For the IEEE 1394 FireWire interface, what are the typical maximum data rate and maximum number of devices that can be connected on a single FireWire bus?

Introduction / Context:
FireWire, also known as IEEE 1394, is a high speed serial bus standard that was widely used for connecting digital video cameras, external storage, and other multimedia devices. Understanding its basic specifications is important for hardware and system designers as well as for exam preparation. Two key parameters are the maximum data transfer rate and the maximum number of devices that can share a single FireWire bus segment.

Given Data / Assumptions:

• We are referring to the common IEEE 1394a FireWire implementation, often labeled as FireWire 400.
• FireWire supports a tree topology with multiple devices connected on one bus.
• The bus uses a 64 device addressing space, of which one address is used by the host, leaving a smaller number for peripherals.
• We are concerned with typical exam level specifications rather than every later variant.

Concept / Approach:
IEEE 1394a, also called FireWire 400, supports data rates up to 400 megabits per second. The addressing scheme allows up to 64 nodes on a bus, including the host. In practice, this means up to 63 peripheral devices can be connected to a single FireWire bus. These numbers are often quoted in hardware documentation and are standard reference values for FireWire 400. Later versions such as IEEE 1394b introduced higher speeds, but 400 megabits per second and 63 devices remain the canonical figures for the original common standard.

Step-by-Step Solution:
Step 1: Recall that FireWire 400 indicates a maximum nominal data rate of 400 megabits per second.Step 2: Remember that the FireWire addressing model allows 64 addresses on a bus, one of which is used by the host controller.Step 3: Subtract the host node from the total, leaving up to 63 addressable devices on the bus.Step 4: Compare these values with the options to find the one that states 400 megabits per second and 63 devices.Step 5: Select the option that matches these standard FireWire 400 specifications.

Verification / Alternative check:
You can verify these numbers by considering typical external hard drives and digital video camcorders that used FireWire 400 ports. Documentation and marketing materials usually mention a transfer rate of up to 400 megabits per second and support for daisy chaining multiple devices. The bus based design allows many devices to share the same cable path through hubs or daisy chain connections, which relates to the maximum device count. These real world uses reinforce the theoretical specifications.

Why Other Options Are Wrong:
Option B is wrong because 10 megabits per second and 16 devices resemble older Ethernet or other bus limits, not FireWire capabilities. Option C is incorrect as it claims an unlimited number of devices and a 1 gigabit per second rate, which does not match FireWire 400 and ignores bus addressing limits. Option D is also incorrect, as 100 megabits per second and only 4 devices would significantly understate FireWire performance and capacity.

Common Pitfalls:
One common confusion is mixing up FireWire specifications with those of USB or Ethernet. For example, USB uses different topologies and device limits, and Ethernet data rates follow other standards. Another pitfall is to assume that later IEEE 1394b speeds apply to all FireWire questions, while exam questions often focus on the original FireWire 400 standard. Keeping the key numbers 400 megabits per second and up to 63 devices in mind helps answer questions accurately.

Final Answer:
The typical FireWire 400 specification supports up to 400 megabits per second with up to 63 devices on a single FireWire bus, which matches option A.