Can I startup my iBook with a Powerbook? Or, USB drive?

[Jay Boshara]

I have a 366 iBook running Panther that has only one USB 1.0 connection (no
FireWire).  Is it possible to connect my wife¹s 800 TiBook (also running
Panther) to my iBook via USB and use her TiBook as a startup disk for my
iBook in case of emergency?

If not, is there a cheap external USB 1.0 drive I can buy on which I can
install another Panther operating system to be used as a startup disk in
case of emergency (and for backups)?  My iBook¹s 5.6 GB drive is showing
signs of failing and I just can¹t afford to buy a new computer right now,
and replacing the drive in this old iBook would be like putting a new engine
in a crappy 1972 Dodge Dart.