On Fri, Jan 08, 1999 at 06:08:25PM -0500, Kerr wrote:
> On Thu, 7 Jan 1999, Mireles-Cordova, Ricardo wrote:
>
> > According to ELKS FAQ Q1.2
> > ... swapping, shared libraries, parallel and serial I/O, and
> > networking.
> > are not available.
> >
> > Is this still the case?
>
> AFAIK, ELKS supports parallel and serial I/O, but not swapping or shared
> libraries. Both swapping and shared libraries often depend on the
> processor. In the 8086 & 8088, there are no facilities to help the OS
> with these features.
Implementing swapping would be hard on XT class computer since it requires
virtual memory services. However shared libraries can be implemented
easily on XT too. Eg : OS/A65 is a multitasking OS for C64 with
network support (web server, telnet daemon etc) and it SUPPORTS shared
libraries and relocatable binaries. Without any MMU :)
Of course the elegant mmap( ... MAP_SHARED ...)-like way cannot be used
but there can be a syscall to load a library into the memory. If the
library is IN the memory already, kernel only give a pointer to it (and
increment library used counter, if it hits zero on decrement memory
can be freed used by library), else kernel loads the library.
Since code segment should be read-only it's not a problem to share on
the same code.
286 would be used to implement real memory protecting in 286 pmode (and
to use 16Mb directly addressable memory space as well).
I couldn't follow the evolution of ELKS so sorry for my probably bad
informations on the system, and for my poor English as well.
By(T)e : Gabor Lenart
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