Its common for external SCSI Ports, on an A1200, to be a D25 fitted to a knock-out plastic port just behind the Floppy Drive.
The BASIC Driver and File System go in DEVS/DOSDrivers (often CD0) and L/ (AmiCDFS, CacheCDFS, or other).
The Driver is actually a TEXT File similar to this:
/* $VER: CD0 2.36 (22.08.96)
*
* CD-ROM filesystem mount entry
*
* Created by CU Amiga CD AmiCDFS installer
*/
Device = 2060scsi.device
FileSystem = L:AmiCDFS
Flags = 0
BlocksPerTrack = 32
BlockSize = 2048
Reserved = 0
LowCyl = 0
HighCyl = 11000
Surfaces = 1
Buffers = 64
BufMemType = 1
Mask = 0x7fffffff
GlobVec = -1
Priority = 10
DosType = 0x43444653
StackSize = 600
Mount = 1
FORCELOAD = 1
Control = "LC BL=8 FB=32"
/* Unit number is given in icon tooltype
*
* Control field template:
*
* LC=LOWERCASE/S,CS=CASESENSE/S,
* HF=HFSFIRST/S,TD=TRACKDISK/S,
* BL=BUFFERLINES/K/N,FB=FILEBUFFERS/K/N,
* DC=DISKCHANGE/K/N,MT=MOTORTIME/K/N,
* SD=STARTDELAY/K/N,TDC=TDCHANGE/S,
* TOSHIBA/S,OLDMODE/S
*/
. . . . . . . . . . . . . . . . . . . . . . . . .
The Device = MUST match your own {NAME}scsi.device
The FileSystem = MUST point to your own CD Filing System.
The Unit number is the ACTUAL SCSI Unit No switched on the CD Drive itself. This can be a VALUE after a = or, as in my own case, indicated in Icon Tooltype. A Single LMB click on the CD0 Icon will activate a data-field when the RMB Opens Icons/Information with the THIRD Workbench Menu item. My own shows UNIT=0 in the Tooltypes field.
A Default Tool- C:Mount can be shown here too. This makes the Driver visible to the system.