TITLE
Apple IIGS: Connecting Disk Drives 

Article ID: 2048
Created: 9/22/86
Modified: 10/12/87
 

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TOPIC 


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DISCUSSION 



The Apple IIGS is capable of using all drives available for the Apple IIe, as
well as drives built for the Apple IIGS, including the Disk II, Duodisk,
Unidisk, Unidisk 3.5, Profile, Apple 3.5 Drive, Apple 5.25 Drive, and SCSI-20.
Some of these drives may be plugged directly into the SmartPort on the back of
the IIGS, while others require an interface card in one of the expansion I/O
slots.

The following drives may be plugged into the SmartPort's DB-19 connector:
-- one Duodisk
-- two Unidisk 5.25 drives
-- two Unidisk 3.5 drives
-- two Apple 5.25 drives
-- two Apple 3.5 drives

Only under Prodos 16 may a combination of up to six drives be daisy-chained to
the SmartPort. The chain MUST occur in the order given below and may include
up to two (excepting the DuoDisk) in each of the following three categories:

-- nearest to IIGS (maximum of two):
1. Apple 3.5 Drives
2. Unidisk 3.5 drives

-- farthest from IIGS (maximum of two):
3. 5.25 disk drives: Disk II's, Unidisk 5.25 drives, Apple 5.25 drives
or ONE Duodisk drive

Under Prodos 8 (also known as Prodos 1.2), four drives are accessible through
the SmartPort. These may be a combination of Apple 3.5 drives, Unidisk 3.5
drives, a RAM disk, and a ROM disk, under the same order restrictions as above.

The SmartPort is mapped to slot 5, so drives connected directly to the port are
accessed as slot 5, drive 1 and slot 5, drive 2. When more than two drives are
used under Prodos 8, or if the RAM disk is active, "phantom slots" are
assigned.

To be used on the Apple IIGS, the Disk II requires a Disk II Controller Card,
just as on the Apple II or Apple IIe. The drive may be accessed through the
slot used for the card, most likely slot 6, in which case the two possible
drives are referred to as slot 6, drive 1 and slot 6, drive 2.

A SCSI Interface Card is needed to use the Apple Hard Disk 20SC on the
Apple IIGS A Profile Interface Card must be used with a 5 or 10 Megabyte
Profile, accessible by referencing the slot where the interface card resides
or by the ProFile's ProDOS pathname.

The Apple IIGS control panel allows you to select the slot from which the
computer will be booted, or you may choose to scan slots on bootup to find a
device that is ready.