Hi,

I just came across a StackOverflow question[1] where someone wants an installation medium that works offline but does not ask for the extra
disks unless they are necessary.

Since we need the indexes and disc IDs, this is difficult to do with the current setup, but in principle I think it should be possible to add
this information to the first medium in a set, and change the question
to "how many installation disks do you have?" (which would be easier to preseed)

Given that the later media are seldom used, most users can probably
avoid switching media altogether -- but in a completely offline install,
this is the only way to get a complete index.

Simon

[1] https://unix.stackexchange.com/q/796672

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Fri, Jun 06, 2025 at 06:31:27AM +0900, Simon Richter wrote:

Hi,

I just came across a StackOverflow question[1] where someone wants an installation medium that works offline but does not ask for the extra disks unless they are necessary.

apt-cdrom add DVD1 - repeat for DVD2 and DVD3.

apt-install package foobar will ask for the DVD it comes from

That's the *right* answer as it stands at the moment, I think.
I've used this several times so know that it works.

To be honest, it's a *lot* easier to just use jigdo to make a 16G
stick / BD image and use that as your base.

Since we need the indexes and disc IDs, this is difficult to do with the current setup, but in principle I think it should be possible to add this information to the first medium in a set, and change the question to "how many installation disks do you have?" (which would be easier to preseed)

Given that the later media are seldom used, most users can probably avoid switching media altogether -- but in a completely offline install, this is the only way to get a complete index.

If you're doing this offline, then you probably ought to also be generating
the other DVD images anyway to take with you to your desert island in
order to prove that Debian's desert island test remains valid.

All the very best,

Andy
([email protected])

Simon

[1] https://unix.stackexchange.com/q/796672

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --------------9SmqjxuaHQRFNti2iFT2A270
Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: base64

