Symantec ALTIRIS DEPLOYMENT SOLUTION 6.9 SP4 - V1.0 Manual page 43

Automation Boot Methods
requires booting into automation mode, the boot disk must be present at the right time
to boot automation. If a complex job requires access to the production environment
during this time, the BIOS will most likely continue to boot to automation until the boot
media is removed. If this job, or a subsequent job, requires automation access again,
the boot media must be re-inserted.
To avoid these issues, some customers load the automation operating system, the
RapiDeploy imaging executable, and the image on bootable physical media. They boot a
computer, execute the necessary commands, and provide the required image files. In
this circumstance, the remote management capabilities of Deployment Server are not
being used, so the process is more manual, but it does not require network access.
This works especially well when managing thin clients or other computers where all
necessary files can fit on a single disk or USB device.
Deployment Solution 43