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

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.


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