Re: MS-DOS 3.30 boot on the CBM-II

From: william degnan <billdegnan_at_gmail.com>
Date: Sat, 4 Nov 2017 10:03:15 -0400
Message-ID: <CABGJBuegWTUXzER90rQDtDJt1wmF8rQUb6eWPkM1T3-ukxAhJQ@mail.gmail.com>
I am happy to help test.  I have DOS 1.25 and can boot into it with my CBM
II, but I'd need an 8050 image of anything else that's needed.  I prefer if
possible to start with an image of a working 3.3 disk so I can start at the
testing the software part not the figuring out how to get it ruuning all
weekend :-)
Bill

On Sat, Nov 4, 2017 at 9:51 AM, Mia Magnusson <mia@plea.se> wrote:

> Den Sat, 04 Nov 2017 11:38:42 +0100 skrev Michał Pleban
> <lists@michau.name>:
> > smf wrote:
> >
> > > Are you planning on removing the need to boot msdos 1.25 first?
> >
> > Yes, that's the plan. However, I need first to figure out how to issue
> > the initial "boot system" command from the 6509 to 8088, something I
> > haven't tackled yet.
>
> I assume that involves disassembling both the 8088 ROM and the 6509
> software. Maybe someone else could step in here if it's just too much
> for one person?
>
> (Unfortunitely I don't own any CBM-II so I can only be of theoretical
> help :( )
>
> > Also, first I would like to make a ROMmable version that can be placed
> > in the EPROM chip on the board, but I am running out of space now (the
> > ROM has only little than 3 kB free space).
>
> First: It is so cool that you have come so far with this project!
>
> Re the rom, it seems like the whole upper 64k is decoded to the rom,
> and nothing else resides there, so with just an adapter and some extra
> wires it should be possible to have up to 64k rom.
>
> Perhaps it would be a good idea to make a simple board with both ROM
> and 64k RAM and some way to switch between ROM and RAM when reading
> from the upper 64k. PB7 of the PC side CIA seems to be NC according to
> the schematics, so that port could be used to switch between RAM and
> ROM.
>
> This could work as a developement thing, and when things will be more
> or less finalized it could be replaced by a larger ROM. With 64k ROM it
> might even be a good idea to have a ROM disk for some of the most used
> files, i.e. COMMAND.COM from the DOS version a user prefers to run.
>
> --
> (\_/) Copy the bunny to your mails to help
> (O.o) him achieve world domination.
> (> <) Come join the dark side.
> /_|_\ We have cookies.
>
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>


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Received on 2017-11-04 15:00:02

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