu
Subject: Re: [PATCH v4 02/17] pack-mtimes: support reading .mtimes files
Date: Fri, 20 May 2022 18:37:51 -0400	[thread overview]
Message-ID: <YogYP03hDH8hZqUV@nand.local> (raw)
In-Reply-To: <220520.86bkvs3bfm.gmgdl@evledraar.gmail.com>

On Fri, May 20, 2022 at 09:32:50AM +0200, Ævar Arnfjörð Bjarmason wrote:
>
> On Thu, May 19 2022, Junio C Hamano wrote:
>
> > Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> >
> >> On Wed, May 18 2022, Taylor Blau wrote:
> >>
> >> Nit:
> >>
> >>> +  - A 4-byte magic number '0x4d544d45' ('MTME').
> >>> +
> >>> +  - A 4-byte version identifier (= 1).
> >>> +
> >>> +  - A 4-byte hash function identifier (= 1 for SHA-1, 2 for SHA-256).
> >>
> >> Here we let it suffice that later we'll say "All 4-byte numbers are in
> >> network order".
> >>
> >>> +  - A table of 4-byte unsigned integers in network order. The ith
> >>
> >> But here we call out "network order" explicitly, shouldn't this just be
> >> s/ in network order//?
> >>
> >>> +    value is the modification time (mtime) of the ith object in the
> >>> +    corresponding pack by lexicographic (index) order. The mtimes
> >>> +    count standard epoch seconds.
> >>> +
> >>> +  - A trailer, containing a checksum of the corresponding packfile,
> >>> +    and a checksum of all of the above (each having length according
> >>> +    to the specified hash function).
> >>> +
> >>> +All 4-byte numbers are in network order.
> >>
> >> I.e. this is sufficient.
> >
> > Very good eyes.  One explicit mention among several others can
> > indeed be misleading the readers.
> >
> > When asked for "network order", all your search engines show are
> > entries about "network byte order", so let's use that longer form of
> > spelling.
>
> *Nod*, note that "network order" is on "master" already though,
> i.e. this section re-used a template introduced in 2f4ba2a867f
> (packfile: prepare for the existence of '*.rev' files, 2021-01-25) just
> above this hunk.
>
> Before that change the rest of the file used "network byte order"
> consistently.

Hmm. e0d1bcf825 (multi-pack-index: add format details, 2018-07-12)
(which predates 2f4ba2a867f by a few years) introduced the first use of
"network order" as opposed to "network byte order".

I think it's worth cleaning this up, but let's do it in two parts.
I'll send a rerolled version of tb/cruft-packs that moves the "All
4-byte numbers are in network order" to the top of that section,
switching "network order" for "network byte order", and dropping other
mentions of "network [byte] order" from that section.

Then, we can come back later and perhaps do something like the following
(but I don't want to do it now and tie up this series with semi-related
cleanups):

--- 8< ---

diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index b520aa9c45..2591a410fd 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -276,6 +276,8 @@ Pack file entry: <+

 == pack-*.rev files have the format:

+All 4-byte numbers are in network byte order.
+
   - A 4-byte magic number '0x52494458' ('RIDX').

   - A 4-byte version identifier (= 1).
@@ -283,8 +285,8 @@ Pack file entry: <+
   - A 4-byte hash function identifier (= 1 for SHA-1, 2 for SHA-256).

   - A table of index positions (one per packed object, num_objects in
-    total, each a 4-byte unsigned integer in network order), sorted by
-    their corresponding offsets in the packfile.
+    total, each a 4-byte unsigned integer), sorted by their
+    corresponding offsets in the packfile.

   - A trailer, containing a:

@@ -292,8 +294,6 @@ Pack file entry: <+

     a checksum of all of the above.

-All 4-byte numbers are in network order.
-
 == pack-*.mtimes files have the format:

 All 4-byte numbers are in network byte order.
@@ -322,7 +322,7 @@ the body into "chunks" and provide a lookup table at the beginning of the
 body. The header includes certain length values, such as the number of packs,
 the number of base MIDX files, hash lengths and types.

