[Coco] Orchestra90-Dragon NEW version

Pere psergm at gmail.com
Wed Jul 20 09:43:30 EDT 2016

Hello Barry,
I have tried to answer to your private e-mail but my messages
get always a warning that they are delayed and maybe not sent ...
So, I prefer to copy here my last answer about the files that don't
score correct on Orchestra90.
Hello Barry,
I am sorry you cannot use these disks ...
You could 'repair' the scores that give problems when you
press the 'S' (score command).
If you press 'E' (edit command) the text changes color and
the cursor goes to the 'wrong' character.
Usually these errors arise because the score was not written
for Orchestra-90 but for Piano-85 or similar ...
There are THREE kind of errors that can be solved:
1) If the cursor goes next to a chars combination that reads like
"JATx" being x a number, you just ERASE the FOUR chars
This is done having the cursor at the first char (J) and pressing
at the same time Shift and Left Arrow (once for every char)
2) If cursor goes to a 'L' char or at the char at its right, you just
have to delete both. I mean EVERYTIME you see a letter 'L'
you can be sure it is an error and have to delete it, but remember
you MUST always delete two chars, the L and next one!
3) Finally you will find errors because converting the score to
Orchestra, the comments were longer than 32 chars and the text
uses more tan one line and the second one is not commented.
In this case, create a space (Shift + right arrow) and put a '/'
on the first char on the left.

Whith these tricks you will recover all of the scores that were
not ment to be played with Orchestra-90.
Other errors need consulting the manual and not always are
easy to repair, in these cases we have deleted the score.


; ------------------------------------------------------------------------------------
-----Mensaje original----- 
Message: 1
Date: Sun, 17 Jul 2016 02:30:45 -0400
From: Barry Nelson <barry.nelson at amobiledevice.com>
To: coco at maltedmedia.com
Subject: Re: [Coco] Orchestra90-Dragon NEW version
Message-ID: <6925C45C-CEA2-4E9E-B7FB-F4A30F7B5400 at amobiledevice.com>
Content-Type: text/plain; charset=windows-1252

I would be using a CoCo SDC since Orchestra 90 talks directly to the disk 
controller hardware. It looks like the CoCo SDC has at least some support 
for the VDK format…


DSK Images
The DSK image format is named for the extension most commonly appearing on 
such files. Images in this format consist of a simple sector array with each 
sector being 256 bytes in length. This is the most common format used in the 
CoCo world. It is sometimes also referred to as the JVC format although that 
format allows for an optional header to precede the sector array. The CoCo 
SDC will recognize a JVC header only for the purpose of identifying the 
number of sides.

In order to be recognized as a simple DSK image, the file size must be an 
exact multiple of 256 bytes. The minimum file size is 82,944 bytes which is 
equal to 324 sectors or 18 tracks of a single-sided CoCo disk (enough to 
accommodate the Disk Basic directory track). If the file size is not a 
multiple of 256 then it is assumed the image contains either a JVC or VDK 
(Dragon) header. A sanity check of the header bytes is performed to 
determine if the file can be used.

The disk geometry associated with a DSK image is determined by the file 
size. For floppy images the number of sectors per track is always 18. There 
are either one or two tracks per cylinder (equal to the number of sides) and 
a maximum of 80 cylinders. The largest file size for a floppy image is 
737,280 bytes or 2880 sectors (double-sided 80 cylinders).

An image with more than 2880 sectors is considered to be a hard disk. If a 
hard disk image is accessed using the floppy interface mode, only the first 
1440 sectors can be used. In this situation those sectors are accessible as 
a single-sided 80 track floppy disk. The controller's LBA interface mode 
must be used to access sectors beyond the first 1440 in a hard disk image.

> Bill Pierce ooogalapasooo at aol.com
> Sat Jul 16 18:50:09 EDT 2016
> Barry, I think you'll have problems with VDK in DW4 and/or VCC. I have no 
> idea whether Mess even supports VDK at all. I have had many problems with 
> VDK in VCC as well as DW4.
> VCC and DW4 both only have "limited" VDK support and will not read all 
> forms of VDK. I may be wrong and those disk images may read fine, though I 
> think the best bet would be to load the VDK images into XRoar and copy the 
> files to a JVC format disk image.
> XRoar originally only supported VDK and it's still the native format, but 
> JVC support has been greatly improved on the later versions of XRoar.
> In the end, VDK is actually a more "complete" disk image format, having 
> the "between track" timing sections and such, but JVC with it's straight 
> "raw file" format is just easier to work with and the reason they became 
> the standard for VCC & DW4. Even the NitrOS9 repo produces JVC style disk 
> images.

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