Requiem For Floppy Disk, CD And DVD Storage
Mobility with USB 2.0, FireWire and Serial ATA
For a long time the 1.44 MB floppy disk was the preferred medium when you wanted to transfer a Word or Excel file from one PC to another. But with growing file sizes, this medium is quickly overstretched. Its successor, the CD, is also easily filled these days. In the age of DSL, P2P file sharing, MP3 and DivX, even the 4.7 or 8.4 GB of capacity that a DVD offers is only a temporary solution.
However, internal 160 GB, 200 GB and 300 GB hard drives are now available at affordable prices. Combining a hard disk with an enclosure or an adapter to back up data to a PC can be done for less than $20. For example, it's now possible to combine a 160 GB Samsung hard drive and an adaptor or enclosure for a total cost of $100. Connection options include USB 2.0, FireWire and even Serial ATA.
However, IEEE1394, also known as Apple's FireWire or Sony's i.Link, is less common. Serial ATA also causes problems in external operation. Although in widespread use, it is mostly used within the PC enclosure and seldom found outside it.
Bandwidths Of Various Interfaces
|Interface||Theoretical Bandwidth||Practical Bandwidth|
|USB 1.1 (alt)||12 MBit/s||1 MByte/s|
|USB 2.0||480 MBit/s||25 MByte/s|
|IEEE 1394A / Firewire400 / i.Link||400 MBit/s||30 MByte/s|
|IEEE 1394B / Firewire800 / i.Link||800 MBit/s||60 MByte/s|
|Serial ATA||1500 MBit/s||120 MByte/s|
A fixed factor between MBit/s and MByte/s is impossible to calculate as every transmission control protocol handles error correction differently. The practical bandwidths are averages and may vary from manufacturer to manufacturer (overheads vary).
This table shows that the interface very often becomes a bottleneck for the hard drive. In generally, standard modern hard drives reach 35 MByte/s, top of the range models up to 60.