System Overview

SBCs are used in the nEDM experiment to:

• readout over the VME bus
• communicate with ORCA
• Communicate with the CASCADE detectors.

All SBCs run a read-only linux system (similar to the Raspberry Pis) that allows them to be safely removed from power at all times.

Backup images

• ORCA - Active Coil Compensation/Struck readout: a backup image for this SBC is here (Cluster server ) (Osthalle server).

• CASCADE detectors - A backup image for this SBC is here (Cluster server ) (Osthalle server).

Both of these can be flashed to a CompactFlash card:

gunzip -c sbc.backup.gz | sudo dd of=/dev/sd_card

Note that after this, the file system on the second partition will have to be rebuilt, which can be done on a linux machine that has access to the CompactFlash card. For example, if the card is on /dev/sbc, this can be done:

mkfs.ext3 /dev/sbc2

Updating the software on a running system

After logging in to the SBC as as root (see the wiki), the ro (read-only) and rw (read-write) alias commands should be available. A normal system update would look like:

rw # Make read-write
# ... Perform updates to the file system
# ...    install new software, etc.
ro # Make read-only

The aliases are (for reference):

alias rw='mount -o remount,rw /'
alias ro='mount -o remount,ro /'