Q: “How do Glyph’s FireWire drives deal with hot-swapping?”
A: In addition to the FireWire to ATA Bridge chip itself, Glyph bridge circuits incorporate what’s called a “PHY” (physical layer) chip, which translates the OXFW911’s link signals into the signals that travel out the FireWire cable to your computer and other FireWire devices on the bus.
The PHY has a little bit of intelligence of its own, which allows it to signal to the OXFW911 (the FireWire to ATA Bridge processor) when it’s been connected or disconnected from another FireWire device or computer. This capability permits the FireWire devices to be connected or disconnected while power is applied and figure out what’s going on (what’s commonly called hot-plugging or hot-swapping). FireWire PHY chips are designed to be electrically sturdy – after all, they have to take the electrical abuse of being connected while power is applied.
Most hard drives are produced with the common parallel ATA/IDE interface, which was designed for fixed-drive use within a computer chassis. The ATA electrical signals, and the ATA software protocols, were not designed to support connection or disconnection of drives while power is applied. That action, called hot-plugging or hot-swapping, requires special electrical circuits and software, to manage the additional removal of devices, as well as defending against electrical problems when connectors are mated and demated.
