Re: disk vs rdisk, was: How to obtain the FAT serial number form a volume
Re: disk vs rdisk, was: How to obtain the FAT serial number form a volume
- Subject: Re: disk vs rdisk, was: How to obtain the FAT serial number form a volume
- From: Chris Murphy <email@hidden>
- Date: Wed, 29 Feb 2012 19:16:14 -0700
On Feb 29, 2012, at 6:43 PM, Chris Suter wrote:
> Try
> increasing the block size that dd uses and see what happens. It
> defaults to 512 bytes which will be too low.
mingisapsycho:~ chris$ sudo dd if=/dev/rdisk0s4 of=/dev/null bs=1m count=500
524288000 bytes transferred in 6.813068 secs (76953289 bytes/sec)
mingisapsycho:~ chris$ sudo dd if=/dev/disk0s4 of=/dev/null bs=1m count=500
524288000 bytes transferred in 18.793040 secs (27897988 bytes/sec)
It's nearly a 3x performance difference.
Chris Murphy
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