View Full Version : general questions on ports. seperate logic or not?

Cox Orange
Jul 22, 2011, 04:46 PM
I guess my question is a bit problemativ, cause "ports on PowerPC Macs" includes so many different motherboards, with different design.

I wondered, if all ports on PowerPC Macs are seperate (if you know what I mean).

Some one some time ago told me, that he has low speeds on his powerbook using the USB ports simultaneously, because they were on the same controller.

I am not by anyway really into the technology part of Computers (that go above the knowledge of parts).

What I am assuming is, that there should be ports that are somehow seperate and can get data in at one time and give it out through the other with less delay, while other Motherboard designs seem to feature ports that somehow buffer the data and then give it out through the other port. Does this make any sense?

Sorry for my wired question, maybe someone understands what I am puzzled about.

My question would be, which PPC-Models had ports that had a seperate logic?

Jul 22, 2011, 04:49 PM
I guess you can see it in system profiler...

Jul 22, 2011, 08:45 PM
All desktop computers have their ports soldered to the Logic Board, except for front-panel connectors or expansion cards on PCI/PCI-E slots.

Some laptops are the same way, some have daughterboards with ports.

Jul 23, 2011, 12:19 AM
I think I understand the question, and it's taken me 3 beers to actually get to this point. For some reason it made no sense earlier! :D

The OP is asking if, for example, there are 2 USB ports.... if there is a Mac that has each port on a separate USB controller....I think. (I've never heard of a single port having it's own chip, but... discuss)

I always thought each port would get a dedicated 11mbps line to it, with no slowdowns if using each port simultaneously, but I'm willing to be enlightened if this is incorrect.

Jul 23, 2011, 12:40 AM
Mostly I use the system profiler as reference, if the port has a dedicated address then it has its own individual controller chip.

Cox Orange
Jul 23, 2011, 04:51 AM
Thanks for all the answers to such a somehow stupid question, I am glad you didn't rip of my head :)

About the desktops all having ports soldered: the b&w G3 has a firewire daughtercard :-)

I have an example from the 24" Intel iMac (well I was not asking about Intels, but...) that had 1 Firewire400 and 1 firewire800. If users used both ports the firewire800 port would work at maximum with the speed of firewire400.

Now, I watched systemprofiler, like Nameci suggested, my iMac G3 shows 2 seperate USB ports, with detailed info, one has "Bus-number" 018 and the other 019. The 2 firewire ports are shown as "firewire-bus" no additional info, only the info that it supports up to 400mbit/s.
When I connect two firewire devices, it shows both devices under one firewire entry in the profiler. The USB ports are shown as two separate entries.

PS: under OS 9's systemprofiler, you can clearly see, that the USB-ports are shown as separate branches and firewire is written on one branch.
Like this:

-USB-A------- device mouse
-USB-B------- device keyboard------USB,USB

-Firewire------- Device1, Device2

Jul 23, 2011, 08:58 AM
I do remember reading somewhere that when you have FireWire devices daisy-chained together, their bandwidth is shared.

If a logic board has one FW controller, 2 ports, and you have a device connected to each port, does that count as daisy-chaining?

Wonder if Thunderbolt is the same way........

Jul 23, 2011, 09:05 AM
The two USB port have two specific addresses and two specific controllers, the FW has only one controller that has a max throughput of 800bmps... I believe.

Jul 23, 2011, 09:07 AM
and 400mbps per channel.

Jul 23, 2011, 09:10 AM
Sharing bandwidth?

I believe since protocol is serial?