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Re: Some help with dd backing up into an iso

On Tue, Mar 07, 2017 at 10:26:25AM +0200, Teemu Likonen wrote:
> What's the point of using dd?
>     gzip </dev/sda >myimage.img
> I don't know about you but many people seem to think that dd is some
> kind of special tool for reading and writing block device files. But
> after all the devices are just files that can be read with normal
> commands like cat or cp. These are even faster normally because they use
> larger buffers. Write operations on device files should be finished with
> sync command to flush the buffers.

You're right, but I would advocate people use gddrescue instead, rather
than cp etc., since (unlike cp, cat, dd, etc.) gddrescue is very careful
about which blocks it has read, can do retries, keeps a log file, can be
interrupted and resumed safely, and can recover data from failing devices.

Jonathan Dowland
Please do not CC me, I am subscribed to the list.

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