Overview
Amiga Forever 2005 and higher include support for SCSI both in
the WinUAE emulation component and as part of the tools which
are preinstalled in the Workbench environment.
The procedures described here are fully supported only on
Windows XP, Windows Server 2003, Windows Vista, Windows 7 and Windows Server 2008,
using WinUAE 1.1.1 and higher.
Support for Windows 2000 is limited in some cases, reflecting
system API limitations. SCSI and the other low-level device
access interfaces and procedures described here are not supported in WinFellow.
Special thanks to Toni Wilen for assisting in the preparation
of this document.
Important: Because Amiga SCSI devices and
media are generally quite old, we recommend that you copy your
Amiga data to new storage media as soon as you are able to
access it. If possible, prepare the required interface and
software first, and then switch on your legacy hardware only
once, and immediately proceed with the transfer.
SCSI Devices and IDs (Units)
From within the operating system as preinstalled in Amiga Forever you
have the option to use one of two devices:
- uaehf.device (for hardfiles, "real" hard disks
and other block-type devices);
- uaescsi.device (optimized both for SCSI and for
CD-ROM-like hardware, e.g. CD-ROM and DVD devices, ZIP
drives, tape drives, SCSI pass-through, etc.)
uaehf.device uses IOCTL functionality (see
below), and does not require SPTI or ASPI. It provides limited
emulation of SCSI commands, e.g. for HDToolBox and similar system tools, for mounting devices and for booting from them,
and to support file systems and partitions, in a way similar to
the boot ROMs that are included with Amiga SCSI controllers.
uaescsi.device uses either SPTI (Windows 2000, Windows XP and
higher) or ASPI functionality (Windows 98 and Windows Me),
depending on the version of Windows and the installed software (see
below).
Because the emulation needs to merge and support units from
different access interfaces, SCSI ID (unit) numbers inside the
Amiga environment have no relationship with "real" device ID or
unit numbers. In particular, uaescsi.device
unit numbers 0 and 1 are reserved (and automatically remapped, if
necessary) to the first two CD-ROM/DVD type devices.
Other Amiga SCSI Devices
With the Amiga 3000, Commodore introduced a real SCSI disk system and "scsi.device"
support file. When the Amiga 4000 was released (with IDE only, no SCSI),
Commodore opted to keep the "scsi.device" name for the support file, and modify
the functionality, to allow booting from IDE media and keep using the same
tools (such as HDToolBox) that already had "scsi.device" in their ToolTypes and
other settings. Also, the IDE variant of Commodore's scsi.device included
limited SCSI emulation, which was enough for some programs to work (in a way
similar to uaehf.device), and to extend the capacity of IDE support to about 8
GB (if the file system had direct SCSI support, such as SPS and SFS) at times
when a 4 GB limit was common. This can be confusing because Commodore had two
different device files, both named "scsi.device", but one being a full SCSI
implementation, and the other an IDE variant.
Amiga Forever does not include the IDE
version of the Amiga scsi.device in its
3.X Workbench ROM, and
cannot boot from Amiga-formatted legacy IDE
devices. However, these disks can be mounted
after booting as described in this document,
and Amiga Forever can boot from an image
file of the same disk.
Emulation Settings
If you determine that you need to use uaescsi.device:
- Make sure that the "uaescsi.device" option is enabled
in the WinUAE settings.
Furthermore, if you are using a non-disk, non-CD device, keep
in mind that:
- If SPTI functionality is not available on Windows, the "Use ASPI SCSI layer" WinUAE option must be set
(otherwise only hard disks and CD/DVD drives are supported);
- By default, uaescsi.device as implemented in WinUAE up
to version 1.0 does not automatically mount
all types of devices. For example, it will mount a CD drive,
but it will not mount a scanner. If your device does not
appear to be recognized, then you must force-enable
detection of all SCSI devices by using the "-noaspifiltering"
WinUAE command line option. This is not necessary in WinUAE
1.1 and higher.
As a general rule, in order to avoid accidental access and
corruption of non-Amiga data, the emulation (WinUAE) will only
mount
disks that are recognized as either being empty or having Amiga-formatted content.
This means that by default it is not possible to mount
PC-formatted disks, or disks formatted under custom Amiga
partition schemes, such as those developed before the release of
the Amiga Rigid Disk Block specification, or RDB/RDSK. This
behavior can be overridden by starting WinUAE.exe with the -disableharddrivesafetytest
command line option. If the drives have a PC file system (e.g.
