I'm looking for good USB powered hard drive 250 gigs. Something that runs off the USB power, and I can bring with me and take with my laptop. I have a iBook G4.
Hard drives come in three flavors: 3.5 inch, 2.5 inch, and 1.8 inch (you could also count microdrives I guess).
3.5 inch drives are the drives that are in desktop computers. They are large and bulky to be carrying around for travel. These drives have larger power requirements and external cases require an AC adaptor or just a power cord to plug into the wall (meaning the AC adapter is inside the case). You'll never power these off a FireWire or USB1.1/2.0 connection. I think that the apex of capacity on these is 400GB or 500GB right now.
2.5 inch drives are laptop drives. Most laptops use this size of drive and most external *and* portable drives are of this size. Right now, due to platter densities, the highest capacity 2.5 inch drives are 120GB or 160GB. And even at that, you'll only get it to power off of the bus (meaning no AC Adapter/power cord) if the drive has power requirements that fit within the amount of power the bus provides.
FireWire provide something like 1.5 Amperes. USB2.0 provides .5 Amperes. A 100GB drive I got over the summer needs 1 Ampere to spin up the disk (the initial spin up). At the time, I did a lot of looking around and IIRC, only *some* of the 80GB drives were under 1 Ampere (even then it was like .8 or .9).
1.8 inch drives are smaller drives. They are put to use in things like iPods and ultra thin PC laptops. They obviously have a smaller maximum capacity than the 2.5" drives, and I'm too lazy to even attempt to look it up.
This all boils down to a couple of things:
1) Any drive over 40GB (or maybe 60GB) will require either:
- 1 6pin FireWire connector
*OR*
- 2 USB2.0 ports (it will only use one of the ports for power, so you're not going to see any speed boost)
That is, if you want it to be powered completely off of the USB/FireWire cord.
2) You're not going to find a 250GB drive that will be powered off of the bus.
3) If you do get an external 250GB drive, it will not be as portable as you are probably aiming for.
Comments
3.5 inch drives are the drives that are in desktop computers. They are large and bulky to be carrying around for travel. These drives have larger power requirements and external cases require an AC adaptor or just a power cord to plug into the wall (meaning the AC adapter is inside the case). You'll never power these off a FireWire or USB1.1/2.0 connection. I think that the apex of capacity on these is 400GB or 500GB right now.
2.5 inch drives are laptop drives. Most laptops use this size of drive and most external *and* portable drives are of this size. Right now, due to platter densities, the highest capacity 2.5 inch drives are 120GB or 160GB. And even at that, you'll only get it to power off of the bus (meaning no AC Adapter/power cord) if the drive has power requirements that fit within the amount of power the bus provides.
FireWire provide something like 1.5 Amperes. USB2.0 provides .5 Amperes. A 100GB drive I got over the summer needs 1 Ampere to spin up the disk (the initial spin up). At the time, I did a lot of looking around and IIRC, only *some* of the 80GB drives were under 1 Ampere (even then it was like .8 or .9).
1.8 inch drives are smaller drives. They are put to use in things like iPods and ultra thin PC laptops. They obviously have a smaller maximum capacity than the 2.5" drives, and I'm too lazy to even attempt to look it up.
This all boils down to a couple of things:
1) Any drive over 40GB (or maybe 60GB) will require either:
- 1 6pin FireWire connector
*OR*
- 2 USB2.0 ports (it will only use one of the ports for power, so you're not going to see any speed boost)
That is, if you want it to be powered completely off of the USB/FireWire cord.
2) You're not going to find a 250GB drive that will be powered off of the bus.
3) If you do get an external 250GB drive, it will not be as portable as you are probably aiming for.