[nmglug] Questions About Dual Booting From A USB Drive

Thu Apr 7 17:03:40 PDT 2005

On Thu, 2005-04-07 at 15:41 -0600, William D. Nystrom wrote:
> So I don't actually know all that much about Debian.  For straight Debian,
> do you have to choose between stable, testing and unstable or can you have
> some or all of the three different flavors?  Your email seems to imply
> that you need something like Ubuntu or Mepis to use all three flavors at 
> once.

You can use packages from all three Debian _releases_, and/or any of the
other Debian-based distros at once in any of them.   All of the Debian-
based distros utilize the same package management software.  Mixing
Ubuntu and Mepis is probably not fully tested and is certainly not
supported, but it probably is possible to get a working configuration
without too much hassle if you understand how it works.  Mixing Ubuntu
and Debian seems to be working fine for me.

Here's a description my configuration, which is also attached.  I
initially installed Ubuntu "Warty Warthog", and then moved over to
"Hoary Hedgehog", which will be released fairly soon.  I did that by
adding new entries to "sources.list" and fixing up the "preferences"
file priority numbers.  Just recently, I also added the Debian
repositories to it.

The "preferences" file's purpose and syntax is described in 'man
apt_preferences'.  Rather than re-explain it here, I'll leave you to
read that.  This one makes my local repository (if it exists; it does
not, presently) have priority 999, and the one at laclinux have priority
995.  These are deliberately < 1000, which is a magic priority --- RTFM.
The default repository, at Ubuntu, for the Hoary Hedgehog release (in
testing now, soon to be released officially), is set at priority 600,
with Warty Warthog (the current release) set at 500.  The Debian
'testing' and 'unstable' archives follow, and finally, anything from the
'experimental' archive is lowest priority.

The "sources.list" file has all of those repositories listed, plus a few
more.  The automatic selection algorithms as explained in 'man
apt_preferences' decide, based on priority and presently installed
version, which one is picked when I run 'apt-get dist-upgrade' or press
the 'U' button in 'aptitude'.  I prefer to use 'aptitude'.  When I let
it pick the default, it picks packages from Ubuntu "Hoary Hedgehog".  If
I want to, I can manually select the version from Debian 'unstable'.  At
times this means a round of manual dependency fixing, facilitated by the
'aptitude' interface.  Doing that by hand on the 'apt-get' command line,
or using the 'synaptic' GUI would probably be much more difficult.

The final attached file belongs in "/etc/apt/apt.conf.d/05-Cache-Limit".
Without it, 'apt-get update' would fail, running out of room in the
block of memory it allocates for it's internal data structures.  It's a
large chunk, and has backing store in an 'mmap' file, so I suppose
that's why they did not simply re-allocate it when it fills up.  Other
programs in the apt suite must also map that file, so must read the
configuration to learn how large it is... ?  I've not really studied
that software's internals much.

What's good about this setup is that Ubuntu provides a very well
integrated and fully functioning Gnome Desktop Environment.  Most of
Debian is built for Ubuntu also, but they lag behind slightly in getting
newer packages from 'unstable'.  There was some new stuff in 'unstable'
I wanted to try, so I added it.  I also added third-party repositories
to get some goodies not available from Debian or Ubuntu.

-------------- next part --------------
Explanation: See   man apt_preferences
Package: *
Pin: origin ""
Pin-Priority: 999

Package: *
Pin: release o=laclinux
Pin-Priority: 995

Package: *
Pin: release a=hoary
Pin-Priority: 600

Package: *
Pin: release a=warty
Pin-Priority: 500

Package: *
Pin: release o=Debian a=testing
Pin-Priority: 450

Package: *
Pin: release o=Debian a=unstable
Pin-Priority: 400

Package: *
Pin: release a=experimental
Pin-Priority: 300
-------------- next part --------------

deb http://archive.ubuntu.com/ubuntu/ warty main restricted 
deb-src http://archive.ubuntu.com/ubuntu/ warty main restricted 

deb http://archive.ubuntu.com/ubuntu/ warty universe 
deb-src http://archive.ubuntu.com/ubuntu/ warty universe 

deb http://security.ubuntu.com/ubuntu/ warty-security main restricted 
deb-src http://security.ubuntu.com/ubuntu/ warty-security main restricted 

deb http://security.ubuntu.com/ubuntu/ warty-updates main restricted 
deb-src http://security.ubuntu.com/ubuntu/ warty-updates main restricted 

deb http://archive.ubuntu.com/ubuntu/ hoary main restricted 
deb-src http://archive.ubuntu.com/ubuntu/ hoary main restricted 

deb http://archive.ubuntu.com/ubuntu/ hoary universe 
deb-src http://archive.ubuntu.com/ubuntu/ hoary universe 

deb http://security.ubuntu.com/ubuntu/ hoary-security main restricted 
deb-src http://security.ubuntu.com/ubuntu/ hoary-security main restricted 

# deb http://www.laclinux.com/~karlheg/debian/ ./ 
# deb-src http://www.laclinux.com/~karlheg/debian/ ./ 

deb http://people.ubuntu.com/~thom/network-manager/ ./ 
deb-src http://people.ubuntu.com/~thom/network-manager/ ./ 

deb http://jopa.studentenweb.org/debian/ ./ 

deb ftp://ftp.nerim.net/debian-marillat/ unstable main
deb-src ftp://ftp.nerim.net/debian-marillat/ unstable main

#deb http://people.debian.org/~mbanck/ubuntu-hoary/ ./ 
#deb-src http://people.debian.org/~mbanck/ubuntu-hoary/ ./ 

# deb http://people.ubuntulinux.org/~mvo/apt-authentication/ ./ 

# Debian "testing" (presently the same as "Sarge")
#
deb     http://ftp.us.debian.org/debian testing main contrib non-free
deb-src http://ftp.us.debian.org/debian testing main contrib non-free

# Debian "unstable" ("Sid" will always be unstable.)
#
deb     http://ftp.us.debian.org/debian unstable main contrib non-free
deb-src http://ftp.us.debian.org/debian unstable main contrib non-free

# Experimental packages -- be careful about enabling these!  They are
# occasionally broken.
#
deb     http://ftp.us.debian.org/debian/ project/experimental/main/binary-$(ARCH)/
deb-src http://ftp.us.debian.org/debian/ project/experimental/main/source/
# 
# deb     http://ftp.us.debian.org/debian/ project/experimental/contrib/binary-$(ARCH)/
# deb-src http://ftp.us.debian.org/debian/ project/experimental/contrib/source/
#
# deb     http://ftp.us.debian.org/debian/ project/experimental/non-free/binary-$(ARCH)/
# deb-src http://ftp.us.debian.org/debian/ project/experimental/non-free/source/

# Software Suspend Hibernate Scripts (unofficial)
#
deb     http://cp.yi.org/apt/hibernate/ ./
deb-src http://cp.yi.org/apt/hibernate/ ./

# SciPy (unofficial)
#
# deb     http://jrfonseca.dyndns.org/debian ./
# deb-src http://jrfonseca.dyndns.org/debian ./
-------------- next part --------------
// This is needed if you get an error saying that the mmap ran out of
// space.  The setting here should give it plenty!  RTFM.
//
APT::Cache-Limit "16777216";