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

[IUnknown <stevementzer@gmail.com>]

On Apr 26, 5:55 pm, pitz <pitz.w...@gmail.com> wrote:
> 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.- Hide quoted text -
>
> - Show quoted text -

As I understand it, the appleshare/appletalk port on a IIgs requires
custom hardware to handle the encoding/decoding of the signals.

Or is it just a standard UART with a high data rate and special logic/
firmware to handle the decoding?