Do this ( we do this ).
1. Use a flash disk for booting.
2. Boot everything into a ramdisk ( no disk mounted )
3. Use a switchmode power supply with large capacitor than normal on the
unregulated input.
4. set a power fail flag to an interrupt input ( eg serial port control
line)
5. Use standard UPS type code to save essential items to disk.
( you will not have to shutdown the filesystem .. its in RAM :) )
6. You will have between 3 and 10 seconds to do this - plenty.
regards etc.
-----Original Message-----
From: Magnus Ohrstrom (Magnus �hrstr�m) <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Tuesday, August 17, 1999 7:49 PM
Subject: more pull-the-plug problems
While dealing with a pull-the-plug scenario for
an embedded linux pump controller, I have browsed
this news group for some answers.
My idea was, and was also mentioned in a few postings,
to have the file system mounted ro and have all data stored
in a ram disk. At a specific time interval, the disk is remounted
rw and the data is written down to disk. The disk is then again mounted ro.
We can live with the risk of a shutdown in the writing phase, no
problem. But still there are some questions:
which parts of the file structure must be rw? Is /dev and /var enough?
Mount wont let me remount the disk -> ro after disk writes. Do you have
to do this in a special way or what?
magnus oe
________________________
.magnus ohrstrom
.Flygt MST division
--
To unsubscribe from this list, send a message to [EMAIL PROTECTED]
with the command "unsubscribe linux-embedded" in the message body.
For more information, see <http://waste.org/mail/linux-embedded>.
--
To unsubscribe from this list, send a message to [EMAIL PROTECTED]
with the command "unsubscribe linux-embedded" in the message body.
For more information, see <http://waste.org/mail/linux-embedded>.