SGksDQoNCk9uIDA2LjA2LjI1IDA2OjM4LCBBbmRyZXcgTS5BLiBDYXRlciB3cm90ZToNCg0K PiBJZiB5b3UncmUgZG9pbmcgdGhpcyBvZmZsaW5lLCB0aGVuIHlvdSBwcm9iYWJseSBvdWdo dCB0byBhbHNvIGJlIGdlbmVyYXRpbmcNCj4gdGhlIG90aGVyIERWRCBpbWFnZXMgYW55d2F5 IHRvIHRha2Ugd2l0aCB5b3UgdG8geW91ciBkZXNlcnQgaXNsYW5kIGluDQo+IG9yZGVyIHRv IHByb3ZlIHRoYXQgRGViaWFuJ3MgZGVzZXJ0IGlzbGFuZCB0ZXN0IHJlbWFpbnMgdmFsaWQu DQoNClllcywgdGhlIHByb2JsZW0gaXNuJ3Qgc28gbXVjaCAiaGF2aW5nIHRoZSBtZWRpYSIg YXMgImhhdmluZyB0byBzd2FwIHRoZSANCm1lZGlhLiIgVGhlIHNvbHV0aW9uIHByb3Bvc2Vk IGJ5IHRoZSBxdWVzdGlvbiBhc2tlciBpcyB3cm9uZywgYnV0IHRoZSANCnByb3BlciBzb2x1 dGlvbiB3b3VsZCByZXF1aXJlIHN1cHBvcnQgZHVyaW5nIGltYWdlIGdlbmVyYXRpb24uDQoN ClJpZ2h0IG5vdywgaWYgeW91IGhhdmUgYWxsIDUwIG9yIHNvIERWRHMsIGEgZnVsbHkgb2Zm bGluZSBpbnN0YWxsYXRpb24gDQpyZXF1aXJlcyB5b3UgdG8gcHJlc2VudCBhbGwgb2YgdGhl bSB0byB0aGUgaW5zdGFsbGVyLCBpbiB0dXJuLCBiZWZvcmUgDQppbnN0YWxsYXRpb24gc3Rh cnRzLCBzbyA1MCBkaXNjIGNoYW5nZXMuIFRoZW4sIGlmIHlvdSBkbyBhIGRlZmF1bHQgDQpp bnN0YWxsYXRpb24sIHlvdSBvbmx5IG5lZWQgZGlzYyAxLCBhbmQgZmVlbCBhIGJpdCBzaWxs eSBmb3IgZG9pbmcgdGhlIA0KZW50aXJlIGRhbmNlIGJlZm9yZS4NCg0KUHJvYmxlbSBpcywg dGhlcmUgaXMgYWxzbyBubyB3YXkgZm9yIHRoZSB1c2VyIHRvIGtub3cgd2hpY2ggZGlzY3Mg YXJlIA0KbmVlZGVkIGJlZm9yZSBwYWNrYWdlIHNlbGVjdGlvbiwgYW5kIHRoZSBwZXJzb24g YXNraW5nIHRoZSBxdWVzdGlvbiBoYWQgDQppbnN0YWxsYXRpb25zIGZhaWwgYmVjYXVzZSB0 aGV5IGFzc3VtZWQgdGhleSBjb3VsZCBnZXQgYXdheSB3aXRoIG9ubHkgDQphZGRpbmcgdGhl IGZpcnN0IHRocmVlIGRpc2NzLCBidXQgb24gdGhhdCBwYXJ0aWN1bGFyIG1hY2hpbmUsIGEg cGFja2FnZSANCmZyb20gYSBsYXRlciBkaXNjIHdhcyByZXF1aXJlZC4gV2UgZG9uJ3QgZ2l2 ZSBvdXQgZ3VpZGFuY2UgbGlrZSAiaWYgeW91IA0KbmVlZCB4ZmNlLCB5b3UgYWxzbyBuZWVk IGRpc2MgMyBhbmQgNCIsIGZvciBnb29kIHJlYXNvbnMsIGJ1dCBpdCBtZWFucyANCnRoYXQg YWlyZ2FwcGVkIGluc3RhbGxhdGlvbnMgYXJlIHZlcnkgY3VtYmVyc29tZS4NCg0KU28gaWYg ZGlzYyAxIGFsc28gaGFkIHRoZSBpbmRleGVzIGF2YWlsYWJsZSBmb3IgdGhlIG90aGVyIGRp c2NzLCB3ZSANCmNvdWxkIHNpbXBseSBhc2sgIndoaWNoIGluc3RhbGxlciBkaXNjcyBkbyB5 b3UgaGF2ZSBhdmFpbGFibGU/IiAoY29tbWEgDQpzZXBhcmF0ZWQgbGlzdCBvZiByYW5nZXMp LCBhZGQgdGhlaXIgaW5kZXhlcyBmcm9tIHRoYXQgcHJvbXB0LCBhbmQgdGhlbiANCmFzayBv bmx5IGZvciB0aGUgcmVxdWlyZWQgb25lcyBkdXJpbmcgaW5zdGFsbGF0aW9uLiBUaGUgdXNl ciB3aWxsIHN0aWxsIA0KbmVlZCB0byBwcmVwYXJlIGFsbCBvZiB0aGVtIGlmIHRoZXkgbmVl ZCB0aGUgZ3VhcmFudGVlIHRoYXQgdGhleSB3aWxsIGJlIA0KYWJsZSB0byBjb21wbGV0ZSBh biBpbnN0YWxsYXRpb24sIGJ1dCBhdCBsZWFzdCB0aGUgbnVtYmVyIG9mIGRpc2Mgc3dhcHMg DQp3aWxsIGJlIGdyZWF0bHkgcmVkdWNlZC4NCg0KICAgIFNpbW9uDQo=

