[iyonix-support] Re: external USB hard disk

On 2 May 2007 george <george.greenfield@xxxxxxxxxxxxx> wrote:
> According to !Speed, my Iyo's USB-2 interface will write data to a CF
> digital camera card at rates ranging from 869KB (512KB block) through
> 467KB ((64KB block) down to 12KB for a IKB block size. So taking a
> typical block size of 64KB and assuming a similar transfer rate, it
> would theoretically take approx. 10 hours to write the contents of a
> 20GB drive.

One assumes your files are slightly larger than 64KB on average. 
!DiscKnight can provide some statistics in this area.

> Now if some more knowledgeable soul should tell me I've put the
> decimal point in the wrong place or committed another error of logic,
> I shan't be surprised...

I'm limited by only having relatively slow flash media to test, but 
I've achieved sustained writing 1800KB speeds over USB2. However 
writing lots of small files will result in a fairly slow transfer over 
any external interface (USB or network) due to the overhead of writing 
the map and directories.

As ever the fastest and easiest (therefor the most likely to be 
practiced) backup system is a harddrive in a removable caddy. Use 
!DirSync to copy only the files which have changed since the previous 
backup (and to remove files which have moved) and the backup can be 
done in under an hour while the machine is in normal use.

Cheers
---Dave

-- 
______________________________________________________________________

David J. Ruck   Phone: +44- (0)7974 108301   Email: druck@xxxxxxxxxxxx
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