Irix, like most Commercial Unixen, can be installed over a network, however installation is usually difficult from other operating systems.
Due to my attempts to install Irix 6.5 on my Indy from a Linux host, I managed to work out the magic combinations to make it work.
You can follow the installation directions for remote host installations as listed in the Irix software installation manual, but you need to be aware of a few caveats.
Running a bootp server is a good idea. Irix uses it during boot to get things like routers addresses and netmask details.
Do not list a bootfile or bootfile path. This interferes with the install from remote directory option in your bootprom.
Make sure that the dist directory on your Installation tools CD-ROM is accessible via tftpd, since the miniroot and boot images are tftp'd from that directory.
This is the nasty caveat.
Irix systems have ksh as their /bin/sh. The inst system expects that the system shell is a korn shell, and will fail if /bin/sh is bash.
pdksh works in this capacity fine.
CD-ROMs and paths
If you're remote installing from CD-ROM drives, and not directories, mount the CD-ROMs on /CDROM. inst recognises this path as a removable CD-ROM drive.
The IRIX 6.5 distribution CDs are written with efs. Linux has a fs module for efs in 2.2.18 which reads them fine. I haven't tried other revisions of the kernel.