Re: [Freedos-devel] Re: FreeCOM environment

[Steffen K. <Ste...@fh...>]

On Wed, 30 Jun 2004, Arkady V.Belousov wrote:

Hello Arkady,

> 30-=E9=C0=CE-2004 00:54 _fr...@fr... (FreeCOM) wrote to
> fre...@li...:

OK, I actually seem to have misinterpreted your description that INSTALL=3D=
=20
and SHELL=3D programs will get passed an EnvSeg =3D=3D 0, as this is wrong,=
=20
please ignore anything I said about this topic.

> F> 2. Do you suggest that when FreeCOM.ParentPSP =3D=3D 0, FreeCOM is to =
assume
> F> that it runs from either INSTALL=3D or SHELL=3D and shallt assume /P?
>
>     Do you mean: "if FreeCOM finds that its _parent_ PSP contains
> ps_parent=3D=3D0 (ie, it have no grandfather), then it should make yourse=
lf

No, I did interpreted your explanation wrong.

> permanent (set own ps_parent yo itself)?"? Yes, this behavior may be usef=
ul:
> some users may forget to add /P into SHELL=3D line and will be confused a=
fter
> casual extra line (because, unlike MS-DOS, which automatically tries to
> restart command.com, FreeDOS directly asks path to command interpreter).

Good, I will file this as enhancement request.

>     Don't know about "unused" (may be, MS-command.com uses it for own
> needs), but yes: original block remains in memory:

Wild guess:
maybe, this is the persistent environment you were searching for? (For to=
=20
pass the environment to the next SHELL, once the SHELL=3D program=20
terminates?)

> F> Anyway, I made the /LOW option of FreeCOM work. So you can relocate th=
e
> F> environment block whereever you like from within AUTOEXEC.BAT. As I
>
>     How? As I understand, this may and should affect already runned
> (primary) FreeCOM only if this options given before its run (for example,
> SHELL=3Dcommand.com /low /p)? And, who says that placing environment into
> upper memory is bad? I say, that using LAST_FIT is bad stategy (for UMBs
> this makes inoptimal memory usage, in low memory this makes fragmented

So, why would be "FIRST_FIT" or even "BEST_FIT" optimal? It cannot,=20
neither. Optimal would be when the user could decide where to place which=
=20
part. But this is no option at the current time.

> F> said: FreeCOM relys on the FreeCOM.EnvSeg pointer for all its operatio=
ns
> F> and it is guaranteed that all cached data is flushed, when FreeCOM get=
s
> F> re-activated after running an external command.
>
>     This is your deal, I don't say anything about FreeCOM own (child) PSP=
=2E

Huh? You said you need to have the environment segment placed somewhere=20
else. I did not mentioned the PSP as well. You can write a program to move=
=20
the parent's environment to any location you like. That is the most=20
optimal placement I can imagine.

> F> It is currently not possible to use FIRST_FIT (and therefore BEST_FIT
> F> neither) and I do not hassle with the XMS code to move the environment
> F> segment around.
>
>     Look at memory map above again. And look at FreeCOM map:
>
> ______________O\_/_________________________________\_/O______________
>  -0FA7   2.01k               STACKS=3D
> 0FA7       64                --free--
> 0FAB     2.87k   COMMAND
> 1063      574k               --free--
> 9FEF      272    COMMAND     environment
> -A000-
> _____________________________________________________________________
>              O/~\                                 /~\O

But what do I see here in conjunction that "It is currently not possible=20
to use FIRST_FIT (and therefore BEST_FIT neither)" for FreeCOM?

Bye,

--=20

Steffen Kaiser