Am Don, 2002-02-28 um 13.16 schrieb Malcolm Beattie: > Holger Baxmann writes: > > Am Mit, 2002-02-27 um 23.32 schrieb Alan Cox: > > > > > dd if=<your cd device name goes here/> of=MyLovelyMVSImage.iso > > > > > > > > I don't know why "everyone" recommends dd for this purpose. I've been > > > > using the easier cp command and it works perfectly well. dd has extra > > > > options, but they're not needed in this case. > > > > > > Basically Unix history. There was a time when you really did normally > > > have to use dd for this. Thirty odd years ago anyway 8) > > unfortunately not - it is the *nix present. > > [...] > > mention the various cp commandline parameters. the cp option is > > definetly the uglyest - it give you days of work to find out that the > > file and directory user and owner are _not_ copied, that you are missing > > some of the permissions ..... etc. etc. the appropriate commandline > > option is at mindest: > > > > cp -a indevice outfile > > > > this is not implemented in all *nixes, this is implemented in a diffrent > > manner in any version of your current version and distribution of *nix > > if it is. > > so if you are using a more complex command then needed - you will > > running into more complex problems - then needed. > > > > and this is true since thirty years ago. > > You appear to have missed the point. There is no issue with permissions, > owners or recursion at all. It is the filesystem *image* that is being > copied. It is the equivalent of doing a DDR to copy an FBA volume > except that the output is a file. That file can then be used directly to > burn a new CD or mount live (via loopback) or whatever else you like. > It's just a stream of bytes (modulo alignment at the end to the next > sector/block but that's not at issue here). > sorry for expressing myself misunderstandingly :) this is exactly what i mean by using dd as the appropriate command and not cp or mkisofs. cp and mkisofs are implementation and this way *nix _installation_ dependend in their behavior, some is able to _hope_ they are doing the same that a simple dd does - but it is unpredictable: you are for example able to overload the behavior of the plain cp via an entry in your shell-alias file in bash, rm normally does not ask for deletion confirmation, it does it because you have a "rm -i" entry in your bash config. the command behaves totaly different if you are using another shell ash, tch, ksh.
so, beware of the automagics, stay simple, be stupid, use dd --- for the next thirty yaers of *nix bax > Regards, > --Malcolm > > -- > Malcolm Beattie <[EMAIL PROTECTED]> > Linux Technical Consultant > IBM EMEA Enterprise Server Group... > ...from home, speaking only for myself
