[Coco] working with physical floppy drives under NitrOS-9 via DriveWire

[Kip Koon]

Hi Chris,
When I first started working with NitrOS-9 and Drivewire 4, I was running a Coco3, MPI, Hard Drive Specialist Floppy controller (compatible with Tandy's Floppy Controllers), SuperIDE Controller and one other cartridge of what kind I don't remember and 3 - 3.5" 1.44MB floppy drives used as 720KB drives.  I covered up the DD/HD hole to force 720KB capacities.  Whenever I booted NitrOS-9 from my floppy drive 0, I could access my floppies fine.  I added Drivewire 4 to the mix and when I booted from floppy drive 0, I could access both Drivewire drives and floppy drives just fine.  When I started being able to boot NitrOS-9 off my SuperIDE controller, I could no longer access my floppy drives from NitrOS-9 even though the virtual (or real) hard drive was accessible as were the Drivewire drives.  Now this really puzzled me!  I went round and round with this for quite a while.  
Then I remembered that the chip select line for the eprom was independently controlled from the rest of the electronics in the same cartridge at address $FF7F.  Of the 8 bits at $FF7F, Bits 0 & 1 control the SCS line and Bits 2 & 3 control the CTS line if memory serves correctly.  Bits 4 - 7 are not connected therefore they are "Don't Cares".  With my SuperIDE Controller in Slot 3 and my Hard Drive Specialist Floppy Controller in Slot 4, the MPI switch on Slot 3 and before booting NitrOS-9, in DECB or HDB-DOS I would "POKE &HFF7F,&H23" which would use the rom or eprom in slot 3 on the SuperIDE controller and activate the floppy controller in Slot 4.  In DECB this worked fine.  Now if using HDB-DOS one more BASIC statement must be used and that was "DRIVE OFF".  Since I have 3 - 720KB 3.5" double sided double density (DSDD) floppy drives, I just activated all my floppy drives by deactivating the first 4 Drivewire 4 drives 0 - 3 with the "DRIVE OFF" HDB-DOS BASIC command.  Then by entering DOS or DOS0 I could automatically boot a floppy dsk image in Drivewire 4 drive 0 and use all my drives in my MPI.  
In this configuration, I could boot off the compact flash card as /I0 and access the hard drive as /I1 in the SuperIDE Controller in Slot 3 and still use the floppies as /D0, /D1 & /D2 on the floppy controller in Slot 4.  That was 4 or 5 years ago.  I have since brought up NitrOS-9 on various configurations the most recent being the CocoSDC.  I LOVE the CoCoSDC!  Once it is setup correctly, booting NitrOS-9 is really a snap and the Floppy issue no longer exists.  By the way, NitrOS-9 boots considerably faster on the CoCoSDC that ANY other way!  Again, I Love it!  Somehow, the way Darren designed the hardware in the CoCoSDC and the SDC-DOS software, it makes the "POKE &HFF7F,&H23" for my Coco3 configuration obsolete as well as the "DRIVE OFF" command.  Of course this is not HDB-DOS either.  :)  
How about sending me a private email and I will be happy to help you get your Floppies going under NitrOS-9.  Since I started back using my Cocos again and NitrOS-9, I have made more NitrOS-9 boot disks for my friends and myself than I care to count so I'm sure together we will be able to get you up and running.  Take care my friend.

Kip Koon
computerdoc at sc.rr.com
http://www.cocopedia.com/wiki/index.php/Kip_Koon



> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Chris Oliver
> Sent: Sunday, October 18, 2015 10:22 AM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] working with physical floppy drives under NitrOS-9 via DriveWire
> 
> All — To clarify my use case:
> I want to be able to boot to NitrOS-9 and run it from DriveWire — while using my two physical floppy drives.  (Basically running the OS
> from a virtual drive, while physically accessing the floppy drives tied to my 3029 controller.) Problem I’m having is chicken/egg I think.
> Currently I need to load HDB-DOS in order to DOS the NitrOS-9 image on DriveWire.  Once DriveWire loads up, I believe it overwrites
> HDB-DOS (doesn’t it?).  And then I need a path to the physical floppies — meaning I then have to switch over to slot 4 on the MPI
> (where the controller lives).  After that switch to slot 4, doing things like directory listings and format commands (from NitrOS-9 via
> DriveWire to my physical /d0 drive) does cause the drive to spin up, and the read/seek head does attempt to do something (makes
> some very different sounds than normal, though) — but all such commands end in error codes.  A format of /d0, for example, gets to
> the stage of naming the disk before it dumps out with an error. Dir commands result in errors without even partial listings.
> So the real question is: Does NitrOS-9 — running via DriveWire (not via a physical boot disk) - have the ability to access the physical
> floppy drives via the 3029 controller.  And if so, how can you boot to the OS on DriveWire (which seems to require HDB-DOS), while at
> the same time providing access to the controller (which is tied to slot 4 in the MPI).  And in a scheme like this — which elements
> remain resident (vs. being overwritten by others)?
> Hope this helps explain it better — I’m probably missing something obvious here.  :) Thanks to all!
> Chris
> -----
> All,
> 
> I leverage HDB-DOS (burned onto an eprom in slot 1 of the MPI) to DOS to the latest Coco1 NitrOS-9 disk image (that has been loaded
> into the Disk 0 slot in DriveWire).  Loads up great.  Can work with virtual drives (/X1, etc.) perfectly fine.
> 
> So — now I want to be able to access the physical floppies.  I have the orig 3029 Tandy controller, with a pair of the orig Tandy floppy
> drives.  Is there any way to run NitrOS-9 via DriveWire, and yet be able format and use physical floppies?  Would be great if I wasn’t
> restricted to virtual drives…
> 
> Very curious — let me know!
> 
> Chris
> 
> 
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