[Coco] VHD 256 or 255 disks

[Bill Pierce]

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
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-----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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