I have the rt4 and rt53 disks and the emulator...
RL, 4 units
unit 0, 2621KW, attached to rtv4_rk.dsk, write enabled, RL01
unit 1, 2621KW, not attached, write enabled, autosize
unit 2, 2621KW, not attached, write enabled, autosize
unit 3, 2621KW, not attached, write enabled, autosize
sim> boot rl0
?BOOT-U- I/O error
HALT instruction, PC: 000724 (BR 722)
sim>
What is the proper incantation to boot this?
What is your host OS/architecture? What version of the emulator are you
running.
Basically you're doing the correct thing to boot.
Zane