Date: Wed, 27 Mar 2013 14:10:21 -0700 From: "Ronald F. Guilmette" <rfg@tristatelogic.com> To: freebsd-questions@freebsd.org Subject: Copying memstick image to a USB (flash/thumb) drive Message-ID: <6148.1364418621@server1.tristatelogic.com>
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I've never used any FreeBSD memstick image before, but now I have reason to do so. I'm reading the instructions for creating a bootable memstick that are located on this page: http://www.freebsd.org/releases/9.1R/announce.html which include the following example of how to perform the copy: # dd if=FreeBSD-9.1-RELEASE-amd64-memstick.img of=/dev/da0 bs=10240 conv=sync Question: Why exactly is "conv=sync" is there? Also, in practice what does it actually do? (I've used dd plenty in my lifetime, but never found any reason to use conv= at all. I always thought that it was... mostly... just an archaic leftover from the days when some big iron used EBCDIC that needed to get converted to ASCII or vise versa.) The dd man page describes the "sync" type of "conversion" thusly: "Pad every input block to the input buffer size. Spaces are used for pad bytes if a block oriented conversion value is specified, otherwise NUL bytes are used." Ummm... ok. WTF is a "block oriented conversion value"? How would I know if I had specified one? Question: Why exactly is the "bs=10240" is there? Wouldn't the default of 512 do just as well? Regards, rfg
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