Re: Ada and Hardware

["Kretschmer, Matthias" <herrchen@uni-bonn.de>]

"chris.danx" wrote:
> 
> "Tarjei T. Jensen" <tarjei.jensen@kvaerner.com> wrote in message
> news:9de8t0$e1s3@news.kvaerner.com...
> >
> > chris.danx wrote :
> > >I don't understand FAT12 yet, and it complicates the boot sector.  Also the
> > fs
> > >can be messed with if it's a fat12 disk easily.  I don't want this.  Would
> > you
> > >want any person coming along and swapping a driver file for another that's
> > got a
> > >similar signiture but does malicious things behind the scenes?  What's more
> > >anyone can come along and delete a critical file easy.  Two clicks and OS
> > is
> > >gone.
> >
> > That situation is no worse than anything else that boots from a standard
> > msdos floppy. If I thought it would be a problem II would  make he file(s)
> > invisible (system).
> >
> 
> This is true, but my main reason for doing it with BFS instead of FAT12 is the
> simplicity of working with the files on it.  The Boot sector is simplified
> grately and so too is the secondary loader (a 32bit Ada loader with floppy
> driver; the OS will have a new module reconfiguration system which is easier to
> manage with Ada than ASM).  I want to limit my use of ASM in the system to the
> bootsector if possible.  Everything else stands a good chance of being Ada or
> maybe a teensy bit of C.
> 

If you want to implement real usefull memory-management you need to
develop at least some glue in Assembler (there are things that can't be
really done in C or has anybody yet seen an LGDTR mnenomic in C?).

> > >I know how to boot from a floppy for the file system i'm using.  It's
> > really
> > >easy (just look in 2nd inode to get address of primary kernel file, and
> > >calculate offset).  I just need to get the files from my FAT hard disk to
> > my BFS
> > >floppy.  The current driver implements a disk as a file on a HD, and it's
> > really
> > >easy to work with.  The problem is i need to create a bfs enabled disk,
> > write
> > >files to it, read info from it, via an interactive shell.  I don't know how
> > to
> > >do this in Ada (i can do the shell though).  I do know how in C.
> >
> > If you know how to do it in C, you know how to do it in Ada.
> 
> I'll try a binding to C and see how it goes.

maybe you work with your disk on the hdd and than just put the image on
floppy? - using your driver you put on your floppy running Win98 should
be a problem, because win32 applications shouldn't be allowed to
directly access hardware (but I am no Windows expert and I wouldn't
wonder if M$ made it possible).

mfg M.K.