Creative engineers and product designers are constantly coming up with new ideas for interesting products. One company with plenty of inventive folk is Taiwan-based Upgradeware, which in the past made the news mostly because of its processor upgrades.
Their latest offering is a pair of PCI cards, the HD25I and HD25IS, which are adapters that make it possible to install a 2.5" hard disk in a conventional desktop PCI slot. Upgradeware doesn't put an extra hard disk controller on the board. Rather, it uses the PCI slot only as a location and energy source for the installation of the hard disk. The interface continues to be through the PC motherboard.
Installing a 2.5" hard disk in a desktop PC almost always requires an adapter. This is because not only are the connecting contacts for 2.5" hard disks smaller than the pins for normal 3.5" desktop models, the drive's power is also supplied by the connectors. This is contrast to 3.5" drives, which depend on a conventional Molex plug for power.
The question remains, however: why does anyone actually need this adapter? Upgradeware quotes prices of $25 for the UltraATA variation and $35 for the version with a converter so the hard disk can be used on an SATA system. (2.5" hard disks with an SATA interface are not supported.) As a result, both versions are more expensive than corresponding 3.5" and 2.5" adapters.
One possible reason for using this device is to install an already available 2.5" UltraATA hard disk in a PC that doesn't have any ATA ports free, or one that only lets the drive be used as a slave, which isn't an option with notebook drives. The PCI adapter cards can also let you take advantage of available space for installing another hard disk if the system case has no more space for drives. After all, almost every user has at least one or two free PCI slots. Another application would be a mini-barebones computer, which doesn't offer the user any other option for installing an additional hard disk.
This is not an entirely new idea. In the mid-1980s, Plus had its HardCard, a 10 MB hard disk on an ISA slot for the first generation of PCs.