Re: Multitasking during disc access (was: Re: MiNT scheduling)

[Sven Karlsson <sven@it.lth.se>]

>The various functions
> you hook into the kernel via the XFS/XDD-interface doesn't return
> until they've done their stuff (e.g. read/written some stuff), and
> AFAIK they do it in supervisor-mode. And all (x)bios-functions runs in
> supervisor-mode for sure, so even changing MiNT won't work without
> rewriting the (x)bios... 

It is quite possible to write nonblocking scsi/ide/floppy etc
routines that for instance minixfs can use. There is nothing in
the current driver/filesystem handling that prevent that.
However to be efficient a couple of things need to be implemented:

1) New lowlevel routs (ie hard disc drivers etc) that 
   replace bios/xbios routs completely
2) New TOS/FAT fs since a lot of ppl still use these
   systems.
3) Slightly modify minixfs so that it take advantage of
   nonblocking calls better.
4) Implement a proper sector cache with delayed write
   capabilities.

Neither of these routines are very hard to write but since
the danger of corrupting a volume is present they must
be carefully tested. I think it would take about 6 months
to get them all right. In which time there hopefully will
be about three Fenix versions.

Regards
 Sven