Re: Upcoming project: virtual hard drive for //c and IIgs

[pitz <pitz.wong@gmail.com>]

On Apr 26, 5:47 pm, IUnknown <stevement...@gmail.com> wrote:
> On Apr 26, 10:30 am, Steven Hirsch <snhir...@gmail.com> wrote:
>
>
>
> > Peltier Cedric wrote:
> > >> There are plenty of examples out there showing how such a driver might
> > >> be done for Linux.  Poke around for sio2pc (Atari) and Drivewire
> > >> (Tandy CoCo).
>
> > > Maybe a driver for the smartbus is possible under linux, but I don't
> > > know if we could sample reliably a 250KHz serial line through even
> > > modern PC I/O under a multitasking environnement (I will give it a try)
> > > without a dedicated hardware. From my point of view, using such
> > > dedicated hardware on a modern system look pointless for the task,
> > > better to do a stand alone system from scratch interfacing the smartbus
> > > to IDE or SD. I hope I exposed constraints clearly.
>
> > I don't know enough about the smartbus protocol to speak authoritatively, but
> > the parallel port hardware on more recent systems should be capable of 1Mhz.
> > operation.  How tight are the timing margins?  Where can I find a timing
> > diagram for the bus?
>
> > If it could be done with a small amount of logic or FPGA, that would still be
> > of interest to me.
>
> > Steve
>
> I have always wondered about a 'virtual hard drive' project like
> this.....  Using some sort of serial connection.
>
> The IDE/CF adapters for the IIgs devices are cool, but they are far
> too expensive for the hobbyist.
>
> Serial ports can be added to any PC or MAC with a $10 USB->DB9
> adapter. The IIgs has built-in serial ports, but I don't think it is
> possible to 'boot' from one.....
>
> It wonder if it would be possible to throw together an *extremely*
> simple card for the IIgs that hooked into the boot sequence enough to
> control a simple onboard UART....   and talked to a 'host' at the
> other end of the cable...
>
> Even at 56kbps operation, which should be pretty easy to obtain... it
> would be plenty fast for most operations...  Sure, you could use a
> parallel connection, but I wonder if the extra wires and component
> costs would be worth the speed advantage.
>
> The software to drive it could be written in a cross-platform language
> like java or C#/.NET ... the hard part would be interfacing with the
> USB serial port on the host... The rest of the host code would be
> pretty trivial.
>
> Too bad that I am not an electrical engineer....    :)

If a custom box can be programmed to read/write the AppleShare
protocol and has a LocalTalk port (which needs a faster rate than that
provided by a serial port), then it could theoretically boot the IIgs
(without the need of a card) by configuring the IIgs to boot from one
of the LocalTalk slots.