IMGRUN - Image file runner - IMGRUL1-3

Purpose is to make easier running of software (mostly games) from
 diverse floppy image files. Most common formats for Atari ST are 
ST and MSA. Such images are intended for usage with emulators.

Owners of Atari machines with hard disks want to run games from 
hard disk, but it is not possible with most of games in current form. 
Wether game is in some floppy image (menu disk), wether is in 
Atari files, but wont start from hard disk.

This small program will allow above for many (we will see how many
 %-ually by time) Atari ST games - to run them from floppy image
 files on real Ataris, without need to write images on floppies.

Version IMGRUL1: - new version with less resetting:
For faster start of games I made new version, where program not resets
 machine when starts running of image. Plus, no need to make hard reset 
before mounting new image - program will place new image where needed.

Price for it is little preparation: must make snapshot of machine Low RAM
before usage. 
1. step - get one work floppy with some free space and run LOMSNA1.PRG.
It will write special bootsector on floppy A.

2 step - run IMGRUL1.PRG - it will complain about snapshot load error. Click 
MOUNT ST and load 1MRD.ST for DD floppy img. running or 18MR.ST for HD
 floppy img. running. Second is only for machines with 2.5 MB or more RAM.
 After it ensure that previously prepared floppy is in drive A and click GO!. 
Machine will reset and file LOMSNA.BIN of 32000 bytes will appear on floppy A.
You need to prevent harddisk driver load by it (ALT key), and probably reset 
once again.

3 step - copy LOMSNA.BIN to DIR where will run IMGRUL, and may start playing.

Note: snapshot is usable only on machine on which is made. 

ST and MSA images can be mounted. After selecting ST image with fileselector 
program will load it in RAM and set CHS values by bootsector of image.
If you get there some strange values (20 sides, 0 sides and similar) 
you need to enter correct CHS values before clicking GO! button.
 With MSA images editing is not necessary in any case (they hold
 CHS for all weird formats). While loading image file you will see 
couple of small flashes - (program moves video RAM down). 
For starting click 'GO! '. You have about 1 sec to press down 
ALT key -  to prevent load of hard disk driver load. It is 
important because of data safety on hard disks and memory usage. 
If it will load you must run again IMGRUL - AUTO from imaged A
 will not execute with hard disk driver loaded.
NEW: version IMGRUL2 prevents hard disk driver (ACSI) load 
automatically. I tested it with TOS 1.4 and 2.06.

Now executable bootsector from floppy image will be executed if 
'Boot FI' (boot from image) is checked. Because some images
 have there code which blocks mounting (false virus detection, 
destroying of RAMdisk) it is initially turned off. For most, it will be OK
. Smaller part of images starts from bootsector, most has start from 
AUTO folder - AUTO programs execute from RAMdisk
 (mounted as floppy A). Load is of course much faster.
After playing you usually press reset to finish it - RAM config usually
will remain same - with occupied 1MB, but no need for hard reset to clean
machine up before mounting another image - program will mount it on
same place.
When want to back on regular hard disk usage you need to remove extra
RAM occupation - ALT+Right Shift+CTRL+Del will do hard reset.
 It will work on TOS 1.4 and  above. Shortly after pressing reset button 
you can always do it (except few games). Or use button CLEAR...  in IMGRUL.
Program will work on TOS 1.4 and later (1.02 crashes for now). 
Program installs (maps) (logical) drive B (whether it is present or not) to real
 drive A - may be good for saving and keeping positions. 
Min 2MB RAM is required for usual floppy images of 720-900KB. 

Notes about reasons why many game will not run:
If game or it's loader uses any direct floppy access (hardware access)
 it will not run.  In such cases you need to write image on floppy, 
and run from. Most success may expect with cracked and FILED
 games. If you see floppy LED activity after reset or game start for
 longer time, no help, must write on floppy.

Setting (checking) '16MHz MSTE' has sense only for Mega STE machine.
 Other STs will crash after reboot if is checked. 16MHz means faster run 
(graphic) for games, but not all will like it.

This concept is good for single floppy games , but not for games on more
 floppies. In theory, it is possible too, but is complicated to code and usage,
 and many of such games is ready for run/installing from/on hard disks.

Send test results, comments on this mail:

pp@ppest.org 
