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From: "Gareth Bult (Encryptec)" <Gareth@Encryptec.net>
To: Josh Boyer <jdub@us.ibm.com>
Cc: Linux MTD <linux-mtd@lists.infradead.org>
Subject: Re: JFFS2 mount time
Date: Fri, 17 Dec 2004 16:46:42 +0000	[thread overview]
Message-ID: <1103302002.15927.198.camel@squizzey.bult.co.uk> (raw)
In-Reply-To: <41C3030D.8040607@us.ibm.com>

On Fri, 2004-12-17 at 10:02 -0600, Josh Boyer wrote:
> For disk devices I don't think it's required, but it could help.  Or 
> maybe your code does this at the MTD level.  I dunno.  I could be 
> spouting nonsense again ;).

Mmm, as long as writes are aligned on 2k pages and are linear / 
unidirectional, I'm not sure anything else is really a problem 
for USB flash drives ..

> Yes, it is a Journaled _Flash_ File System.  So of course it's written 
> for MTD devices.  Not sure why blkmtd.c was originally written.  Test 
> vehicle for JFFS2, "why not", "I'm bored", etc.  Who knows? :)

Mm, my point exactly , Journaled _Flash_ File System - as opposed to
Journaled _MTD_ _Flash_ File System .. !!

USB flash is still flash! - just presented via a generic interface as
opposed to an embedded one .. (AFAIK)

I guess I was sort of hoping blkmtd.c was written to enable JFFS2 to be
more generic and embedded device independent. I suspect however it was
written purely for testing purposes .. :(

As I understand it, the Flash in USB keys is identical to the MTD type
embedded devices, except that the USB keys always come with
micro-controllers that handle and optimise read/write/erase operations
and present them via a generic PC/USB based disk interface. I'm not sure
how fast MTD can be driven, but key manufacturers seem to think that
keys should be able to run at 20Mb/sec read and 10Mb/sec write [for
large block read/writes] which is much faster than is required for a key
to replace a hard disk in a workstation.

I'm thinking that JFFS2 could draw in a huge additional user base if it
catered for (or at least supported) such devices .. (!)

Gareth.

