Re: An INCOMPLETE solution - was [Re: Where is data stored when Synaptic scans DVDs?]
On Sat 25 Mar 2017 at 12:59:50 (+0000), Brian wrote:
> On Fri 24 Mar 2017 at 16:31:25 -0500, David Wright wrote:
>
> > On Thu 23 Mar 2017 at 11:29:38 (+0000), Brian wrote:
> > > On Thu 23 Mar 2017 at 10:12:57 +0000, Darac Marjal wrote:
> > >
> > > > On Wed, Mar 22, 2017 at 08:08:28PM -0500, Richard Owlett wrote:
> > > > >On 03/17/2017 08:47 AM, Richard Owlett wrote:
> > > > >>As I have limited bandwidth, I install from DVDs.
> > > > >>Also I frequently experiment with various options by doing a fresh
> > > > >>install to a different partition.
> > > > >>It is annoying to keep re-scanning a set of 13 DVDs.
> > > > >>Where is the information stored?
> > > > >>/etc/apt/sources.list is obvious, but where is the data about contents
> > > > >>of each DVD stored?
> > > > >>TIA
> > > > >
> > > > >It had been suggested that all the needed information might be in
> > > > >/etc/apt/sources.list
> > > > > PLUS
> > > > >the /var/lib/apt directory
> > > > >
> > > > >It ain't :{
> > > >
> > > > Looking at the source, apt-cdrom does a bunch of checks and then calls into
> > > > pkgCdrom::Add()[1]. That does some more checks and then the interesting
> > > > stuff seems to start around line 746.
> > > >
> > > > The Configuration Database (TODO: Find where this is stored... Ah, I *think*
> > > > that's the /var/lib/apt/cdroms.list mentioned earlier) is checked for
> > > > existance of the CD and updated, if necessary. The next interesting part is
> > > > at line 838 where the packages are copied. This seems to happen in
> > > > IndexCopy::CopyPackages()[2] which, at line 97, creates a file in
> > > > /var/cache/apt/archives/partial/ containing the contents of the cdrom.
> > > >
> > > > [1] http://sources.debian.net/src/apt/1.4~rc2/apt-pkg/cdrom.cc/
> > > > [2] http://sources.debian.net/src/apt/1.4~rc2/apt-pkg/indexcopy.cc/
> > > >
> > > >
> > > > So, in summary, I think you need /etc/apt/sources.list, /var/lib/apt *AND*
> > > > /var/cache/apt/archives.
> > >
> > > Suppose /var/cache/apt/archives is empty because 'apt-get clean' has
> > > been run. What then?
> >
> > Good point. I noticed that the two .bin files in /var/cache/apt/ that
> > https://lists.debian.org/debian-user/2017/03/msg00722.html
> > mentioned, come and go with apt-get update and clean respectively.
> > I had overlooked how ephemeral they are. They're built from scratch at
> > the "Reading package lists... Done" line after the Fetched line.
> >
> > If your only sources are the DVDs then I can't see a problem with just
> > adding those files (or whatever the names are of any files that
> > appear—they could differ with apt-cdrom) to your list of files you
> > (OP) share between systems. It's tricky to check what's actually
> > in them as they're binary databases (what I called "hidden"
> > information previously).
>
> It probably does no harm to transfer them to the target system but they
> can be generated there from 'apt-get update'.
In which case I can't think of any files other than those under
/var/lib/apt/, which always seemed correct to me for index files.
So my parting suggestion is running synaptic under strace and
examining the output at the time it becomes disgruntled and wants
those DVDs to be scanned (which is what the OP wants to avoid having
to do). If that fails, the source of apt/apt-cdrom can be downloaded
and read, which should settle the OP's waters.
Cheers,
David.
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