1 Just random notes at this point:
3 - Razor is a package management system replacing rpm and yum. Razor
4 implements management of packages installed on the system,
5 dependency solving, and upgrading in a small compact code base with
8 - Key points: one file format for package sets, specified and
9 implemented by razor; no point in splitting dep-solver and package
10 manager, there is too much implementation overlap. By hand coding
11 the on-disk format we have a solid foundation on which to
12 implementing fast dependency solving, error recovery etc. No
13 complex dependencies in package management stack. In other words,
14 package management is *simple*, no need to overdesign it.
16 - Use one simple file format as the core of the system. The razor
17 package set data structure represents a set of packages and is used
18 for the current installed set, the sets available from upstream
19 sources, and the set currently being install during a transaction.
20 Tiered systems such as rpm+yum, deb+apt etc end up duplicating and
21 reimplementing common operations on packages. Other systems
22 typically pull in external database libraries to manage the package
23 meta data and in some cases each layer in the stack uses a
24 different database dependency to represent essentially the same
27 - Using external database libraries may seem a good idea up front,
28 but monotone vs git is a good example of how you need to control
29 the data structure and the on-disk format to really get excellent
30 performance. The razor package set data structure is fairly
31 simple; it's an read-only, mmap()'able on-disk data structure. The
32 package set has a sorted index of the packages in the set, a sorted
33 index of all dependencies and a sorted, compact directory of all
34 files in all the packages. Operations such as merging package
35 sets, satisfying requires from one set against another can all be
36 implemented in linear time. Razor implements the package set
37 representation down to the bytes on the disk and can optimize the
38 representation and access methods to make the necessary operations
41 - The set of installed packages on a system is represented by just
42 one package set file. As we install a set of new packages, we
43 prepare the new package set a temporary file and once the install
44 has succeeded, we copy the package set file to the real filename.
45 If there is a system crash, razor will notice the temporary file on
46 boot and resume the update.
48 - We want to keep the numer of dependencies down in a system critical
49 component such as the package manager. Between rpm and yum we're
50 pulling in berkeley db, sqlite, expat, python.
52 - During update of several packages rpm+yum leaves the system in an
53 inconsistent state for long periods of time. Power failure in this
54 window causes critical system corruption. We want to minimize the