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Follow up to earlier posts on download speed.
I wanted to thank Gary and Jan for guidance on speeding up the downloads speeds of my 8gb P2 cards. In the latest batch of testing I did with the help of Eric Escobar, a very smart data centric friend of mine, we were able to significantly reduce the 13-14min download times I was getting earlier.
With a 17″ Powerbook G4 1.67Mhz w/ 1.5Gb Ram importing to FCP via the PC Card slot and saving via FW400 to a Lacie 250GB 7200rpm Hard Disk Drive I have been able to get time down too 7 or 8mins. Importing to the internal hard drive (5400rpm? ) on the Powerbook was approximately 30secs slower . Staying away from USB2 seems to really make a difference.
Curiously it took 6-7 mins do a straight copy of the P2 files to the external hard drive. Then about another 6-7mins to have FCP import the files. Not much speed benefit to going down that road.Out of curiosity does anyone know if there are any theoretical limits to the speed the data transfers can happen? Im wondering when we see the arrival of storage devices that hold 100Gb of data, how long it will take to offload that much footage. Having hour long uninterrupted downloads in the field presents another set of issues to ‘refine’.
As of next week I will start renting the camera out to my clients. It will be interesting times ahead.
Best
John -
1 Reply
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[john chater] “Out of curiosity does anyone know if there are any theoretical limits to the speed the data transfers can happen?”
The first bottleneck is the hard disk speed; most hard disks max out at about 30 megabytes per second or so. Assuming you use a SATA RAID (or equiv.) that can sustain more than 80 megabytes per second, the next bottleneck would be the firewire or USB2 connection. FW400 maxxes out at a theoretical 50 megabytes per second. The card itself is typically the fastest element in the chain; the card supports 80 megabytes per second.
So if you had a 100-megabyte-per-second RAID, directly connected to the slot (i.e., not using FW or USB), then you could hit the maximum transfer rate. At that rate a 4GB card would offload in maybe 50 seconds.
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