I have acquired some Dell PowerEdge 1950 servers. Within each seems to be a single erased 3.5 inch SATA hard disk. There does not appear to be a DVD drive. They do not boot a Flash drive (containing an installable Ubuntu) on a USB port. The setup menu shows 2 options for booting: an IDE CD-ROM device and Hard drive C. Perhaps some but not all servers offer a third option of booting from a "NIC".
The facilities I have to work with are a typical laptop (Ubuntu), an external DVD drive (USB), a 2.5 inch SATA circuit board (USB) extracted from a "drive enclosure", and a 48 port switch.
What is my best option for getting Ubuntu booting on each and every server hard disk? I accept that I may have to purchase some items.
Correction: I found the optical drive and quite possibly that solves the problem.