-All 4-byte numbers are in network order.
+All 4-byte numbers are in network byte order.

 HEADER:

@@ -397,8 +397,8 @@ CHUNK DATA:

 	[Optional] Bitmap pack order (ID: {'R', 'I', 'D', 'X'})
 	    A list of MIDX positions (one per object in the MIDX, num_objects in
-	    total, each a 4-byte unsigned integer in network byte order), sorted
-	    according to their relative bitmap/pseudo-pack positions.
+	    total, each a 4-byte unsigned integer), sorted according to their
+	    relative bitmap/pseudo-pack positions.

 TRAILER:


--- >8 ---

Thanks,
Taylor

  reply	other threads:[~2022-05-20 22:37 UTC|newest]

Thread overview: 201+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-29 22:25 [PATCH 00/17] cruft packs Taylor Blau
2021-11-29 22:25 ` [PATCH 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2021-12-02 14:33   ` Derrick Stolee
2021-12-03 21:53     ` Taylor Blau
2021-12-04 22:20   ` Elijah Newren
2021-12-04 23:32     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2021-12-02 15:06   ` Derrick Stolee
2021-12-02 22:32     ` brian m. carlson
2021-12-03 22:24     ` Taylor Blau
2022-01-07 19:41       ` Taylor Blau
2021-11-29 22:25 ` [PATCH 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2021-11-29 22:25 ` [PATCH 04/17] chunk-format.h: extract oid_version() Taylor Blau
2021-12-02 15:22   ` Derrick Stolee
2021-12-03 22:40     ` Taylor Blau
2021-12-06 17:33       ` Derrick Stolee
2021-11-29 22:25 ` [PATCH 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2021-12-02 15:36   ` Derrick Stolee
2021-12-03 23:04     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2021-12-06 21:16   ` Derrick Stolee
2022-02-23 22:24     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2021-11-29 22:25 ` [PATCH 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2021-12-06 21:44   ` Derrick Stolee
2022-03-01  2:48     ` Taylor Blau
2021-12-07 15:17   ` Derrick Stolee
2022-02-23 23:34     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2021-11-29 22:25 ` [PATCH 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2021-11-29 22:25 ` [PATCH 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2021-12-07 15:30   ` Derrick Stolee
2022-02-23 23:35     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2021-12-05 20:46   ` Junio C Hamano
2022-03-01  2:00     ` Taylor Blau
2021-12-07 15:38   ` Derrick Stolee
2022-02-23 23:37     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2021-11-29 22:25 ` [PATCH 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2021-11-29 22:25 ` [PATCH 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2021-11-29 22:25 ` [PATCH 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2021-11-29 22:25 ` [PATCH 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2021-12-03 19:51 ` [PATCH 00/17] " Junio C Hamano
2021-12-03 20:08   ` Taylor Blau
2021-12-03 20:47     ` Taylor Blau
2022-03-02  0:57 ` [PATCH v2 " Taylor Blau
2022-03-02  0:58   ` [PATCH v2 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-03-02  0:58   ` [PATCH v2 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-03-02 20:22     ` Derrick Stolee
2022-03-02 21:33       ` Taylor Blau
2022-03-02  0:58   ` [PATCH v2 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-03-02  0:58   ` [PATCH v2 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-03-02  0:58   ` [PATCH v2 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-03-02  0:58   ` [PATCH v2 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-03-02  0:58   ` [PATCH v2 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-03-02  0:58   ` [PATCH v2 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-03-02  0:58   ` [PATCH v2 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-03-02 20:19     ` Derrick Stolee
2022-03-02 21:28       ` Taylor Blau
2022-03-02  0:58   ` [PATCH v2 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-03-02  0:58   ` [PATCH v2 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-03-02  7:42     ` Junio C Hamano
2022-03-02 15:54       ` Taylor Blau
2022-03-02 19:57         ` Derrick Stolee
