[rescue] huge DEC rescue in TX?
waisun.chia at hp.com
Thu Feb 3 06:01:16 CST 2005
Jonathan C. Patschke wrote:
> On Wed, 2 Feb 2005, Wai-Sun Chia wrote:
>> PDPs doesn't even have socket arrays!
> That's funny. There are quite a lot of socketed chips on mine.
I was refering to the CPU: i.e. there's no socketed CPUs like the PGA
(socket 7), etc.
>> That's why they last so long! The Unibus PDPs have all discrete TTL
>> CPUs; i.e. the CPU is implemented in multiple boards.
> That is, indeed the case. The point I was making was that the craziest
> they got with connecting things together was the occasional socket here
> and there. Most everything else is soldered or, in the case of the
> backplane, wire-wrapped together.
Yeah. The wierd thing is that even though a wire-wrapped backplane
*LOOKS* flimsy, it is quite robust indeed. The fact that they're still
working after 25-30 years is a testament of the engineering quality that
goes into a typical PDP.
> I think the "CPU" is just a single 40-pin DIP. The others are the MMU
> and additional microcoded instructions. Everything about that platform
Well, to me a MMU and microcode are *part* of the CPU. :-)
If DEC had the technology then, they would've just crammed everything
into a single 40-pin DIP (just like the i386 and i387).
> is an amazing study in efficiency and conservative engineering.
>  Well, aside from the 11/70. There's -nothing- conservative about
> that beast.
Well, try a KL10! This uses 12.6kW (3ph at 35A/ph/120V) just for the
processor; no core, no disks, no peripherals!!
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