Re: [hatari-devel] Attaching an ACSI harddisk: 3 x Why

> Thomas Huth <th.huth@xxxxxx> hat am 12. März 2015 um 21:17 geschrieben:
>
>
> Am Thu, 12 Mar 2015 00:09:18 +0200
> schrieb Eero Tamminen <oak@xxxxxxxxxxxxxx>:
>
> > Hi,
> >
> > On keskiviikko 11 maaliskuu 2015, perot@xxxxxxxxxxxxxxx wrote:
> > > I'm wondering why Hatari should require a reboot if a harddisk
> > > image is attached? It does not (of course) if a floppy image is
> > > attached. So why with a harddisk? With real hardware, you could
> > > have switched on your (for instance) Mega ST, and switch on the
> > > (for instance) SH205, since it's a separate unit, only after the
> > > Mega ST has come up with the desktop.
> > >
> > > I have been coding software, including hardware emulators, for over
> > > 30 years, but cannot imagine any solid reason for this restriction.
> >
> > None of the Hatari developers or users has been interested enough
> > to add support for that. Contributions from interested people are
> > are welcome. There are some other less often used ACSI/IDE fatures
> > which emulation is missing.
>
> ... and as far as I know, the original ACSI bus was also not
> "officially" hot-pluggable.
> If that worked for you, Peter, that's fine, but I think you could also
> have easily destroyed your hardware that way.

I'm not talking about hot-plugging. I'm talking about "hot-switching-on", which is a very different thing. Ground lines are connected before and after switching. Since the devices have a power switch each, the exact switch-on sequence is undefined anyway. Many people used to switch both at the same time using a switching power stripe. The ST might come up without the HD but pressing the RST button fixes that. I've been through all the hardware details, I'm 100% sure this is safe.

I used a different way to solve the original problem. I edited the image using hexeditor, changing the name of the AUTO folder to EUTO. Hatari booted the image happily, and I could sort out the offending AUTO programs.

Unfortunately I found Hatari is not able to support the enhanced screen resolution that I had on that machine. Well - to be honest - it was to be expected. The original machine was an ST that I had rigged for 16MHz. That needed a 16MHz rated 68000, but all the other ST internals accepted the higher clock just fine. For the FDC I built a drive operated switch between 8 and 16MHz to support HD floppies, and another small PCBA generated new video sync signals that were accepted by GLUE and VideoShifter to display a 960x544 desktop on an SM124. Found only the oldest SM124 would tolerate this.

Once I find some time nostalgia might drive me to implement support for this into Hatari. I don't think though too many people have any use for it.

Cheers Peter

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