[Coco] CoCo Disk Drives

[Michael Brant]

Robert and Brian thanks very much. I am quite new to using more than one
floppy of any kind on a CoCo. back in the old days, I had a CoCo2 with just
one physical drive.

On Fri, Mar 13, 2015 at 10:30 AM, Robert Gault <robert.gault at att.net> wrote:

> Brian Blake wrote:
>
>> Robert will correct me if I'm wrong, but, when issue the drive off
>> command,
>> it disables the DW access to floppies 0-4. Floppies 5 to 255 should still
>> be available to DriveWire.
>>
>>
> Exactly as already was stated. :)
>
> If you want both floppies and Drivewire mounts, you should generally not
> mount any disks in the Drivewire 0 and 1 positions as you want drives 0 and
> 1 to be floppies.
>
> Now things get more complicated if your hardware floppy drives are double
> sided and you want to use double sided disks. You also need to know what
> the default drive mask table values are for HDBDOS. You can find them in
> the HDBDOS source code and they are 1,2,$41,$42.
> These values mean the the front sides of each hardware floppy are drive0
> and drive1 while the respective back sides are drive2 and drive3. So for
> complete access to the floppies, enter DRIVE OFF and drives 0-3 will be
> floppies and drives 4-255 will be on Drivewire.
>
> Now you don't have to enter the DRIVE ON/OFF commands if you use some
> tricks to automate things. You could also use a menu program where you can
> select what you want with a key stroke.
> Remember I said the HDBDOS by default start with drives 0-255 on Drivewire
> or a hard drive. It will also automatically look for a Basic program
> AUTOEXEC.BAS on drive0 and, if found, will run it.
> The program can be a menu or just a simple command. In your case you might
> want a one liner: 10 DRIVE OFF . Then any time you start your system with
> both your PC, Drivewire, and then the Coco running, you will automatically
> get the DRIVE OFF command and will have your floppies active. If you will
> only be using single sided floppies make the command: 10 DRIVE OFF 1 . Then
> you will have the front side of both floppies and Drivewire for 3-255.
>
> Now that's not all you can do. If you don't want to use Basic, you can
> automatically boot NitrOS-9. In that case, you would mount a NitrOS-9
> bootable disk on DW 4, either a .dsk or .vhd. The .dsk in DW0 would be a
> Basic disk with AUTOEXEC.BAS having  10 DOS4 . That would try to boot
> NitrOS-9 from DW4.
> If you want to mount a .vhd type used with VCC or MESS that has the boot
> disk on a Basic drive say 254, that needs a slightly different approach.
> The simplest method would require an HDBDOS ROM with an offset of $5A000
> and the .vhd mounted in DW0. The AUTOEXEC.BAS on the .vhd could be 10 DOSn
> where n is the drive on the .vhd where the boot disk is located.
> Keep in mind that you must have a BOOT and /DD set for a Drivewire system.
>
> A third alternate to permit using the standard MESS or VCC .vhd drive
> without requiring any changes to the .vhd would be to create a floppy boot
> disk for Drivewire and mount it in DW1. The floppy in DW0 would have  10
> DOS1 , the BOOT on DW1 would be set for drive1, and the /DD descriptor
> would be equivalent to /X1.
>
> Now if you want only Disk Basic and not NitrOS-9, you can still use a MESS
> VCC .vhd but need to place an offset value in the DW drive number of $5A000.
>
>
> Robert
>
>
>
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