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[PATCH] doc: 1MiB-alignment is not enough for cheap flash drives
From: |
Jim Meyering |
Subject: |
[PATCH] doc: 1MiB-alignment is not enough for cheap flash drives |
Date: |
Wed, 02 Jan 2013 12:56:20 +0100 |
FYI,
>From 21be64fc6ef60a1e9dc7bc352131be58cc59d61d Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Wed, 2 Jan 2013 12:52:14 +0100
Subject: [PATCH] doc: 1MiB-alignment is not enough for cheap flash drives
* doc/parted.texi: Add an example that aligns to 4GiB, and
reference Arnd Bergman's LWN article.
---
doc/parted.texi | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/doc/parted.texi b/doc/parted.texi
index b8db19d..008c383 100644
--- a/doc/parted.texi
+++ b/doc/parted.texi
@@ -14,7 +14,7 @@ and manipulating partition tables.
@ifnottex @c texi2pdf don't understand copying and insertcopying ???
@c modifications must also be done in the titlepage
@copying
-Copyright @copyright{} 1999-2012 Free Software Foundation, Inc.
+Copyright @copyright{} 1999-2013 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -577,15 +577,44 @@ partition table.
@item ufs
@end itemize
-Example:
+For example, the following creates a logical partition that will contain
+an ext2 file system. The partition will start at the beginning of the disk,
+and end 692.1 megabytes into the disk.
@example
(parted) @kbd{mkpart logical 0.0 692.1}
@end example
-Create a logical partition that will contain an ext2 file system. The
-partition will start at the beginning of the disk, and end 692.1
-megabytes into the disk.
+Now, we will show how to partition a low-end flash
+device (``low-end'', as of 2011/2012).
+For such devices, you should use 4MiB-aligned address@hidden
+Cheap flash drives will be with us for a long time to
+come, and, for them, 1MiB alignment is not enough.
+Use at least 4MiB-aligned partitions.
+For details, see Arnd Bergman's article,
address@hidden://http://lwn.net/Articles/428584/} and its many comments.}.
+This command creates a tiny place-holder partition at the beginning, and
+then uses all remaining space to create the partition you'll actually use:
+
address@hidden
+$ @kbd{parted -s /dev/sdX -- mklabel msdos \}
address@hidden mkpart primary fat32 64s 4MiB \}
address@hidden mkpart primary fat32 4MiB -1s}
address@hidden example
+
+Note the use of @samp{--}, to prevent the following @samp{-1s} last-sector
+indicator from being interpreted as an invalid command-line option.
+The above creates two empty partitions. The first is unaligned and tiny,
+with length less than 4MiB.
+The second partition starts precisely at the 4MiB mark
+and extends to the end of the device.
+
+The next step is typically to create a file system in the second partition:
+
address@hidden
+$ @kbd{mkfs.vfat /dev/sdX2}
address@hidden example
+
@end deffn
--
1.8.1
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