🚀 go-pugleaf

In article <1998020808385021123@teknesis.demon.co.uk>,
LPS@teknesis.demon.co.uk (Larry Stoter) wrote:

> Allan Reynolds <allan@phantech.co.uk> wrote:
> 
> > I am looking to add some stuff to me SE/30 but I am quite new to Macs and I
> > am unsure if I am able to just connect any SCSI device or if it has to be
> > specific to the Mac?
> > I am looking at adding an extra HD and a CD-ROM external of course.  I also
> > have a SCSI scanner which when connected to the Mac is identified and I have
> > the drivers for it from the WWW but I dont have any software to try it and I
> > was wondering if anyone knew of any free scanning software for the mac?
> > 
> > Allan
> 
> In principle you should be able to connect any SCSI device. However,
> some more recent SCSI devices will, I believe, be SCSI II which I doubt
> will be compatible with the SE/30.

SCSI II equipment is fully compatible with the SE/30. *WIDE* scsi devices
are not, nor are *DIFFERENTIAL* SCSI devices.

> Of course, you will also need the appropriate Mac drivers for the
> device.

This is completely correct. Get FWB's Hard DIsk Toolkit and CD-ROM toolkit
to provide drivers for SCSI hard disk and CD-ROMs respectively.

> Watch for termination problems - some SCSI devices are internally
> terminated, other have no termination. You made need to remove/switch
> off internally terminated devices to get the whole chain working. Only
> the last device should be terminated.

Also completely correct.

> Remember that there is a limit to the number of SCSI devices. I think
> it's 8.

Yes indeed, but this includes the Mac and the internal hard disk. You
can have a maximum of six external SCSI devices.

> Finally addressing - each device must have its own address 0 up to 7.
> The higher the address, the higher the priority, I think - or perhaps
> it's the other way round:) The Mac itself will be address 7. The
> internal HD may or may not be on the SCSI chain - I don't think it is
> with a SE/30.

The addresses have equal priority on the SCSI bus. The only time the
address is significant is on start-up if no start-up disk has been
selected in the StartUp Disk control panel. The Mac then checks the 
scsi devices in order from 6 down to 0.

The internal disk on a Mac will always be 0 (unless someone has foolishly
changed it - use the free SCSIProbe control panel to check).

Paul Durrant