FAT or NTFS) they can also be mounted as mapped drives
or directories in the emulation, provided that they are
accessible by the Windows side.
Amiga Settings
All Amiga programs that support SCSI peripherals have one ore
more configuration parameters (ToolType, command line option,
etc.) that need to be set to the proper device name and unit
number. So be sure to set the correct device name
("uaehf.device" or "uaescsi.device") and unit number.
Within the Workbench 3.X environment of Amiga Forever you can
use the "FindDevice" tool (in "Work:Software/IDEfix97") to
verify that a device has been recognized, and to obtain the unit
number as it has been mapped within the emulation environment.
The WinUAE log file, if enabled, also lists the unit numbers
that have been assigned to recognized devices.
Windows IOCTL Support
The virtual uaehf.device device which is part of the Amiga emulation uses the
Windows IOCTL (I/O Control Code) software interface to provide
access to devices. IOCTL is supported on Windows 2000, Windows
XP, Windows Server 2003, Windows Vista, Windows 7 and Windows Server 2008. It only supports block-type devices
like hard disks, including USB storage media, flash memory
disks, etc.
As a rule of thumb, if Windows detects such a device and
allows you to configure it in Disk Management (found under
Storage, in Computer Management), WinUAE can use it via
uaehf.device.
This functionality requires administrator privileges.
Windows SPTI and ASPI Support
The virtual uaescsi.device device which is part of the Amiga emulation uses
either the Windows SPTI (SCSI Pass Through Interface) or the
Windows ASPI (Advanced SCSI Programming
Interface) software interface to provide access to devices. ASPI is included by Microsoft in
Windows 95, Windows 98, and Windows Me. ASPI is not directly
supported by Microsoft on Windows NT and newer versions of
Windows, where it has been replaced by the newer SPTI. In order to maintain compatibility with
different versions of Windows the Amiga emulation software can
use either SPTI or ASPI.
In order to use ASPI on Windows 2000, Windows XP, Windows
Server 2003, Windows Vista, Windows 7 and Windows Server 2008 you may need to install a third-party ASPI
component. This software is made available (often for free
download, or as part of evaluation versions of their software)
by companies like
Nero
and
Adaptec. If you have a recordable CD or DVD writer mounted in your
system then you most likely already have such software
installed.
It has been reported that the software by
Nero
is more compatible than the one by
Adaptec when used with CD-like devices and hard drives.
Apparently however the Nero software may not support certain
other devices, such as scanners.
In WinUAE 1.0 and higher, the ASPI software is
detected automatically. In previous versions of WinUAE you may
need to copy the ASPI DLL file (e.g. "wnaspi.dll") to the WinUAE
program directory. SPTI is only supported in WinUAE 1.1.1 and
higher.
Another Approach: Using Disk Images
Software like
WinImage (on Windows) can
be used to create a low-level image of any disk. This image can
then in turn be mounted by the emulation as a hardfile (set the
Surfaces, Reserved and Sectors settings to 0). This procedure
supports different types of media (hard disks, ZIP, etc.), and
does not require that the host operating system have an Amiga
file system.
We have seen cases of Amiga partitions transferred by
WinImage where the high and low bytes were swapped (e.g. the
"RDSK" header had become "DRKS"). This can be corrected with a
good hex editor, after which the partitions can be mounted by
WinUAE.
Windows 2000: Details about Limited Functionality
Under Windows 2000 WinUAE has limited access to the exact
hard disk configuration. In particular, it can only get generic
information about the hard drive geometry, which is usually not
enough to calculate the total disk size up to the exact end of
the disk. This means that when reading Amiga disk partitions
formatted using the FFS or OFS file systems some errors may
occur when reading or writing the last few blocks. Similarly,
partitions formatted using the SFS file system cannot be mounted
at all, because SFS places crucial information in the last block
of a partition.
Beginning with version 0.9.92 WinUAE started supporting the
new IOCTL_DISK_GET_LENGTH_INFO functionality first introduced in
Windows XP, and also available in Windows Server 2003,
Windows Vista, Windows 7 and Windows Server 2008, which makes it possible to
obtain the exact disk size, overcoming the above limitations.
If you need to transfer partition data from the Amiga to a
Windows 2000 PC you can consider using Amiga
Explorer.
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