2022-03-02  0:58   ` [PATCH v2 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-03-02  0:58   ` [PATCH v2 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-03-02  0:58   ` [PATCH v2 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-03-02  0:58   ` [PATCH v2 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-03-02  0:58   ` [PATCH v2 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-03-02  0:58   ` [PATCH v2 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-03-02 20:23   ` [PATCH v2 00/17] " Derrick Stolee
2022-03-02 21:36     ` Taylor Blau
2022-03-03  0:20 ` [PATCH v3 " Taylor Blau
2022-03-03  0:20   ` [PATCH v3 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-03-07 18:03     ` Jonathan Nieder
2022-03-22  1:16       ` Taylor Blau
2022-03-22 21:45         ` Jonathan Nieder
2022-03-22 22:02           ` Taylor Blau
2022-03-22 23:04             ` Jonathan Nieder
2022-03-23  1:01               ` Taylor Blau
2022-03-28 18:46                 ` Taylor Blau
2022-03-28 20:55                   ` Junio C Hamano
2022-03-28 21:21                     ` Taylor Blau
2022-03-29 15:59                       ` Junio C Hamano
2022-03-30  2:23                         ` Taylor Blau
2022-03-30 13:37                           ` Junio C Hamano
2022-03-30 17:30                             ` Taylor Blau
2022-03-03  0:20   ` [PATCH v3 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-03-03  0:20   ` [PATCH v3 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-03-03  0:20   ` [PATCH v3 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-03-03 16:30     ` Ævar Arnfjörð Bjarmason
2022-03-03 23:32       ` Taylor Blau
2022-03-04  0:16         ` Junio C Hamano
2022-03-03  0:20   ` [PATCH v3 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-03-03 16:45     ` Ævar Arnfjörð Bjarmason
2022-03-03 23:35       ` Taylor Blau
2022-03-04 10:40         ` Ævar Arnfjörð Bjarmason
2022-03-03  0:20   ` [PATCH v3 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-03-03  0:21   ` [PATCH v3 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-03-03  0:21   ` [PATCH v3 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-03-03  0:21   ` [PATCH v3 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-03-03  0:21   ` [PATCH v3 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-03-03  0:21   ` [PATCH v3 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-03-03  0:21   ` [PATCH v3 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-03-03  0:21   ` [PATCH v3 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-03-03  0:21   ` [PATCH v3 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-03-03  0:21   ` [PATCH v3 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-03-03  0:21   ` [PATCH v3 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-03-03  0:21   ` [PATCH v3 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-03-03  1:29   ` [PATCH v3 00/17] " Derrick Stolee
2022-05-18 23:10 ` [PATCH v4 " Taylor Blau
2022-05-18 23:10   ` [PATCH v4 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-05-19 14:04     ` Junio C Hamano
2022-05-18 23:10   ` [PATCH v4 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-19 10:40     ` Ævar Arnfjörð Bjarmason
2022-05-19 15:21       ` Junio C Hamano
2022-05-20  7:32         ` Ævar Arnfjörð Bjarmason
2022-05-20 22:37           ` Taylor Blau [this message]
2022-05-18 23:10   ` [PATCH v4 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-05-18 23:11   ` [PATCH v4 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-05-19 11:44     ` Ævar Arnfjörð Bjarmason
2022-05-18 23:11   ` [PATCH v4 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-05-18 23:11   ` [PATCH v4 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-05-18 23:11   ` [PATCH v4 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-05-18 23:11   ` [PATCH v4 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-05-19 10:04     ` Junio C Hamano
2022-05-19 15:16       ` Junio C Hamano
2022-05-20 22:52         ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-05-18 23:11   ` [PATCH v4 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-05-18 23:11   ` [PATCH v4 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-05-18 23:11   ` [PATCH v4 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-05-19 11:29     ` Ævar Arnfjörð Bjarmason
2022-05-20 22:39       ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-05-18 23:11   ` [PATCH v4 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-05-18 23:11   ` [PATCH v4 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-05-19 11:32     ` Ævar Arnfjörð Bjarmason
