Capitolo 2. Cosa c'è di nuovo in Debian 9


2.1. Architetture supportate
2.2. Cosa c'è di nuovo nella distribuzione?
2.2.1. CD, DVD e BD
2.2.2. Sicurezza
2.2.3. MariaDB replaces MySQL
2.2.4. Improvements to apt and archive layouts
2.2.5. New mirror
2.2.6. Move to "Modern" GnuPG
2.2.7. A new archive for debug symbols

Il Wiki contiene ulteriori informazioni su questo argomento.

2.1. Architetture supportate


FIXME: add item here

Le seguenti architetture sono ufficialmente supportate da Debian 9:

  • PC a 32 bit (i386) e PC a 64 bit (amd64)

  • ARM a 64 bit (arm64)

  • ARM EABI (armel)

  • ARMv7 (EABI hard-float ABI, armhf)

  • MIPS (mips (big-endian) e mipsel (little-endian))

  • MIPS little-endian a 64 bit (mips64el)

  • PowerPC little-endian a 64 bit (ppc64el)

  • IBM System z (s390x)

Maggiori informazioni sullo stato dei port e informazioni specifiche sul port per la propria architettura sono disponibili nelle pagine web relative ai port di Debian.

2.2. Cosa c'è di nuovo nella distribuzione?

 TODO: Make sure you update the numbers in the .ent file 
     using the script found under ../

Ancora una volta la nuova versione di Debian contiene molto più software rispetto alla precedente, jessie; la distribuzione include più di 15346 nuovi pacchetti, per un totale di oltre 51687 pacchetti. La maggior parte del software nella distribuzione è stata aggiornata: più di 29859 pacchetti software (corrispondenti al 57% di tutti i pacchetti in jessie). Inoltre, un notevole numero di pacchetti (oltre 6739, il 13% dei pacchetti in jessie) è stato rimosso dalla distribuzione per diversi motivi. Non ci saranno aggiornamenti per questi pacchetti ed essi saranno marcati come «obsoleti» nelle interfacce dei programmi di gestione dei pacchetti; vedere Sezione 4.8, «Pacchetti obsoleti».

Debian viene ancora una volta fornita con molti ambienti e applicazioni desktop. Fra l'altro include ora gli ambienti desktop GNOME 3.22, KDE 5.8, Xfce 4.12, MATE 1.16 e LXDE.

Anche le applicazioni per la produttività sono state aggiornate, incluse le suite per l'ufficio:

  • LibreOffice viene aggiornato alla versione 5.2;

  • Calligra viene aggiornato a 2.9;

Tra gli aggiornamenti di altre applicazioni per il desktop è incluso l'aggiornamento di Evolution a 3.22.

Fra i molti altri, questa versione include anche i seguenti aggiornamenti software:

PacchettoVersione in 8 (jessie)Versione in 9 (stretch)
BIND Server DNS9.99.10
Exim, server predefinito per la posta elettronica4.844.88
Firefox45.5 (alias Iceweasel)50.0
GNU Compiler Collection come compilatore predefinito4.96.2
la libreria C GNU2.192.24
Immagine del kernel Linuxserie 3.16serie 4.8
MTA Postfix2.113.1
Python 33.43.5
 TODO: (JFS) List other server software? RADIUS? Streaming ?

Debian supporta il Linux Standard Base (LSB), versione 4.1, con una deroga esplicita specifica di Debian alla specifica 4.1 di LSB: non è incluso Qt3.

2.2.1. CD, DVD e BD

The official Debian distribution now ships on 12 to 14 binary DVDs (depending on the architecture) and 12 source DVDs. Additionally, there is a multi-arch DVD, with a subset of the release for the amd64 and i386 architectures, along with the source code. Debian is also released as Blu-ray (BD) and dual layer Blu-ray (DLBD) images for the amd64 and i386 architectures, and also for source code. Debian used to be released as a very large set of CDs for each architecture, but with the stretch release these have been dropped.

