Storage SCSI
Hardware
Commodore A2090
an Amiga with an A2090 must boot to Workbench, load drivers, then can access the hard drive
the A2090A can auto-boot
Commodore A2091
this is the preferred (Commodore) controller for your A2000
a Zorro II card
it can work in a Zorro III slot but only at Zorro II speed
there is a hack to double the clock speed, this should give you about a 50% boost in speed, closer to 3MB/sec
GVP
consider the Guru ROM upgrade