  reply	other threads:[~2004-12-17 16:46 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-15 23:19 JFFS2 mount time Gareth Bult (Encryptec)
2004-12-16  0:15 ` Josh Boyer
2004-12-16  1:02   ` Gareth Bult (Encryptec)
2004-12-16 12:53     ` Josh Boyer
2004-12-16 21:22       ` Gareth Bult (Encryptec)
2004-12-16 21:28         ` Josh Boyer
2004-12-16 21:47           ` Gareth Bult (Encryptec)
2004-12-17 12:54             ` Josh Boyer
2004-12-17 15:33               ` Gareth Bult (Encryptec)
2004-12-17 16:02                 ` Josh Boyer
2004-12-17 16:46                   ` Gareth Bult (Encryptec) [this message]
2004-12-17 17:08                     ` Artem B. Bityuckiy
2004-12-17 17:10                     ` Josh Boyer
2004-12-17 17:26                       ` Gareth Bult (Encryptec)
2004-12-17 17:35                         ` Josh Boyer
2004-12-17 18:09                           ` Gareth Bult (Encryptec)
2004-12-17 19:14                             ` jasmine
2004-12-17 20:55                               ` Gareth Bult (Encryptec)
2004-12-18 16:02                           ` Jörn Engel
2004-12-20 16:34                             ` Josh Boyer
2004-12-20 17:12                               ` Gareth Bult (Encryptec)
2004-12-21 13:09                                 ` Jörn Engel
2004-12-21 13:24                                   ` Gareth Bult (Encryptec)
2004-12-21 13:34                                     ` Jörn Engel
2004-12-18 16:19             ` Jörn Engel
2004-12-18 17:32               ` Gareth Bult (Encryptec)
2004-12-18 17:52                 ` Jörn Engel
2004-12-18 18:11                   ` Jörn Engel
2004-12-18 20:48                     ` Gareth Bult (Encryptec)
2004-12-19  2:44                       ` Jörn Engel
2004-12-21 13:30                       ` Jörn Engel
2004-12-21 13:39                         ` [PATCH 1/22] Add drivers/mtd/devices/blockmtd.c Jörn Engel
2004-12-21 13:41                           ` [PATCH 2/22] Add copyrights Jörn Engel
2004-12-21 13:42                             ` [PATCH 3/22] Remove read-only option Jörn Engel
2004-12-21 13:44                               ` [PATCH 4/22] Change init/exit functions Jörn Engel
2004-12-21 13:45                                 ` [PATCH 5/22] Remove gcc warnings Jörn Engel
2004-12-21 13:47                                   ` [PATCH 6/22] Remove debug macros Jörn Engel
2004-12-21 13:48                                     ` [PATCH 7/22] Lindent Jörn Engel
2004-12-21 13:49                                       ` [PATCH 8/22] Remove sync interface Jörn Engel
2004-12-21 13:51                                         ` [PATCH 9/22] Change parameter interface to phram-style Jörn Engel
2004-12-21 13:53                                           ` [PATCH 10/22] Cleanup macro usage Jörn Engel
2004-12-21 13:54                                             ` [PATCH 11/22] kfree simplifications Jörn Engel
2004-12-21 13:55                                               ` [PATCH 12/22] change blockmtd_sync Jörn Engel
2004-12-21 13:57                                                 ` [PATCH 13/22] remove erase regions Jörn Engel
2004-12-21 14:01                                                   ` [PATCH 14/22] Change add_device Jörn Engel
2004-12-21 14:02                                                     ` [PATCH 15/22] Rename unreadable mutex Jörn Engel
2004-12-21 14:03                                                       ` [PATCH 16/22] list changes Jörn Engel
2004-12-21 14:04                                                         ` [PATCH 17/22] Rename central struct Jörn Engel
2004-12-21 14:06                                                           ` [PATCH 18/22] Function renaming Jörn Engel
2004-12-21 14:09                                                             ` [PATCH 19/22] Fold various erase functions Jörn Engel
2004-12-21 14:10                                                               ` [PATCH 20/22] Fold various write functions Jörn Engel
2004-12-21 14:11                                                                 ` [PATCH 21/22] Default erase size Jörn Engel
2004-12-21 14:13                                                                   ` [PATCH 22/22] Readahead Jörn Engel
2004-12-21 18:42                                                   ` [PATCH 13/22] remove erase regions Christopher Hoover
2004-12-21 18:49                                                     ` Jörn Engel
2004-12-21 21:09                                                       ` Christopher Hoover
2004-12-22  2:47                                                         ` Eric W. Biederman
2004-12-22  8:59                                                           ` Jörn Engel
2004-12-22 10:05                                                             ` Eric W. Biederman
2004-12-22 10:41                                                               ` Jörn Engel
2004-12-21 13:42                           ` [PATCH 1/22] Add drivers/mtd/devices/blockmtd.c Gareth Bult (Encryptec)
2004-12-21 14:15                             ` Jörn Engel
2004-12-21 13:40                         ` JFFS2 mount time Gareth Bult (Encryptec)
2004-12-21 15:00                           ` David Woodhouse
     [not found]                             ` <1103644945.10792.175.camel@squizzey.bult.co.uk>
2004-12-21 16:04                               ` Jörn Engel
2004-12-16 13:43 ` Ferenc Havasi
2004-12-20 16:01   ` Gareth Bult (Encryptec)
2004-12-20 16:09     ` Ferenc Havasi
2004-12-20 16:39       ` Gareth Bult (Encryptec)
2004-12-20 17:48       ` Gareth Bult (Encryptec)
  -- strict thread matches above, loose matches on Subject: below --
2004-10-20 14:26 Ferenc Havasi
2004-10-20 15:26 ` [OBORONA-SPAM] " Artem B. Bityuckiy
2004-10-20 15:49   ` Ferenc Havasi
2004-10-20 15:53     ` Artem B. Bityuckiy
2004-10-21  6:29 ` Artem B. Bityuckiy
2004-10-21  6:54   ` Ferenc Havasi
2004-10-21  7:16     ` Artem B. Bityuckiy
2004-10-21 19:50       ` Ferenc Havasi
2004-10-21 12:49 ` Jarkko Lavinen
2004-10-21 19:11   ` Ferenc Havasi
2004-10-22  9:58   ` Ferenc Havasi
2004-10-21 13:24 ` David Woodhouse
2004-10-21 20:05   ` Ferenc Havasi
2004-10-22 12:44     ` Artem Bityuckiy
2004-10-25  9:36       ` Ferenc Havasi
2004-10-25 10:56         ` Artem Bityuckiy
2004-10-25 15:30           ` Ferenc Havasi
2004-10-26  9:59             ` Artem Bityuckiy
2004-10-26 10:21               ` Ferenc Havasi
2004-10-26 11:05                 ` Artem Bityuckiy
2004-10-26 13:52                   ` Ferenc Havasi
2004-10-25 11:21         ` Artem Bityuckiy
2004-10-26  9:29       ` Jarkko Lavinen
2004-10-26 10:24         ` Ferenc Havasi
2004-10-26 10:34         ` Artem Bityuckiy
2004-01-13 12:50 Jarkko Lavinen (NMP/Helsinki)
2004-01-13 13:19 ` Joakim Tjernlund
2004-01-13 13:39 ` David Woodhouse
2004-01-13 15:25   ` Kenneth Johansson
2004-01-13 15:30     ` David Woodhouse
2004-01-13 16:21       ` Kenneth Johansson
2004-01-13 17:29         ` Jörn Engel
2004-01-13 17:40           ` Kenneth Johansson
2004-01-13 18:43             ` Jörn Engel
2005-01-04 15:00 ` Steven Scholz
2005-01-05 10:45   ` Artem B. Bityuckiy
2005-01-05 11:10     ` Ferenc Havasi
2005-01-05 11:24       ` Steven Scholz
2005-01-05 11:45         ` Artem B. Bityuckiy
2005-01-06 10:50           ` Ferenc Havasi
2005-01-10 15:14           ` Steven Scholz
2005-01-10 15:25             ` Steven Scholz
2005-01-11  8:26             ` Ferenc Havasi
2005-01-11  8:34               ` Steven Scholz

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