2.2.2. Sicurezza

For the stretch release, the Debian version of the GNU GCC 6 compiler now defaults to compiling "position independent executables" (PIE). Accordingly the vast majority of all executables will now have address space layout randomization" (ASLR), which is a mitigation for a number of exploits that are now probabilistic rather than deterministic.

2.2.3. MariaDB replaces MySQL

MariaDB is now the default MySQL variant in Debian, at version 10.1. The Stretch release introduces a new mechanism for switching the default variant, using metapackages created from the mysql-defaults source package. For example, installing the metapackage default-mysql-server will install mariadb-server-10.1. Users who had mysql-server-5.5 or mysql-server-5.6 will have it removed and replaced by the MariaDB equivalent. Similarly, installing default-mysql-client will install mariadb-client-10.1.


Note that the database binary data file formats are not backwards compatible, so once you have upgraded to MariaDB 10.1 you will not be able to switch back to any previous version of MariaDB or MySQL unless you have a proper database dump. Therefore, before upgrading, please make backups of all important databases with an appropriate tool such as mysqldump.

The virtual-mysql-* and default-mysql-* packages will continue to exist. MySQL continues to be maintained in Debian, in the unstable release. See the Debian MySQL Team wiki page for current information about the mysql-related software available in Debian.

2.2.4. Improvements to apt and archive layouts

The apt package manager has seen a number of improvements since jessie. Most of these apply to aptitude as well. The following is a selected highlight of some of these.

On the security side, apt now rejects weaker checksums by default (e.g. SHA1) and attempts to download as an unprivileged user. Please refer to Sezione, «Nuovi requisiti per repository APT» and Sezione, «APT ora recupera i file con un utente non privilegiato («_apt»)» for more information.

The apt-based package managers have also gotten a number of improvements that will remove the annoying "hash sum mismatch" warning that occurs when running apt during a mirror synchronisation. This happens via the new by-hash layout, which enables apt to download metadata files by their content hash.

If you use third-party repositories, you may still experience these intermittent issues, if the vendor does not provide the by-hash layout. Please recommend them to adopt this layout change. A very short technical description is available in the Repository format description

While possibly mostly interesting for mirror administrators, apt in stretch can use DNS (SRV) records to locate a HTTP backend. This is useful for providing a simple DNS name and then managing backends via DNS rather than using a "redirector" service. This feature is also used the new Debian mirror described in Sezione 2.2.5, «New mirror».

2.2.5. New mirror

Debian now provides a new additional service called It provides the content of the main archive, the security archive, ports and even our new debug archive (see Sezione 2.2.7, «A new archive for debug symbols») under a single easy to remember hostname.

This service relies on the new DNS support in apt, but will fallback to a regular redirect for HTTPS access or older versions of apt. More details are provided on

Thanks to Fastly and Amazon CloudFront for sponsoring the CDN backends behind this service.

2.2.6. Move to "Modern" GnuPG

The stretch release is the first version of Debian to feature the "Modern" branch of GnuPG in the gnupg package. This brings with it elliptic curve cryptography, better defaults, a more modular architecture, and improved smartcard support. The modern branch also explicitly does not support some older, known-broken formats (like PGPv3). See /usr/share/doc/gnupg/README.Debian for more information.

We will continue to supply the "classic" branch of GnuPG as gnupg1 for people who need it, but it is now deprecated.

2.2.7. A new archive for debug symbols


This section is mostly interesting for developers or if you wish to attach a full stack trace to a crash report.

Previously, the main debian archive would include packages containg debug symbols for selected libraries or programs. With stretch, most of these have been moved to a separate archive called the "debian-debug" archive. This archive contains the debug symbol packages for the vast majority of all packages provided by Debian.

If you want to fetch such debug packages, please include the following in your apt sources:

deb stretch-debug main

Alternatively, you can also fetch them from

Once enabled, you can now fetch debug symbols for the package in question by installing pkg-dbgsym. Please note that individual packages may still provide a pkg-dbg package in the main archive instead of the new dbgsym.