> -----Original Message----- > From: Linux on 390 Port [mailto:[EMAIL PROTECTED]]On Behalf Of > Holger Baxmann > Sent: Thursday, February 28, 2002 1:41 PM > To: [EMAIL PROTECTED] > Subject: Re: create an ISO from a CD > > > 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 >
cp isn't a bash (or other shells as far as I know) buildin command, so it should not depend on the shell. And I have not normaly an alias for cp neither for rm. dd could be an alias too. To be sure it is not, you may quote your command. There are dozens of ways to copy files. Choose the way you like. And check that you know what you are doing. Georg
