What's the rarest or most unusual computer-related item do you own? [Tek 4132]
rickb at bensene.com
Sat Jan 14 21:10:55 CST 2017
I initially wrote in response to this thread:
>>>> - A Tektronix 4132 Unix workstation using a National 32016 CPU and
>>>> a 4.2bsd port called UTek
>> Jon responded:
>>> Gee, how does it perform? I built a clone of a Logical Microcomputer Co. 32016 Multibus system and got it working.
>>> But, it was glacially slow! I did have some memory that was likely a little slower than the stock memory, but it wasn't insanely slow. But, firing up certain >>>things like editors was just maddening. And, I'm not talking about Emacs, just vi. I eventually got a MicroVAX-II to replace it, and, yes, that DID have a cache
>>>to speed up the memory, but it was quite a difference.
..and I responded with:
>> Well...considering the era, it wasn't too bad. By today's standards, yeah, it's pretty darned slow.
>> Vi starts up pretty quick, even with a couple of terminals running on it. It runs rogue pretty nicely, quick enough for multiple people to play it at once.
>> The machine has 7MB of RAM, which really helps. Without additional RAM, there's only 1MB on the main board, and running it with just 1MB makes it >>incredibly slow. There isn't any external cache.
And Jon wrote back:
>Ahh, that may be part of the difference. I can't remember how much memory I had on it. I would not be surprised if it was as tiny as 128 KB, or maybe 256 KB. >I'll check my schematics to see how many address lines were implemented.''
With that little memory, even with cache, it was bound to be slow, and probably ended up paging a lot.
> If mine hadn't performed so poorly, I might have continued to use it, and upgraded parts.
> I got versions of Genix and Xenix with it. These were likely early ports for the 32016, and may have had poor implementations for the MMU for instance.
The real difference was likely that UTek was a pretty true port of Berkeley 4.2 for the VAX, which was a really good fit for the mature (for the time) virtual memory management features offered by BSD Unix, and the demand-paged virtual memory capabilities of the 32016 chipset.
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