Ways of starting some SW from floppy

Started by Petari, 15-12-2022, 09:59:17

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It seems that this, in fact pretty simple thing is not really well known. So, little about:
Basic way is to double click on icon of SW-s starter program - what can be with extension PRG, TOS and in rarer cases APP, TTP ..  About this extensions in next post here ...
Little help can be that there is saved Desktop layout in file DESKTOP.INF, so user needs not to do it self, and seek starter program. And that works with all TOS versions.

What also works with all TOS versions is AUTO folder run. What means that TOS will run all files located in folder /AUTO (works with hard disks too, from C: ) which have extension PRG , in order as they are in that folder (so not alphabetically) . That's used a lot, mostly with games.
What is good to know:  AUTO folder run is performed before GEM (AES) init, so only SW not using GEM will work (GEM means: menus, windows ...) .  And again - games are such in big %-age.  And something interesting: because no GEM(AES), there is little more free RAM for running SW. But most of SW does not using it. Exception is Dungeon Master - they achieved with it that it works with 512 KB RAM on Atari (Amiga v. needs 1 MB min).

Third way of starting is so called autoboot. And it happens even before AUTO folder run, actually even before starting TOS FAT filesystem handler. Code in bootsector (with special checksum as sign that is for execution) needs to perform disk loads on low level, so not by filenames, but location on disk.
And it is used by plenty of games - recognizable by not having regular files on them.  Advantage is more free RAM for running SW (no need for diverse buffers of FAT filesystem and some other things used by TOS).

Above 3 work with all TOS versions.

4th way is so called Desktop auto run. It is present at TOS 1.04 .  Possible to set some program to start automatically after GEM (AES) init - solution for automatic run of SW using GEM . User needs to mark that program as AUTO in Install Application, and of course to save Desktop.

To add that all above works from hard disks too. Of course autoboot is used for hard disk driver activation then.  AUTO folder run mostly to activate some resident SW, or some special settings.

Looking diverse SW, in my case mostly games, I can say that from some reason there is plenty of SW where those possibilities were not used.  Not even Desktop saved.
And plenty of cases that there is start from Desktop, while AUTO folder run could be used.  More about in next post here ...


File extensions for executable files for TOS:
It can be PRG, TOS, TTP, APP .
PRG is for SW using GEM/AES, so dialogs, menus, windows ..
TOS is for SW not using above , just GEMDOS functions .
TTP - TOS takes parameters - it is basically way to pass command line to starting program, so it starts with text input.
APP is practically same as PRG .
There is extension ACC too, and it is for SW what automatically loads at start of Desktop. Can activate it's dialog in Desk menu. Although dialog is not mandatory, some ACC may just do something in background.

And little confusion with AUTO folder start: it executes SW with extension PRG, but that's for GEM/AES SW. While it is not initialized when AUTO folder run is activated. Extension TOS would be better in my opinion.

There is plenty of SW without automatic start, even when it would be good to use - like having more free RAM for SW.  Example: SW not using GEM/AES with extension PRG, startable from Desktop. AUTO folder would be better.
Then, there is plenty of SW not using GEM/AES, but having some Trap #2 calls for (parameter 200 before call) - for simple functions like reading mouse, init something. That can be solved with functions available in GEMDOS .
The result is not possible to use AUTO folder run. I modded some to override it, but that needs plenty of time.
At least now we have more RAM, so that's not the problem.

Finally, little about RAM handling of TOS. After reset, clean RAM (no resident SW, ACC) start address of some program in TOS 1.04 is $12596 if extension is PRG , and $F196 if extension is TOS . That's about 13 KB, and that may be good in some cases. However, if starting first some *.PRG, exit it and then start some *.TOS, it will start on that higher address. Well, actually little higher. Every new start is 14 bytes higher loc. in case of same extension. Not some big flaws, but there is reset button for put it in initial stage, with most free RAM.