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Writing Native SCSI Disk Drivers for PowerMacs

Q: Is there any information on writing native SCSI disk drivers for the PCI based PowerMacs? Particularly, what's the proper way of installing a native driver on a SCSI disk: is there a special partition type for a native driver, or should there be a standard SCSI disk driver that loads a PowerPC code fragment?

A: Apple doesn't support native SCSI drivers yet (this will be a Copland feature). You can write a native SCSI Interface Module (SIM). Remember that a driver is the software that handles a particular SCSI device, while a SIM is responsible for SCSI controllers (e.g., PCI or NuBus cards).

Normally, SCSI 4.3 drivers are loaded off the Apple_Driver43 partition, and SIMs are typically loaded from the disk controller firmware (PCI card).

If you want to load a native SIM off of the disk, you will have to encapsulate the code fragments, and read and link them in from your standard 68K driver.

See Inside Macintosh: Devices, chapter 4, for more information on loading SCSI drivers.

[Nov 01 1995]

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