
Since the Mac uses ONLY SCSI-1 for hard drives YES the "figure includes a
hundred $$$ for SCSI drivers"  This is sloppy people and DUMB.

Ok once again with the SCSI spec list:
SCSI-1 {with a SCSI-1 controler chip} synchronous range is indeed 0-5MB/s
 asynchronous range is slower at 0-3MB/s.
SCSI-1 {With a SCSI-2 controller chip}: 4-6MB/s with 10MB/s burst {8-bit}
 Note the INCREASE in SPEED, the Mac Quadra uses this version of SCSI-1
 so it DOES exist. Some PCs use this set up too.

SCSI-2 {8-bit/SCSI-1 mode}:          4-6MB/s with 10MB/s burst
{for those who want SCSI-2 but don't want to pay for the 16-bit or 32-bit
 hardware or mess with the SCSI-2 software controllers.  Usable by SCSI-1
 devices with close to 8-bit SCSI-2 speeds}
SCSI-2 {16-bit/wide or fast mode}:  8-12MB/s with 20MB/s burst
SCSI-2 {32-bit/wide AND fast}:     15-20MB/s with 40MB/s burst

On the other interfaces let DXB132@psuvm.psu.edu speak:
Again synchronous and asynchronous modes with asynchronous much slower
 {Range 0-5MB/s}

One problem is the inconsitant use of the term 'SCSI' in articles and by
people.  Its PROPER meaning is "The set of SCSI interfaces composed of
SCSI-1 AND SCSI-2"
Look at the inconsitant use of SCSI in the below quote:
(My comments in {})

PC Magazine April 27, 1993:29 "Although SCSI is twice as fast as ESDI,
{This is asynchronous SCSI-1 with a SCSI-1 chip} 20% faster than IDE..."
{this is BOTH asynchronous SCSI-1 with a SCSI-2 chip AND 8-bit SCSI-2}
To read CONSITANTLY the quote SHOULD read:
{asynchronous SCSI-1 with a SCSI-1 chip}
"Although asynchronous SCSI-1 is twice as fast as ESDI, one third the 
speed of IDE..."
or {asynchronous SCSI-1 with a SCSI-2 chip or 8-bit SCSI-2}
"Although SCSI-1 with a SCSI-2 chip and 8-bit SCSI-2 are eight times as fast as
ESDI, 20% faster than IDE..."

NOTE the NONUSE of 'SCSI' by itself.  This eliminates ambaguity.

SCSI-1 drivers are somewhat reasonable while 16-bit and 32-bit SCSI-2 drivers 
are VERY expansive {8-bit SCSI-2 can use SCSI-1 drivers with little speed
degridation(the Mac Quadra does EXACTLY this.)}