desoldering problems and technique (and amiga 2000 mod)

Ethan Dicks ethan.dicks at gmail.com
Mon Jan 4 13:20:45 CST 2010


On Mon, Jan 4, 2010 at 1:31 PM, Brian Lanning <brianlanning at gmail.com> wrote:
> What do you want for one?

I've been selling them at $99 each, single quantities, with quantity
discounts starting at q.5 to encourage groups to buy (with combined
shipping, naturally).

> Although I probably can't use it at the moment since I have a 286
> bridgeboard.  It would still be nice to play with one.

It's a good solid design, and the only real problem is Zorro II
caching - not a problem with 68000s, naturally, and Enforcer works
fine with '020 and '030 and most '040 boards.  I think Enforcer works
with some or most '060 boards, but since it interferes with most of
the caching parameters, it robs the machine of most of its performance
advantage.

>> Essentially, there's drivers for IDE disks (yawn),
>
> IDE is a bigger deal now than you might think.  I have a buddha board
> which is basically an IDE controller in a zorro 2 slot.  Works great.
> But if you could package one of your bridge boards with a throw-away
> generic ide/port combo board, a network board, and a driver disk, (you
> should throw in a compact flash to IDE adapter also) I bet you'd get
> quite a few takers on the amiga boards.

Perhaps, and the Flash adapter is a good idea, but the limitation is
that the IDE interface is old-school 16-bits-at-a-time-no-DMA, so
really slow, and there's a definite limitation on disk size (I forget
exactly, but probably around 1GB or so).

> 10baseT on the 2000 is not so cheap these days either.

It's not, and that's been the bread-and-butter of this design.

> The ability to read/write to high density
> floppy drives from that ide controller would be welcome too.

Not possible.  The Amiga lacks onboard DMA channels and this board
does not provide any.  No ISA DMA is supported.

> Could you auto-boot the ide disk?

Not without boot ROMs that knew what to do with it, so no.  The GG2
Bus+ implements AUTOCONFIG with a GAL, not an EPROM, so it'd be a
major change to support booting.  Because of the non-DMA and the disk
size, I don't think it's a desirable-enough feature to warrant a
design change.

> Anyone with a 68060 processor board is likely to have a mediator
> anyway, which means PCI slots.

Long ago, there were plenty of A4000s with '060 boards.  Those were
the folks that weren't viable customers.  These days, anyone with PCI
slots isn't going to care about an ISA adapter.

The sweet spot for the GG2 Bus+ is an A2000 or lightly-loaded A3000 or
unexpanded A4000.  Most people aren't willing to drop the money on a
network card for those machines, so unless you have a burning need to
add a couple of serial ports or open up your Amiga parallel port for a
digitizer and still want to attach a local Centronics printer, the GG2
Bus+ is probably not particularly desirable, thus the sales cliff 8-9
years ago.

-ethan



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