Re: [Pcbsd-pbi-dev] The pbi format

[Federico L. <flo...@gm...>]

I'm not a programmer or anything, but i always thought that if lets say
FooApp loaded libfoo.so.1 into memory, as it needed it, and BarAPP
needed the same lib, it would be smart enough too see that its already
loaded, and simply use it.
Then again i'm probably wrong :) Although that would be the idea situation.

Cheers

On 2/10/06, Richy T <bio...@gm...> wrote:
>
> Hello pbi developers!
> I have been doing some reading on our pcbsd forums.
> There is some really good information there about our format.
> I really think all PBI developers should read this.
> The information posted on the forum might really help make
> .PBI truly a great binary format for pcbsd and maybe freebsd!
> Here is the post. -->
>
> From: Almindor
> > ---------------
> > I'm a programmer so I'll post my view on PBIs and other packaging here.
> >
> > PBI is a .app style packaging system with "all in one" even basic
> > dependencies. The good of this is that it's simple, easy and has
> > (theoreticly, in practice this isn't true) no conflicts.
> >
> > Packaging ala Ports/Debs/RPMs is a complicated (altho not always for th=
e
> > end user especialy if they have good net connection, debs are real good
> > here) process which required dependency checks etc.
> >
> > Now for the pros and cons from my perspective:
> >
> > PBIs are great for programmers/developers since they make it easy for
> > them to distribute their apps without much fuzz.
> > PBIs however have 2 major problems as-is, one is directly tied to the
> > FreeBSD system underneath:
> >
> > 1. It conflicts with ports/packages
> > 2. It copies all libs for all apps and makes ALOT of duality with .so
> > files.
> >
> > Now #2 seems like no problem to most of you guys but let me elaborate.
> >
> > Dynamic libraries, or shared objects as Unix world calls them are piece=
s
> > of code (and sometimes data too) which are saved in a special way so th=
at
> > programs(apps) can "link" themselves to the code and use it.
> >
> > The whole concept of shared objects is, sharing memory Smile (how
> > unexpected)
> >
> > What's wrong with per-program copy of .so files then?
> >
> > Memory usage. Start up KDE and a few apps, then look at your memory
> > usage via some monitor program. Notice that most apps (visual kde etc) =
take
> > 10+megs of RAM. This ISNT REAL MEMORY.
> >
> > Because all of these programs use more or less the same .so files, all
> > this memory is shared.
> >
> > Now imagine a system where virtualy everything comes from PBI. Every
> > program would really hog ram with it's own copies of .so files (and hen=
ce
> > their existance is a hindrance, since smart-static linking would produc=
e
> > much smaller footprint, less conflicts etc.)
> >
> > Conclusion? It's a good idea on a bad system. I've nothing agains Unix
> > in general but Unix world (and windows too to an extent) decided to go =
the
> > "shared object" path. Every unix binary today links dynamicly etc.
> >
> > Is there a different approach?
> >
> > Well there is, but if it's better is a nice question. Now before I star=
t
> > this please note that I AM biased Smile
> >
> > Free Pascal compiler can produce "smart linked" binaries. These binarie=
s
> > are static but contrary to popular belief take very little space on dis=
k and
> > in memory. (Hello world app in C static linked is ~800kb!! in FPC
> > smartlinked it's ~20kb on disk, I'll explain why)
> >
> > Smart linking is a technique which "links in" only used code from a
> > library.
> >
> > So let's say libC is smartlinkable (it's not btw).
> >
> > If you only used printf() your binary would only grow "so" much.
> >
> > If you use dynamic .so, your binary will remain small on disk, but will
> > load the whole libC into memory because of printf(). Now imagine all
> > programs loading whole libC into memory per-copy. This is what is done =
with
> > PBIs and that's the bad idea. PBIs would work wonders on a "smartlink" =
based
> > system where only real basic system libs would be dynamic, and all othe=
r dev
> > libs would be smartlinkable. This way programs would have minimal footp=
rints
> > and no conflicts would happen (they would also have a tendency to work
> > longer since ABI is of no concern).
> >
> > Hope this all makes a bit of sense Smile
> >
> > Ales
>
>
>    POST REPLY:
>
> From: pcbsdusr
> > ----------------
> > I have been thinking of this as well and i am in the process of writing
> > a hibrid concept which uses programs in their own folders but shares
> > dependencies while maintaining the ability to use multiple versions of =
any
> > given library side by side.
> >
> > no multiplication of libraries =3D No wasted disk space and no memory
> > waste while multitasking with apps using common dependencies.
> >
> > of course, i am writing this for apps only... There will be always
> > duplication until we maintain freebsd intact under pcbsd...
>
>
> I really hope you guys can update the format to work this way.
> It would make the .pbi format truly one of, if not the best format for
> pcbsd/freebsd/UNIX systems.
> Hope this gives you guys some insight and inspiration on how to update th=
e
> .pbi format.
>
> - Richy
>
>
>
>
>