The RaSCSI website provides open hardware and software in order to realize virtual SCSI devices.
The RaSCSI hardware extends the Raspberry Pi with a SCSI interface, so that the Pi can emulate several SCSI devices (hard disk, MO, CD-ROM, network adapter) at the same time. This way one can flexibly add SCSI drives to the Atari.
On the RaSCSI website only the source code for the RaSCSI software is available, but there are no binaries. For users who cannot compile the sources themselves I provide binaries for the FULLSPEC board. The archive contains a development version with numerous extensions and bug fixes I contributed. These improve the compatibility with the SCSI standard and thus also the compatibility with the Atari. Details are provided by the RaSCSI git repository. Most likely these improvements will be part of the next official software release.
The binaries were built with the current 32 bit Raspberry Pi OS, but also work with the current 32 bit version of Ubuntu. 64 bit environments are not supported.
It may be required to add missing libraries to the runtime environment:
sudo apt install -y libpcap0.8
When launching RaSCSI the SCSI IDs to be used and the respective drive image files are specified:
sudo rascsi -ID1 /home/pi/images/scsi_drive_1.hds -ID5 /dev/sda.hds
In this exampe the file scsi_drive_1.hds is installed as hard disk with SCSI ID 1 and the device file /dev/sda as hard disk with SCSI ID 5. The drive type is determined by the extension of the drive image file. For the Atari a standard hard disk with extension hds is recommended. /dev/sda can be a memory card, for instance. CD-ROM images have successfully been tested with the SPIN! driver.
Detailed information, e.g. on launching the software automatically and on the web interface, is provided on the RaSCSI website.
RaSCSI was successfully tested with HDDRIVER 11, a Falcon and a TT, with both the SCSI and ACSI bus. The hardware used were a Raspberry Pi 4B, a Raspberry PI Zero WH and a pre-assembled FULLSPEC board purchased at SamplerSpa. Because TT ACSI is compatible with ST ACSI the board should also work with an ST with SCSI host adapter.
Raspberry PI Zero WH with RaSCSI board connected to a TT
The transfer rate measured with XFERRATE, TT SCSI and a Raspberry Pi 4B is about 1200 KB/s. With a Raspberry Pi Zero WH the transfer rate is about 1100 KB/s. Whether the drive image file is located on an SD card in the Pi's memory card slot or an external USB card reader does not make a difference.
There are no byte swapping issues when exchanging data with other platforms. Thus when partitioning with HDDRUTIL do not enable the respective option.
The screenshot shows HDDRUTIL displaying information on two virtual drives: A hard disk drive with SCSI ID 1 (drive K:) and an MO drive with SCSI ID 5 (drive L:).
With MagiCMac there are also no issues. Via the SCSI Driver for MagiCMac HDDRIVER and HDDRUTIL can directly access SCSI drives and their partitions.