====== Embedded Debian ======

[[http://www.nope.tv/article225.html|This page]] was used as a starting point, and then heavily modified.

===== Installation =====

Do a standard [[Debian]] installation to the drive. The kernel argument **ide=nodma** may be required, depending on the CF device used.

===== Ram Disks =====

Some filesystems should be mounted as ramdisks to minimize writes to the CF device. Add these lines to **/etc/fstab**.

  tmpfs /var/run  tmpfs defaults 0 0
  tmpfs /var/lock tmpfs defaults 0 0
  tmpfs /var/log  tmpfs defaults 0 0
  tmpfs /tmp      tmpfs defaults 0 0

==== preinit ====

Since these filesystems need to be mounted before **/sbin/init** starts launching services which need to access them, we need to run a helper script before **/sbin/init**. Create the following file as **/sbin/preinit** and set it's permissions to **755**.

  #!/bin/bash
  
  echo "Disable DMA"
  hdparm -d0 /dev/hda
  echo "Enable some power management and disable spindown"
  hdparm B64 -S0 /dev/hda
  echo "Enable 32-bit I/O"
  hdparm -c3 /dev/hda
  
  echo "Creating tmpfs in /var/log"
  mount -n -t tmpfs tmpfs /var/log
  echo "Copy /var/log"
  cp -a /var/log_persistent/* /var/log
  
  echo "Creating tmpfs in /var/run"
  mount -n -t tmpfs tmpfs /var/run
  echo "Copy /var/run"
  cp -a /var/log_persistent/* /var/log
  
  echo "Done, resume normal operations..."
  exec /sbin/init

==== GRUB ====

 Add **init=/sbin/preinit** to the kernel options in **/boot/grub/menu.lst** to tell the kernel to run the preinit script at boot.



===== ACPI =====

The ACPI subsystem will try to turn DMA back on, which will cause intermittent issues.

Edit **/etc/acpi/sleep.sh** and change the hdparm lines with **-d 1** to **-d 0**.