[Coco] VHD 256 or 255 disks

[S Klammer]

Could there be agreement made for a VHD2 format?  Add whatever bytes at the
end to specify what offsets (etc) are used by OS9 and RSDOS.   Being at the
end, they wouldn't mess with existing environs if they fit.  If those bytes
contained fixed header/trailer bytes we'd be reasonably certain that the
bytes inbetween were in fact the offsets described within...

sk
On Oct 20, 2013 10:34 PM, "Bill Pierce" <ooogalapasooo at aol.com> wrote:

>
> Nick,
> I think the real problem is that no one has stuck to any sort of standard
> and they all kind of "do things their own way", therefore trying to explain
> how to use everyone else's idea of how to use a vhd would make an expansive
> book that still probably wouldn't cover the offset or format of the very
> vhd you're tring to use.
>
> Alan Dekok (I think) set the standard in the beginning for the VHDs being
> used with the emulators to have an OS9 partition with the size of $5A000
> bytes, then continuing with 256 rsdos disks. This format sets the
> rgbdos/hdbdos offset at $5A000. Then there were those who didn't want the
> OS9 partition and set the offsets to 0 with only a RSDOS partition, then
> came the ones who didn't use rsdos and wanted just an os9 partiton with no
> rsdos partition.... Then came the CF cards with their VHDs and even odder
> partiton offsets.
> So basically, any kind of standard went out the door.
>
> Personally, I use the original $5A000 size OS9 partition followed by 256
> rsdos disks as this was the standrd for the original Vcc virtual hard
> drive. Since I work with both real Cocos w/DW4, XRoar w/DW4, and Vcc w/Dw4,
> it gives me a standard across both realms and I can switch drives instantly
> between DW4 instances to move files or disks back and forth between Vcc,
> XRoar, the Coco 3, and the Coco 1.
>
> Then there's the Drivewire offset... The only problem with using the drive
> offset in drivewire instead of hdbdos, is that the offset is applied to the
> o9 partition as well as the rsdos partition making the os9 section
> unreadable. I know there's ways around this, but in a nutshell.... it's
> nuts :-)
>
> Bill Pierce
> My Music from the Tandy/Radio Shack Color Computer 2 & 3
> https://sites.google.com/site/dabarnstudio/
> Co-Webmaster of The TRS-80 Color Computer Archive
> http://www.colorcomputerarchive.com/
> Co-Contributor, Co-Editor for CocoPedia
> http://www.cocopedia.com/wiki/index.php/Main_Page
> E-Mail: ooogalapasooo at aol.com
>
>
>
>
> -----Original Message-----
> From: nickma <nickma at optusnet.com.au>
> To: CoCoList <coco at maltedmedia.com>
> Sent: Sun, Oct 20, 2013 9:16 pm
> Subject: [Coco] VHD 256 or 255 disks
>
>
>
> There seems to be a lot of confusion about how Virtual Hard Drives
> work, me included, that I wonder how many people have been turned off
> from using them and learning about OS-9.
>
> Maybe this is an opportunity for someone to develop a small book about
> Hard Drives on the CoCo with emphasis on the VHD and Drivewire.
>
> I'd be prepared to buy such a book if it was clearly written and takes
> the mystery and frustration out of the whole process and gets people
> back on track to producing software rather than fighting to make
> everything work in the first place.
>
> Nick
>
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