[Coco] Software testing for FDC emulator

[John Donaldson]

RE:.....The program (which is an ml one) uses the Index Hole timing pulse to 
read disks with its own disk I/O routines.


There is the problem. When non-standard IO calls are made then yes emulated Disk 
operation is at risk. 


John Donaldson




________________________________
From: Robert Gault <robert.gault at att.net>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Mon, April 25, 2011 8:46:09 AM
Subject: Re: [Coco] Software testing for FDC emulator

Aaron Wolfe wrote:
>> 
>> Everyone already knows that these virtual drive systems don't fully emulate
>> the floppy controller hardware but what the average user accomplishes with
> 
> This is the point I'm trying to make.. everyone does not know.  It's
> only when they go to play that favorite game from years past and
> discover it doesn't work that they come to realize this.  After
> helping people who've run into this very issue (and feeling bad for
> them but not being able to do anything), I think it's our
> responsibility to make it very clear that there are some limitations
> with these types of systems.  When we say things like "behaves just
> like the FDC" it is easy to see how a user can be confused.
> 

Here is an example of just how tricky this can be.

One of the programs that will not work with Drivewire or CoCoNet is the 7th 
Link. Darren has been using this for testing purposes. The program (which is an 
ml one) uses the Index Hole timing pulse to read disks with its own disk I/O 
routines.
The program is on a .dmk image so the hardware format of the disk is correctly 
emulated. In general, MESS can read these disks. In fact the game will play on 
MESS with any version older than 136b. That version altered the wd17xx routine 
such that the "drives" don't wake up soon enough after receiving Motor On / Head 
Load commands. The game thus starts reading graphics data too late resulting in 
the screen left/right edges displayed in the middle of the screen with 
wrap-around.

This is an example of an issue beyond the scope of Drivewire or CoCoNet. It 
would not help in the least if the .dmk format was supported by these servers as 
the Coco ROM routines are not being used.

--
Coco mailing list
Coco at maltedmedia.com
http://five.pairlist.net/mailman/listinfo/coco