[Info-vax] Y3K for PDP-11 Operating Systems

[Johnny Billquist]

On 2011-05-04 06:01, Bill Gunshannon wrote:
> In article<H9mdnUTgT5LYfF3QnZ2dnUVZ_uOdnZ2d at giganews.com>,
> 	"Richard B. Gilbert"<rgilbert88 at comcast.net>  writes:
>> On 5/3/2011 8:07 PM, Bill Gunshannon wrote:
>>> In article<7d287cc3-4605-49a0-826e-fb92fc14e98d at j28g2000vbp.googlegroups.com>,
>>> 	onedbguru<onedbguru at yahoo.com>   writes:
>>>> On May 3, 2:39 pm, Henry Crun<m... at rechtman.com>   wrote:
>>>>> On 03/05/11 20:51, Bob Koehler wrote:
>>>>>
>>>>>>     >Bob Koehler wrote:
>>>>>
>>>>>>>> In article<bdd4fd3d-bb52-43fb-ad9c-746b901f4... at gu8g2000vbb.googlegroups.com>, jjh<jjhu... at gmail.com>     writes:
>>>>>
>>>>>>>> To make sure I understand, y3K =3D 3000, it is 2011 now...um that is 989
>>>>>>>> years from now...or roughly  12.5 lifetimes....I seriously don't think
>>>>>>>> that anyone in the year 3000 will want to know anything about DEC hw
>>>>>>>> or sw.
>>>>>
>>>>>>> You obviously have not read the historical documents.
>>>>>
>>>>>> I am curious, I have not read the historical documents.
>>>>>> Can you please post a link?
>>>>>
>>>>>> As for Y3K for RT-11, since the date is presently managed
>>>>>> up to 2099 as of V05.07 of RT-11, dates starting in 2100
>>>>>> become the next problem.  And since adding support only
>>>>>> for an additional 128 years seems like a complete waste of
>>>>>> time, then 3000 CE was chosen as the next minimum step.
>>>>>> In practice, at least an additional 4000 years would probably
>>>>>> be added, more than enough to handle dates until the rules
>>>>>> for the CE (Commercial Events, Common Era, Christian Era
>>>>>> or Gregorian - all are identical and have a 400 year cycle)
>>>>>> Calendar requires a rule change to handle years which are
>>>>>> less than the current 365.2418 days.
>>>>>
>>>>>> So Y3K is really just Y2.1K if that makes a difference.
>>>>>
>>>>> IIRC there was an article by someone from DEC who promised that RSTS would be
>>>>> patched to accept five-digit years before the year 9999. However I doubt that
>>>>> current versions would be supported until then...
>>>>>
>>>> question... who cares??? I can almost guarantee that none of us will
>>>> be here in 2099... and by that time you might be using neural-net
>>>> technology that will make the PDP look like a TRS80.
>>>
>>> Hey, just what xfdo you think was wrong with the TRS80?
>>>
>>
>> Other than primitive hardware and primitive software?  It was a good
>> machine in its day but its day is LONG GONE!
>>
>
> Now that's funny, here.  Just how is the Z80 more primitve than the PDP-11?
> And software?  At least 5 different OSes.  Wide language support.  Many
> commercial applications.
>
> And, at this point it is probably debatable which one between the TRS80
> and PDP-11 has more users on both real hardware and emulators.  I have
> quite a bit of both.

Actually, I know of plenty of PDP-11 systems still running critical 
applications in the industry. I have not seen a TRS-80 in the wild in 20 
years.

I'd it's not even a competition between these two machines. :-)

That said, the Z80 is more primitive in lots of ways. The instruction 
set is way more limited. You don't even have an MMU for the machine, and 
there is no way of doing a protected system where user applications 
can't do "bad" things, like turning off interrupts... There are a lot of 
things more primitive on the Z80. But I still use Z80 in products. It's 
a nice CPU for doing embedded things. So that architecture is still very 
much alive as well. Probably more alive than the PDP-11, since you can 
buy new Z80 cpus anywhere, but you'll have a very hard time finding a 
new PDP-11 anywhere, although you have commercial emulators for the latter.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol