[Oberon] Re (2): Updated RiskFive FOM schematics

peter at easthope.ca peter at easthope.ca
Tue Jan 16 19:08:25 CET 2018

From:	Paul Reed <paulreed at paddedcell.com>
Date:	Tue, 16 Jan 2018 16:42:21 +0000
> I both agree and disagree with you. :)
> ... 
> Maybe the way forward is to use SMD, but design
> for hand-re-workability wherever possible.
> Just my two .5mm-spaced pins :)

Interesting.  Thanks for the ideas and explanations.

From:	"Skulski, Wojciech" <skulski at pas.rochester.edu>
Date:	Tue, 16 Jan 2018 16:48:08 +0000
> Use a reputable manufacturer with proven track record. Manufacturers 
> are not equal. Some do lousy work, some do excellent work. A well 
> assembled board is very reliable. 

Accepted fully.  A customer or user must accept that quality costs 
more and expenditure on quality is a good investment; not a squandering.
The OLPC XO and Pyra is are nice examples.  

> Less critical boards, like RiskFive, do not provide such extensive 
> monitoring features. However, you can monitor internal FPGA voltages 
> and the temperature, using its built-in ADC. The appropriate software 
> needs be written, of course.

Thousands of hours are invested in hardware, firmware and software to 
make a system work.  What evolves in the subsequent decade?   Will 
hardware remain available?  How much effort will be necessary to adapt 
firmware and software to changes in hardware?

Incidentally, most of us are old-timers.  I hope Oberon is still viable 
fifty years from now.  Alternatives are becoming worse rather than 

> This conclusion seems logical, but it is wrong. Sockets do not provide 
> the bandwidth which is required by modern interfaces. A standard ball 
> grid array (BGA) pin can operate at over 1 gigabit per second per pin. 
> Special mutligigabit transceiver pins (MGT, which I am not using on 
> RiskFive) can operate at gigabits per second, as the name suggests. A 
> socket pin can provide a couple hundred megabits per second at the 
> best.

 I understand that speed is a critical factor for data acquisition and 
for intensive computation.  Conversely, System 3 on a 486 PC was a 
useable workstation.  For genuine requirements of a workstation, 
Pentiums became overkill.  If RiskFive is far more powerful than I 
need but has a mean time to failure of five years and a compatible 
replacement will not be available in five years, is it a good basis 
for a workstation?

Questions are inescapable.  Not intended to be critical or offensive.

Best Regards,                    ... Peter E.

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