Amiga Floppy Disk Drives

Supported Number of Floppy Drives

The Amiga is designed to support up to four floppy drives, with the following device names:

DF0:

DF1:

DF2:

DF3:

Select Lines

To utilise these four floppy drives, the Amiga has four select lines to identify each drive. These select lines are called:

SEL0

SEL1

SEL2

SEL3

Drive Select

Each floppy drive have drive select jumpers (hard wired or user configurable) to set which of these select lines it should respond to.

S0

S1

S2

S3

Most drives will jumpers for at least two of these (S0 and S1), but some have more (S2 and S3).

Daisy Chain

The Amiga design makes use of a daisy chain method to allow up to three external drives to be connected using only one external floppy drive interface on the Amiga. This requires for the external floppy drive enclosure unit to have a passthrough interface to be able to support this daisy chain method.

Depending one where the internal or external floppy drive is connected in this daisy chain, will determine which floppy device name (DF0, DF1, DF2, DF3) it will use.

Some external floppy drive enclosures does not have a passthrough interface. These effectively terminate the daisy chain and is typically connected at the end of the daisy chain.

Enable / Disable Switch

The external drive enclosures may also have an Enable / Disable switch connected to its SEL0 line. This allows you to quickly enable or disable the drive at the flip of a switch.

Logical Diagram

Below is a logical representation of how this daisy chain method works showing how the Select Lines and Drive Select jumpers impact whether it works or not. This example is based on an Amiga A500(+), A600 and A1200.