--------------9SmqjxuaHQRFNti2iFT2A270--

-----BEGIN PGP SIGNATURE-----

iQEzBAEBCgAdFiEEtjuqOJSXmNjSiX3Tfr04e7CZCBEFAmhDsRsACgkQfr04e7CZ CBEuQgf8CEVq3/LA+neTxRimiGlQE/I2MTwBJl172iR8baPESGtBzWFetCvGxEvC Kv08u02jqTarwI7/TwfM286rrczVr0ViBFIaqqWOogRJ/78etSJsXtDJyu7Vm556 iNsq7avqWCM+UGshpZ0YAxlpM/NJ0Gc6t3Zq8uT/kubL36tb22e3zc/d8jCXnoCy KFPXUZ87wYkJmQvwhRBd+e0CZFBi7dgU1j1CPBFwqHRC+/8yfgyU4phi31r9Q7gV GzZRlvM5J80whVd3AX/nQCQrctRxbpF/EJrme0jJ68HHuQCjjG3ZNT3tl1pSiBCf JyakrcG1o809tMpLajTFhZVhtWEaWA==
=ahQO
-----END PGP SIGNATURE-----

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sat, Jun 07, 2025 at 12:25:14PM +0900, Simon Richter wrote:

Hi,

On 06.06.25 06:38, Andrew M.A. Cater wrote:

If you're doing this offline, then you probably ought to also be generating the other DVD images anyway to take with you to your desert island in
order to prove that Debian's desert island test remains valid.

Yes, the problem isn't so much "having the media" as "having to swap the media." The solution proposed by the question asker is wrong, but the proper solution would require support during image generation.

Right now, if you have all 50 or so DVDs, a fully offline installation requires you to present all of them to the installer, in turn, before installation starts, so 50 disc changes. Then, if you do a default installation, you only need disc 1, and feel a bit silly for doing the
entire dance before.

At this point, I'd probably use the Blu-Ray disks or even the dlbd
double layer Blu-Ray**

** The usefulness of these in general is fairly small though the numbers
of users still using these is unknown. Almost certainly at this point,
nobody still uses these on real, expensive physical media rather than
copying them to a USB stick. The Debian images and install media team
may eventually further rationalise the numbers of images and jigdo files released at each point release.

Problem is, there is also no way for the user to know which discs are needed before package selection, and the person asking the question had installations fail because they assumed they could get away with only adding the first three discs, but on that particular machine, a package from a
later disc was required. We don't give out guidance like "if you need xfce, you also need disc 3 and 4", for good reasons, but it means that airgapped installations are very cumbersome.

With the varying sizes of packages with every release and the fact that packages are assigned to media by approximate popularity and size to fit
a disk image, this is almost unknowable in advance unless you grep the installed files list. It's a particular struggle to maintain the netinst
at a reasonable size as it is for DVD 1. [DVD 1 is limited to 4GB to allow
the image to be written to a 4GB USB stick, even though it's almost
impossible to find a 4GB USB stick this small these days].

So if disc 1 also had the indexes available for the other discs, we could simply ask "which installer discs do you have available?" (comma separated list of ranges), add their indexes from that prompt, and then ask only for the required ones during installation. The user will still need to prepare all of them if they need the guarantee that they will be able to complete an installation, but at least the number of disc swaps will be greatly reduced.

Agreed but this would also need changes in the installer logic. For the
very limited use case, the pain and problems probably outweigh the disk
space problems on each medium and the complexity of the change required.
If you *really* want the desert island install, it's almost easier to
take a netinst medium and a laptop/small machine with a full Debian mirror

In order to save space on Debian CD mirror machines worldwide, the images beyond DVD3 and equivalents have been reduced to corresponding .jigdo
files and templates so you really need a mirror to create the media for
an offline install anyway.

The size/number of images (and the complexity of maintaining the archive) versus diminishing returns in effort is something we often mention in
passing within the images team while chatting amongst ourselves as we are testing installs and preparing point releases. It is absolutely
true that some images have never been tested over a period of years
as noted in the testing matrix for each point release.

Simon

All the very best, as ever,

Andy Cater
([email protected])

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)