On Jul 29, 11:10 am, hartonj <[email protected]> wrote:
> Well, it helps to have access to the SCSI specifications, which are
> not free and may not be available. If anyone could reproduce this 
> ->http://micha.freeshell.org/pcmcia_drive/index.phpit could be
> interesting. Presumably a CF to PCMCIA adapter could be used in such a
> device. It would probably be of more benefit if someone could figure
> out how to boot Mac OS from a LC PDS/Nubus/PCI drive controller. Then
> you could use any kind of drive available provided that you could get
> an appropriate controller built for your expansion slot.
>
> http://68kmla.org/wiki/SCSI_hard_disk_replacement_options

I have some of the SCSI documents here:
<http://www.prismnet.com/~trag/Standards/>

Unless someone is going to do all the design and assembly free of
charge, one quickly finds that the unit price of these projects
quickly approaches the price of what is commercially available.

Even if you assume there is a market for 100 of something, the printed
circuit board alone will still run $10 - $20 (depending on size and
layers).   Add some kind of microcontroller or FPGA for another $10.
Connectors, either SCSI or PDS can add up.   And then one usually
finds that there are a handful of other chips at $.50 to $2 each that
are needed to tweak and/or isolate the buses, and before you know it
the parts alone are up in the $30 - $60 range.

And that's not allowing anything for assembly.   Soldering this stuff
together and testing it easily runs to an hour or two per unit for a
simple project.   One can pay for assembly, but that adds to the cash
outlay, and the units still need testing.

So the person doing the project is looking at putting in $3000+ up
front plus a huge amount of time and effort with no certainty that 100
of them will sell.  Even if one writes the time off as good-hobby-fun,
It make sense to try to get one's money back out of the first 50
units.

And now the price is up at about the same price as the expensive stuff
already on the market....

I'm not saying this is a good thing.  I'm just pointing out the
unfortunate economics of these kinds of projects.

If one can be reasonably certain of the demand, it's easier.   If the
volumes were larger, it would be much easier.

Jeff Walther

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