Functionality of USB HDD's

[Pegesus]

I'm toying with the idea of using portable USB HDD's on a new system build im working on. Has anyone used them for their main OS drive. Do they lose some speed transfers or what not. I'm hoping they run just as well as an internal drive aesthically it will be better for my design.

 

[Dangman]

I'm toying with the idea of using portable USB HDD's on a new system build im working on. Has anyone used them for their main OS drive. Do they lose some speed transfers or what not. I'm hoping they run just as well as an internal drive aesthically it will be better for my design.

There is a substantial performance loss if you boot from an external hard drive.

Quick question - what is your design?

 

[Pegesus]

Not exactly sure of the complete desing yet. But it will be along the lines of a SFF but modeled after an old antique chest i have. Once i get the design created i'll be posting a worklog for it.

 

[Ignad]

not knowing what exactly you have in mind...

but consider using e-sata.


More or less similar sized small cable as usb... but no speed loss.


http://en.wikipedia.org/wiki/SATA#External_SATA

 

[Whatsisname]

with USB, it would run very slow compared to a proper hard drive interface. You can however have external drives run with a SATA interface, which would be fine.

 

[zero_vertical]

where SATA is hot swappable, and 3.0Gig/Sec, what does USB offer that SATA doesn't?

i'd grab an internal SATA HDD, get an external case for it, and have a SATA port wired to a convenient spot on the case.

zv

 

[kick]

If size is the issue, what about using a 7200RPM notebook drive?

 

[CairnGorm]

USB is barely passable for large backups...as a OS drive I would strongly urge you to reconsider.

 

[ChingChang]

Maybe you should do it with eSATA... 3Gbps max speed compared to USB 480Mbps...

I have three of these enclosures. Best ones I have used. Great build quality and design. It can do USB or eSATA.
Also available in black.

 

[drizzt81]

3Gbps max speed compared to USB 480Mbps...

I believe it is important to note that the widely publicized 480Mbps figure for USB2 does not apply to the type of transfer that is required for data storage. Streaming devices like webcams and similar do not care about bit errors or lost frames, therefore they can utilize a transfer mode (isochronous) on USB2 that is very simple, very fast, but has neither delivery confirmation nor data integrity protection. Block devices, where people would like to retrieve their data at a latter point require a different transfer mode, called interrupt or bulk, which does not occur as quickly (or as frequently) as the isochronous transfer. If my memory serves me correct there is a theoretical limitation on the data rate achievable in this way that comes out to close to 24MiB/s for uncompressed data.

 

[zero_vertical]

I believe it is important to note that the widely publicized 480Mbps figure for USB2 does not apply to the type of transfer that is required for data storage. Streaming devices like webcams and similar do not care about bit errors or lost frames, therefore they can utilize a transfer mode (isochronous) on USB2 that is very simple, very fast, but has neither delivery confirmation nor data integrity protection. Block devices, where people would like to retrieve their data at a latter point require a different transfer mode, called interrupt or bulk, which does not occur as quickly (or as frequently) as the isochronous transfer. If my memory serves me correct there is a theoretical limitation on the data rate achievable in this way that comes out to close to 24MiB/s for uncompressed data.

very informative. Thanks! This place rocks.

zv