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From: John Levine on 6 Mar 2010 17:22
>>occupy fixed place in memory, whereas in case of ELF,
>>the shared libraries can be loaded anywhere in memory.
>
>This is not true. Typical implementations of shared libraries with
>a.out did not use fixed addresses.

They did it both ways. BSDI had fixed address static libraries, SunOS
as I recall had relocatable.

Either way, doing shared libraries with a.out was a kludge, and ELF
handles them much more tidily.

R's,
John
From: karthikbalaguru on 6 Mar 2010 21:08
On Mar 7, 3:22 am, John Levine <jo...(a)iecc.com> wrote:
> >>occupy fixed place in memory, whereas in case of ELF,
> >>the shared libraries can be loaded anywhere in memory.
>
> >This is not true.  Typical implementations of shared libraries with
> >a.out did not use fixed addresses.
>
> They did it both ways.  BSDI had fixed address static libraries, SunOS
> as I recall had relocatable.
>

Interesting to know that in the case of SunOS it was relocatable !!

Is there any chart/table/diagramatic representation that brings out
the
a.out and the related changes w.r.t various versions of Operating
Systems along with the timeline/history ?

> Either way, doing shared libraries with a.out was a kludge, and ELF
> handles them much more tidily.
>

Thx in advans,
Karthik Balaguru
From: Richard Tobin on 8 Mar 2010 09:59
In article <2f75f973-7ccd-45dd-ba48-055f8c783581(a)v20g2000prb.googlegroups.com>,
karthikbalaguru <karthikbalaguru79(a)gmail.com> wrote:

>> They did it both ways. �BSDI had fixed address static libraries, SunOS
>> as I recall had relocatable.

>Interesting to know that in the case of SunOS it was relocatable !!

As it was in FreeBSD.

-- Richard
--
Please remember to mention me / in tapes you leave behind.
From: Casper H.S. Dik on 8 Mar 2010 10:13
John Levine <johnl(a)iecc.com> writes:

>>>occupy fixed place in memory, whereas in case of ELF,
>>>the shared libraries can be loaded anywhere in memory.
>>
>>This is not true. Typical implementations of shared libraries with
>>a.out did not use fixed addresses.

>They did it both ways. BSDI had fixed address static libraries, SunOS
>as I recall had relocatable.

Not "relocatable" but rather "position independent".
"Relocatable" requires fixups in the code after loading;
"position independent" did not. The SunOS loader was able to
relocatable libraries also, but they can't be shared.

a.out only has a few sections; ELF has an unlimited number.

Casper
--
Expressed in this posting are my opinions. They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.
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