FPGA VAX update

[Holger Veit]

woodelf wrote:

> Bjørn Vermo wrote:
>
>>
>> Apple comes to mind. You can pick up a G4 really cheap these days. 
>> Whether you want to run BSD (OS X) or Linux is a matter of taste.
>> IBM have some PPc development systems (Walnut if I recall right) 
>> which can run both Linux and QNX, but I have no idea how to get one 
>> or what they sell for.
>
>
> I guess nobody even considers building a computer from scratch. :(
>
About thirty years ago, when I was pretty much younger :-), I built a 
classical TTL computer (with 74181 ALUs etc.) almost from scratch, 
basically from schematic fragments from the TTL databook and TTL 
cookbook and some electronics magazines; well - if it were really from 
scratch, then even so "highly integrated chips" like the 74181 were 
prohibited as well. Looking back, this had almost all characteristics of 
a real computer.

There are two aspects IMHO why this does no longer happen today:
- what was a known magazine in the past, would today perhaps 
realistically called "Un-Popular Electronics", the knowledge of 
electronics from the ground up is dying out; and with the continuing 
"digitalization" of technology, it is an ever increasing hurdle to get 
started - the classical AM detector radio I built as a newbie will 
nowadays no longer attract anyone - you can get a gadget which is better 
by several magnitudes for a fraction of the expenses you'd have for 
soldering your thing.
- The tools you have are too user friendly (!); i.e. you could rather 
easily click something together, be it software or VHDL code for an FPGA 
without ever needing to understand what is really going on. The "soul of 
a new machine" guys that traced glitches with a logic analyzer in a 
large wire-wrapped TTL graveyard are gone - such a machine had the 
necessary wow factor. No surprise when a VAX in an FPGA - see subject - 
is not really interesting. It is possible - that's it. But what does one 
gain? It is like solving a 10000 pieces puzzle; spend time and don't 
learn really much.
When Hillary climbed the Mount Everest 50 years ago, it was something 
new, extraordinary. When tourist nowadays use sort of stairways to reach 
the top (okay, it's not *that* extreme now), it is just uninteresting. 
But standing on the top, is still a challenge and an experience for the 
individual. However, what we lost now is a sense of wonder - that small 
ALU based TTL circuit was built by myself, and I did it, and it is 
irrelevant that some idiot could download a digital simulator and click 
the same circuit together on a PC screen. I guess this is what makes the 
difference between a real PDP-11 with some ridiculous 5MB storage disks 
compared to a SIMH emulator running on a 3GHz Pentium.
Watch the blinkenlights.

Holger