[BBC-Micro] Fw: DD & HD Floppies

Dave Curran bbc at pdcurran.co.uk
Sun Oct 17 10:42:06 BST 2010


Fair point, that though hit me after I had posted.

But it's not like it hasn't happened before. Just as the 8271 was replaced
by the plug in 1770 replacement, why not a plug in module with a controller
capable of using the standard 1.44M drives. These days it should be possible
to get a small microcontroller to do an impersonation of the relevant
controller, with added capabilities. Just a pic on a module to droped into
the 8271 socket on a bbc, more of an issue for the master though. The 1770
is quite will documented, and the floppy interface seems reasonably straight
forward. It doesn't sound unreasonable?

Dave

On 17 October 2010 10:25, Bob Devries <devries.bob at gmail.com> wrote:

> Dave,
>
> I think that neither of the floppy disc chips used in the BBC are capable
> of
> the double data rate.
>
> Regards, Bob Devries
>
> ----- Original Message -----
> From: "Dave Curran" <bbc at pdcurran.co.uk>
> To: <bbc-micro at lists.cloud9.co.uk>
> Sent: Sunday, October 17, 2010 6:36 PM
> Subject: Re: [BBC-Micro] Fw: DD & HD Floppies
>
>
> > Silly question, but I'm just taking a step back from this and thinking
> > that
> > instead of adapting HD disks to work in DD drives, what are the chances
> of
> > getting standard 1.44M HD drives to work on the BBC?
> >
> > There are probably good reasons why this hasn't happened, just wondering
> > if
> > any of them weren't insurmountable. I know there are likely to be issues
> > with the smaller heads used in HD drives when writing DD disks to be read
> > on
> > DD drives, the same sort of issues that causes all the fun with 40 track
> > disks written by 80 track drives. Are there also issues with catalogue
> > sizes
> > or track counts?
> >
> > The ideal would be adapting one of the DFS's to work with 1.44M disks -
> > unless any of them do already? Otherwise some hardware mod to use HD
> > drives
> > and disks as if they were DD drives and disks. Double all the track steps
> > and perhaps even repeat every write on the next track to increase the
> > chances of DD compatibility?
> >
> > Just a thought?
> >
> > Dave
> >
> > On 17 October 2010 05:33, Rick Murray <rick at rs432.net> wrote:
> >
> >> On 17/10/2010 06:19, Kieran Mockford wrote:
> >>
> >> > http://www.floppydisks.com
> >>
> >> Nice to see somebody still keeping the floppy alive. But, what, no 8"?
> >> <giggle>
> >>
> >>
> >> > There doesn't seem to be anything that indicates that they won't ship
> >> > to
> >> > that side of the pond (this side gets free shipping, though!).
> >>
> >> I went to perform a pretend-purchase of 20 5.25s to see what sort of
> >> shipping would be involved. The site tries to pass you over to Google
> >> Checkout, at which point NoScript put its foot down:
> >> --8<--------
> >> [NoScript XSS] Sanitised suspicious upload to
> >> [
> >>
> https://checkout.google.com/api/checkout/v2/checkoutForm/Merchant/655251604398233
> >> ]
> >> from [http://www.floppydisks.com/view_cart.php]: transformed into a
> >> download-only GET request.
> >> --8<--------
> >>
> >> Funny. The place I get Japanese food from works fine with its bank, my
> >> geek-bits site works fine with its banking service. Hell, even EDF works
> >> when it passes you all over the place. But this one triggers NoScript.
> >> Probably okay, but I'm paranoid when it comes to my credit card info and
> >> the Internet... and if they can't get this itty-bitty detail right.....
> >>
> >>
> >> Best wishes,
> >>
> >> Rick.
> >>
> >> --
> >> Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
> >> BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
> >> E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...
> >>
> >>
> >>
> >> _______________________________________________
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> >> bbc-micro at lists.cloud9.co.uk
> >> http://lists.cloud9.co.uk/mailman/listinfo/bbc-micro
> >>
> >
>
>
>
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