Rodos <[EMAIL PROTECTED]>
> Any suggestions for setting up Linux for this environment?

you said it doesn't need to do any local I/O.
So set it up with / mounted read-only.
I did this just recently at work on a similar sounding
project to you, except in solaris x86.

All the bits that the OS wants to write to whilst running
(like under /var/adm, /var/log, /etc and so on) are copied
at the beginning of booting to /tmp and there are links from
the original place to /tmp/whatever.  In solaris everything under
/tmp resides in memory.  I didn't have any swap, a bare solaris
install (37Mb), 128Mb of RAM and a 96Mb flash device as the disk.

The bit that was tricky for me was the box had to be able
to save some local config stuff and keep certain log files
whilst still maintaining the ability to survive almost
anything (eg. total power loss).  It's a compact-PCI chassis
(rack mounted) with redundant power supplies etc but I
couldn't get around buffered writes under solaris ufs to
flash so I split the flash into 5 solaris slices (one fdisk
partition). s0 is root mounted read-only, and s3,s4,s5,s6 are
for storing the data I want to keep.  I wrote my own mini
filesystem and disk manager (pretty rough) that does straight
read/writes (with a max of a 5 sec buffer, it goes by
time rather than bytes of data) to the raw device.  So worst
case is the most you'll lose is 5 secs of data.

All this ensures root is always ok and the box can never get
stuck on an fsck, it should also never require user intervention
unless the flash itself dies.

I was originally looking at using QNX/Neutrino for this rather
than solaris as it doesn't have these filesystem/buffering
problems but hit other problems with support for other devices
we're using and lack of a C++ compiler.

Dave.
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