OT: A call to arms (sort of)

From: Philip.Belben_at_pgen.com <(Philip.Belben_at_pgen.com)>
Date: Wed Jul 7 07:50:23 1999

>>And as I invented the term in this thread I get to confirm that Tony is
>>using the correct definition :-) "Open Hardware" is hardware that is
>>documented well enough such that anyone can recreate it from the
>>documentation. This includes VHDL specs, PAL equations, etc.
> Are you guys familiar with the "Open Hardware Certification Program" (I
> haven't heard it mentioned)?
> They've got a list of their own requirements at
> <http://www.openhardware.org/conditions.html>

Thanks, Tom, very interesting URL. I wasn't familiar with it, but it is quite
close to my view of "open hardware". I would tend to extend this so that not
only are devices supplied with enough info to write drivers, but they are also
supplied with enough info to connect them to computers using other buses. In
many cases this is the same, but it would help to have a definitive list of
(say) what features of the bus they need / don't like / can take advantage of.

To return to Chuck and Tony's definition, yes, very laudable. But I don't think
you should _impose_ the requirement that everyone who builds hardware for the
open system should make everything public. And I like Dick's idea of taking an
existing standard, in the same way that Linux (for example) took the UNIX
system, so that there is already a wide range of stuff available for your
system. And users can build as open or closed a system as they like.

Dick, I'm not sure what you meant by buying stuff "that does what you want but
doesn't conform to some standard" - that seems to be the opposite way round to
our discussion, which was about defining an open bus, and whether kit you buy
(which _does_ conform to the standard) will work with the bus we've defined, or
whether the differences between our open definition and the standard will
prevent it.

ISA is a standard - of sorts. You can adopt it, and reap the benefit of the
standard, because a lot of kit will work with your system. Or you can reject
it, and said kit won't work with your system. You seemed to be suggesting the
adoption of a partial ISA standard. And some ISA kit will work with it, and
some won't. Fine for true open hardware, since you can tell what will and won't
before you buy it. But difficult to use the existing ISA kit with your open
bus, since it is the existing ISA kit that is not open, so you can't easily tell
whether the ISA card you had in mind will work on the modified bus. So why
bother with ISA at all?

On this point I agree with Tony. Edge connectors in slots, while fine for the
volume market, doesn't help the homebrew hobbyist. So if we choose an existing
bus on which to base our new open bus, choose one with indirect connectors, like
VME. True, few hobbyists will homebrew _everything_, but by the Chuck/Tony
definition of open, they should be able to, if they wish.

A system aimed at homebrew also makes it easier for designers to publish designs
which other people then build. Kits can be made of standard parts and not
require custom PCBs. And when the bugs have been ironed out, then the PCB
design can go off to the mass production plant...

Received on Wed Jul 07 1999 - 07:50:23 BST

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