Re: Have ext3 on SanDisk CF but can't disable write-back cachingas kernel instructs
From: Michael Schnell (mschnell_at_lumino.de)
Date: 07/14/03
- Next message: Michael Schnell: "Re: Have ext3 on SanDisk CF but can't disable write-back caching as kernel instructs"
- Previous message: Michael Schnell: "Re: Have ext3 on SanDisk CF but can't disable write-back caching as kernel instructs"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Mon, 14 Jul 2003 08:34:19 +0200
>
> I don't think so. Any disk write is based on a sector base. Using a "by
> sector" checksum, you can determine a garbled sector (an there can't be
> more than one). If you additionally use journalling, it is safe (except
> the checksum fails or the house is burning down ;-).
>
The CF decides by itself how to sore the sector. Internally they use
flash pages much bigger than sectors and do a complicated housekeeping
involving a RAM at least as big as a flash page. So if you write a
sector, other sectors already stored in the Flash will be moved. If
power is turned off in the process, internal allocation tables can be
damaged, destroying everything stored in the device. I heard that there
are (or will be) CF cards that include a battery to prevent this, but I
did not yet see any specs.
-Michael
- Next message: Michael Schnell: "Re: Have ext3 on SanDisk CF but can't disable write-back caching as kernel instructs"
- Previous message: Michael Schnell: "Re: Have ext3 on SanDisk CF but can't disable write-back caching as kernel instructs"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
