70's computers

[allison]

On 10/24/2018 09:19 AM, Paul Koning via cctalk wrote:
>
>> On Oct 23, 2018, at 7:08 PM, Noel Chiappa via cctalk <cctalk at classiccmp.org> wrote:
>>
>> ...
>> There was a recent discussion about code density (I forget whether here, or
>> on TUHS), and someone mentioned this paper:
>>
>>  http://web.eece.maine.edu/~vweaver/papers/iccd09/iccd09_density.pdf
>>
>> which shows that for a combo of benchmarks, the PDP-11 had the densest code
>> out of all the ones they looked at. (They didn't look at the PDP-8, but I
>> suspect that since it's a single-address design, it's almost ceertainly not
>> as dense.)
>>
>> The PDP-11 dates back to the days of core (it went through several generations
>> before DRAM arrived - e.g. the -11/70 originally shipped with core), and given
>> core prices, minimizing code size was pretty important - hence the results
>> above.
> What's interesting is that the paper uses compiled code.  The gcc back end for pdp11 is still a work in progress and clearly doesn't deliver best possible code, certainly not back then.
>
> 	paul
>
I found that paper to be a not so interesting and more or less
pointless.  For many applications its what's on the
chip and rarely does it focus on architecture.  Engineers need to do
things or produce things that work
and  most of the time it comes down to whats available and price.  With
embedded machines the IO
capability and resident memory are likely deciding factors more so than
if its Harvard or Von, RISC
or CISC.   The other is the tool chain costs in, acquisition cost,  time
to learn, and apply.

Allison