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Help with External Hard Drive

Patricio Elicer

Obsessed with Reality
Patricio Elicer
Joined
Aug 6, 2001
Messages
4,633
Location
Santiago, Chile
As I was rapidly running out of memory I decided to buy an external hard drive. External, mainly because of ease of installation, just plug and play (on USB port).

It is advertised as "up to 480 MB/s transfer speed". So I thought it was good for digital video capturing storage. But it is not, capturing digital video to the unit ends up in a totally screwed video file. Also, a 200 MB file takes about 5 minutes to transfer.

So what's wrong?. I'm not willing to blame the seller at this point, it's likely my computer limitations. But what limitations?. I'm on a 1.6 GHz Pentium IV, 512 MB RAM. Can it be the USB speed?. How can I know what type of USB I have, USB1.1 or USB2.0?
 
Patricio Elicer said:
It is advertised as "up to 480 MB/s transfer speed". So I thought it was good for digital video capturing storage. But it is not, capturing digital video to the unit ends up in a totally screwed video file. Also, a 200 MB file takes about 5 minutes to transfer.
Click to expand...


Check whether the data transfer speed is stated in megabits per second (small 'b') or megabytes per second (capital 'B'). I would think that it says the former.
 
ohms said:
Check whether the data transfer speed is stated in megabits per second (small 'b') or megabytes per second (capital 'B'). I would think that it says the former.
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Not clear. It is listed as both mb/sec and MBPS.

I'm a computer illiterate, but on further thought: Isn't 480 MB/sec excessive?. I mean it's 60% the capacity of a CD-R, in 1 second?

This is the unit:

http://cgi.ebay.com/60GB-External-H...715857877QQcategoryZ41911QQrdZ1QQcmdZViewItem

Thanks for your reply.
 
480 Mbps is the maximum rate at which USB2 can operate. It is BITS per second, not bytes. Simple rule of thumb is to divide by 10 to get the bytes per second (I know it's really 8 but 10 makes the maths easier). So that makes around 50 MB per second at its maximum theoretical speed.

Oh yeah, you will never get the theoretical max because of a number of other factors. (file type, no of files, other hardware bottlenecks)

It's the same with ordinary hard drives - my internal drive is listed as 100MB per second but benchmark tests rarely get above 20 or 30.

For video work I find that firewire hard drives 'seem' quicker than USB2 even though they max out at 400Mbps. Might be purely subjective though.
 
Oleron said:
480 Mbps is the maximum rate at which USB2 can operate. It is BITS per second, not bytes. Simple rule of thumb is to divide by 10 to get the bytes per second (I know it's really 8 but 10 makes the maths easier). So that makes around 50 MB per second at its maximum theoretical speed..
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Ah, but even if the "actual" transfer speed is, say, 10 MB/sec, it should take 20 seconds to transfer a 200 MB file. But it took several minutes, perhaps up to 5.

I'm purchasing a FireWire "combo" card with 4 USB2 ports and 2 ports for capturing digital video. I hope this will solve my speed problem. But I'm still unclear on whether or not the USB's are powered. Anyone?
 
I just bought a PCMCIA USB card for my laptop, and it can be either internally or externally powered. The instructions said that if you were trying to run something large, say a printer, from the card, then the external power source should be used.

Stupid iPods no longer use firewire, only USB 2.0
 
Lisa Simpson said:
The instructions said that if you were trying to run something large, say a printer, from the card, then the external power source should be used.
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My external hard drive has no plug for external power, it only operates with the USB power. So if the firewire USB's are not powered, I'm still in trouble.

Thanks for your tip, Lisa :).
 
My first thought would be to return it and get an internal hard drive which is cheaper and really quite easy to install. Although there might be good reasons for external.

I would maybe work around it by copying a bunch of files from your computer's drive to the external thereby opening up a large space on your internal drive. Capture your video there and then copy it to your external drive. Clumsy, yes.

