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-   -   Using an external hard drive to capture (https://www.dvinfo.net/forum/open-dv-discussion/697-using-external-hard-drive-capture.html)

Paul Lohr January 15th, 2002 12:47 PM

Using an external hard drive to capture
 
Has anyone had success with an external hard drive such as usb or firewire? I tried capturing to a usb 2.0 hard drive, no dice. Drops too many frames. Have not tried firewire yet. Thanks.

Vic Owen January 15th, 2002 01:04 PM

Funny you should ask.....I recently jumped through many hoops getting an external fw drive to cooperate. I attached a 60GB 7200RPM drive to my MAC -- I got lots of dropped frames, aborts, etc. It worked OK on everything else, but not video.

Turned out not to be a drive problem -- my old B&W G3's built-in firewire ports would only capture at a 3.7MB/sec rate, which is not enough. (Interestingly enough, they captured just fine to the internal IDE and SCSI drives, though.) I solved the issue by adding a Que PCI fw card. I now consistently see 12-13 GB/sec speeds.

I don't believe that USB is fast enough for video capture, but I've never tried it. It's not a drive problem, but rather an interface issue.

Vic

Bill Ravens January 15th, 2002 03:14 PM

I've got a couple of ADS PYRO Drive kits installed on my firewire port and they work great The Drive Kits consist of an external case with cooling fan that mounts a hard drive inside the case. The hard drive can be any IDE hard drive you want, but, obviously the faster HD's will perform better. The kit comes at a reasonable price, $80 on the internet, so you still have to add a hard drive. My system, which uses a 5200 RPM Western Digital ASA66 drive tests out at 25 Mb/sec....well over the required thruput for DV compression. I can connect my DV cam and hard drive kit thru the same firewire card and get really good performance. I haven't tried making these two external drives a RAID zero array...but, I don't really need any extra speed that might buy. I might try that just for grins, tho'. Oh, and these drive kits are hot swappable with another computer.

Rob Lohman January 16th, 2002 02:27 AM

Vic...your probably talking about MB/s and not GB/s... otherwise
i'm wondering how large your harddisk is if you can sustain
that rate and how fast your bus is :))

Bill... are you sure these things are HOT swappable? ie, you can
plug and unplug them WHILE everything is running (your harddisk
and your computer).... this is a very dangerous thing normally
and requires special care to insure there is no data loss or
corruption! Ofcourse if the equipment is off you can always plug
it into another computer. Plugging in is probably hot swappable,
plugging out not I think...

My two $

Vic Owen January 16th, 2002 09:40 AM

Ha! You should see the smoke that comes out of everything, including the cable, when it shifts into the GB/sec mode!

Hot-swapping with firewire works well and is one of its advertised benefits. On a MAC, to dismount, all that is needed is to drag the icon to the trash first. When plugging-in, the fw drive just appears on the desktop.

In fact, until I added the Que fw card, the fw drive would not show up on the desktop until I replugged it. (After installing the new card, it appears OK during boot-up.)

Installing the fw card should keep me a happy camper until Apple "announces" and drops the prices on the existing stuff, or until I just can't stand not having a dp G4 any longer!

Vic

Bill Ravens January 16th, 2002 10:58 AM

On my PC, a small icon appears in my system tray when I plug the firewire drive in. If I click in that icon, I get a window that asks if I want to unplug the device. I click on yes and get a new window which tells me it's safe to unplug. Works great!!

Justin Walter January 16th, 2002 10:13 PM

I have an 80 GB 7200 external firewire drive, I tried capturing directly to the drive once, but nothing happened. However, I am able to capture video to my internal drive and move it over to the firewire drive and work on it from there. I think this is because the read speed is much faster than the write speed. I don't have the exact numbers right now of what you need... maybe someone else does, but if your thinking about buying one, be sure to ask about the read and write speed.

Vic Owen January 16th, 2002 10:41 PM

I can only guess at how you're configured, but keep in mind you cannot capture directly to a fw drive without going through either a computer or an interface device such as the Videonics Firestore.

Most firewire drives are the same as as the IDE drive in your computer -- it's just the interface that is different. The current one you need is the Oxford 911 chipset. Most of the newer external fw drives in cases have that set. R/W speeds should be nearly the same.

I also had a speed problem -- there's a bunch of dialog on some other posts on these boards about that -- it was solved by putting a Que PCI fw card in my MAC, in lieu of the built-in.

You should be able to capture to and read from an external drive successfully. Speed rates might be a little higher for internals due to the bus configuration and speed, but even 5400 RPM fw drives should be able to meet the video requirements.

Vic


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