Ben Apple of Mac Junkie
wrote an interesting article, G4's
concealed FireWire port: The possibilities are intriguing. It was
the first I'd heard of an internal FireWire port on the Power Mac
G4/450 and G4/500.
Ben's question and mine: why?
Apple obviously feels there will be a demand for FireWire devices
inside the box - and within the life span of the Sawtooth
motherboard.
The faster G4s already support Ultra DMA/66 drives, which are wicked
fast. But they suffer a failing of all IDE-style drives, they require
more CPU control than SCSI drives, which means system performance is
slightly reduced during drive access.
Another drawback of IDE is that each connector can only manage two
drives, a master and a slave. It's not as extensible as SCSI, USB, or
FireWire.
FireWire is essentially a very fast serial version of SCSI (see
FireWire a Form of SCSI by Alex
Timbol). It supports 63 devices, has a bandwidth of 400 Mbps (32 times
faster than USB), is hot swappable like USB, and supplies up to 60W of
power to FireWire devices.
And, because it's related to SCSI, it requires less CPU control than
the IDE family of interfaces.
So by building a internal FireWire port into the Sawtooth
motherboard, Apple makes it possible to add additional internal high
speed drives without using IDE slave mode (which is slower than master
mode) or adding a SCSI or IDE card.
For many users, that alone will save one expansion slot.
It also simplifies internal expansion. Instead of unwieldy ribbon
cables and power cables, a single FireWire cable will move data and
supply power to internal drives. It's much more elegant than the older
SCSI and IDE protocols with their multiple parallel data lines.
Beyond that, Apple has demonstrated bootable FireWire as a
technology demonstration. I don't know if this will be a standard
feature of the Sawtooth ROMs, but it could always be added in the
future. (The Power Mac G4 is the first Mac to support bootable USB.
Nothing on Apple's site confirms or denies the ability to boot the G4
with a FireWire device.)
Of course, for Apple to switch to FireWire as its standard drive
interface, prices have to come down a lot.
Enter the Next iMac
From my perspective, expanding the FireWire market rapidly is the
best argument for Apple building FireWire into the next iMac. Just as
last year's iMac drove acceptance of USB, putting FireWire on a
consumer computer will nudge the peripherals industry to create more
FireWire drives - hard drives, tape drives, removable media drives,
etc.
Further, the expanded market will drive prices down.
As already covered in The Truth About
USB Speed, USB simply doesn't cut it for hard drives. It's adequate
for Zip and Imation drives, but seriously limits the performance of
hard drives.
FireWire can solve that problem today.
What about USB 2?
There's a move afoot to expand USB to the 240-320 Mbps range, but
the standard has not yet been finalized.
The time is now for Apple to push FireWire, establishing it as the
standard high speed bus before USB 2 is available.
And once they do that, the market will grow to the point where it
makes economical sense to replace the Ultra ATA boot drive in the Power
Mac G4 with a bootable FireWire drive.
And that's undoubtedly a leading reason Apple put an internal
FireWire port on the Sawtooth motherboard.