You might be able to find out if which USB system you have through My Computer - Properties. You can also buy USB 2.0 cards. An internal drive will still be much faster.
 
jimlintott said:
My first thought would be to return it and get an internal hard drive which is cheaper and really quite easy to install. Although there might be good reasons for external.
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I chose external mainly for ease of installation, in general I'm not prone to intervene the guts of my computer. Also because it's portable, it works as a giant pendrive.

I would maybe work around it by copying a bunch of files from your computer's drive to the external thereby opening up a large space on your internal drive. Capture your video there and then copy it to your external drive. Clumsy, yes.
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Yes, that's what I pretend to do. Capturing digital video to my internal is OK.

You might be able to find out if which USB system you have through My Computer - Properties. You can also buy USB 2.0 cards. An internal drive will still be much faster.
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I've tried that, but the USB specifications are nowhere to be found.
 
Patricio Elicer said:
Ah, but even if the "actual" transfer speed is, say, 10 MB/sec, it should take 20 seconds to transfer a 200 MB file. But it took several minutes, perhaps up to 5.

I'm purchasing a FireWire "combo" card with 4 USB2 ports and 2 ports for capturing digital video. I hope this will solve my speed problem. But I'm still unclear on whether or not the USB's are powered. Anyone?
Click to expand...

If it is taking that long then the chances are that your PC has USB1 ports on it - Max transfer rate of 12Mbps (around 1.5MB persecond). Even of the hard drive is USB2 compatible it will be speed-limited by the PC's own ports.

That's why I always liked firewire - you know what you're gonna get with it.
 
Couple of points, and using explicit units -
First, with a 1.6GHz P4, on average, you've probably got USB1. Which explains everything. The USB2 on the combo card you're talking about getting will be fine.
If the external hard drive is actually a desktop drive in a caddy, and using USB2 or firewire, expect a max of (on average) 50 megabytes/sec transfer rates. If it's based on a laptop (2.5") hard drive (which is about the size of a packet of 20 cigarettes only slimmer) then expect a max of about 25 megabytes/sec transfer.

The 480Mb/sec quoted by the seller is just the maximum USB2 throughput, and nothing to do with what the device can or cannot actually handle. It's at best misleading, and at worst an outright lie to attribute it to any particular device.

As far as power goes, the USB spec *requires* *each* usb port to provide 5v @ 500mA. If a USB device needs more than this, then it will come with a power socket, and if you use it without one, then XP (I'm assuming you're using Windows XP) will complain when you plug it in. Underpowered external hard drives typically don't work at all, and constantly click as they reset themselves.

Some motherboard manufacturers are better than others at keeping to their tolerances. In other words, some are complete garbage. It's a bit pot luck.

One other thing to make sure (again assuming Windows XP) of is that you're running Service Pack 2. Because USB2 support was nonexistant before that!

HTH
 
moopet said:
First, with a 1.6GHz P4, on average, you've probably got USB1. Which explains everything. The USB2 on the combo card you're talking about getting will be fine.
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Yes, I'm hoping so.

But...

One other thing to make sure (again assuming Windows XP) of is that you're running Service Pack 2. Because USB2 support was nonexistant before that!
Click to expand...
Nope, I'm on Win 2000 :(

I'm expecting to get the combo card in 1 week or so. We'll see what happens.

Thanks for the tips.
 
You can check of it is USB 1 or 2 in the BIOS when you start up your system.

If you don't have USB 2(you probabily don't) you can buy a 4 port PCI USB2 card for about $25.

And USB2 2 support was included in SP1 of XP, Not XP2.
 
I have two external hard drives for backup (300GiB each), and that does sound a little slow, so I would go with your having USB1.1. I can usually do a full backup on mine in less than that, albeit an incremental one.

One thing I find is that an on-access virus scanner slows this sort of transfer down beyond belief. Not a problem for me at home, but at work I always suspend the virus scanner while doing transfers of large files, or lots of small files.

Cheers,
Rat.
 
Patricio...

Goto

Control Panel / System / Hardware / Device Manager / Universal Serial Bus Controllers

Click on that and look down the list...If you see the word 'Enhanced' on any entry...you can run USB 2.0

DB
 
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