2022-05-20 22:42       ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-05-18 23:11   ` [PATCH v4 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-05-18 23:48   ` [PATCH v4 00/17] " Derrick Stolee
2022-05-20 23:19     ` Junio C Hamano
2022-05-20 23:30       ` Taylor Blau
2022-05-19 11:42   ` [RFC PATCH 0/2] Utility functions for duplicated pack(write) code Ævar Arnfjörð Bjarmason
2022-05-19 11:42     ` [RFC PATCH 1/2] packfile API: add and use a pack_name_to_ext() utility function Ævar Arnfjörð Bjarmason
2022-05-19 15:40       ` Junio C Hamano
2022-05-19 11:42     ` [RFC PATCH 2/2] hash API: add and use a hash_short_id_by_algo() function Ævar Arnfjörð Bjarmason
2022-05-19 15:50       ` Junio C Hamano
2022-05-19 19:07         ` Ævar Arnfjörð Bjarmason
2022-05-19 15:31     ` [RFC PATCH 0/2] Utility functions for duplicated pack(write) code Junio C Hamano
2022-05-19 11:54   ` [PATCH v4 00/17] cruft packs Ævar Arnfjörð Bjarmason
2022-05-20 23:17 ` [PATCH v5 " Taylor Blau
2022-05-20 23:17   ` [PATCH v5 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-05-20 23:17   ` [PATCH v5 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-24 19:32     ` Jonathan Nieder
2022-05-24 19:44       ` rsbecker
2022-05-24 22:25         ` Taylor Blau
2022-05-24 23:24           ` rsbecker
2022-05-25  0:07             ` Taylor Blau
2022-05-25  0:20               ` rsbecker
2022-05-25  9:11               ` adding new 32-bit on-disk (unsigned) timestamp formats (was: [PATCH v5 02/17] pack-mtimes: support reading .mtimes files) Ævar Arnfjörð Bjarmason
2022-05-25 13:30                 ` Derrick Stolee
2022-05-25 21:13                   ` Taylor Blau
2022-05-26  0:02                     ` Ævar Arnfjörð Bjarmason
2022-05-26  0:12                       ` Taylor Blau
2022-05-24 22:21       ` [PATCH v5 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-25  7:48         ` Jonathan Nieder
2022-05-25 21:36           ` Taylor Blau
2022-05-25 21:58             ` rsbecker
2022-05-25 22:59               ` Taylor Blau
2022-05-25 23:02     ` Taylor Blau
2022-05-26  0:30       ` Junio C Hamano
2023-06-01 13:01     ` Andreas Schwab
2022-05-20 23:17   ` [PATCH v5 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-05-20 23:17   ` [PATCH v5 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-05-20 23:17   ` [PATCH v5 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-05-20 23:17   ` [PATCH v5 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-05-20 23:17   ` [PATCH v5 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-05-20 23:17   ` [PATCH v5 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-05-20 23:17   ` [PATCH v5 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-05-20 23:17   ` [PATCH v5 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-05-20 23:18   ` [PATCH v5 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-05-20 23:18   ` [PATCH v5 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-05-20 23:18   ` [PATCH v5 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-05-20 23:18   ` [PATCH v5 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-05-20 23:18   ` [PATCH v5 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-05-20 23:18   ` [PATCH v5 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-06-19  5:38     ` René Scharfe
2022-06-21 15:58       ` Junio C Hamano
2022-05-20 23:18   ` [PATCH v5 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-05-21 11:17   ` [PATCH v5 00/17] " Ævar Arnfjörð Bjarmason
2022-05-24 19:39     ` Jonathan Nieder
2022-05-24 21:50       ` Taylor Blau
2022-05-24 21:55         ` Ævar Arnfjörð Bjarmason
2022-05-24 22:12           ` Taylor Blau
2022-05-25  7:53             ` Jonathan Nieder
2022-05-25 19:59               ` Derrick Stolee
2022-05-25 21:09                 ` Taylor Blau
2022-05-26  0:06                   ` Ævar Arnfjörð Bjarmason

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YogYP03hDH8hZqUV@nand.local \
    --to=me@ttaylorr.com \
    --cc=avarab@gmail.com \
    --cc=derrickstolee@github.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=jrnieder@gmail.com \
    --cc=larsxschneider@gmail.com \
    --cc=tytso@mit.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).