FPGA VAX update

Allison ajp166 at bellatlantic.net
Sun Oct 23 16:54:49 CDT 2005


>
>Subject: Re: FPGA VAX update
>   From: woodelf <bfranchuk at jetnet.ab.ca>
>   Date: Sun, 23 Oct 2005 14:58:39 -0600
>     To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Chuck Guzis wrote:
>
>>Slightly OT:  How fast (in comparison to the original 11/780) do PC-based
>>emulators run?  My only close-up exposure with this line was a couple of
>>years with an 11/750.  It didn't seem like a speed demon then.
>>

The 750 was around .6 to .7 a 780 for the cpu however the mass storage 
systems for the 780s were more elaborate and faster. 

>The emulators run alot faster, but the problem is the 11 is still a 
>commerical product
>so I don't think we will get better new hardware out.
>
>>If PC-based emulators are fast enough, why bother with the IC version?  An
>>intellectual exercise?  Or will the FPGA version run an order of magnitude
>>faster than the original?
>>  
>>
>I suspect about the same speed  as PC's 15 years ago or 74Sxx speeds.  
>The real speed limit on computers
>now days is the cache memory.  A external bus depending on memory used  
>is the factor.
>Most common memory is  about 120 ns to 70 ns access time unless you want 
>to use the latest
>chips.

70ns was 1982 tech level.  Tech for 1995 was 25ns for memory.  
Current is under 1ns.  

Don't forget one of the features of current hardware is the 1ns/ft
barrier is outside the chip.


Allison



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