Xah Lee's Unixism

jmfbahciv at aol.com jmfbahciv at aol.com
Thu Sep 9 15:21:45 CEST 2004

In article <5sjnhc.bb81.ln at via.reistad.priv.no>,
   Morten Reistad <firstname at lastname.pr1v.n0> wrote:
>In article <413f049f$0$6914$61fed72c at news.rcn.com>,  <jmfbahciv at aol.com> 
>>In article <p9qdnTnxTYDJR6PcRVn-pw at speakeasy.net>,
>>   rpw3 at rpw3.org (Rob Warnock) wrote:
>>>John Thingstad <john.thingstad at chello.no> wrote:
>>>| As you may know XP is not particularly good as a server.
>>>| I would go for some Unix implementation (perhaps free-BSD)
>>>| As a workstation XP seems OK.
>>>| I hear a lot of complaints about XP's stability.
>>>| Since I have not administered a XP network, yet, I cant comment on 
>>>| But in my personal experience it is a stable system.
>>>| I frequently let my computer run 24 hrs. a day for more than a month  
>>>| without a need to reboot. So for me it is adequate.
>>>*Only* a month?!?  Here's the uptime for one of my FreeBSD boxes
>>>[an old, slow '486]:
>>>    %  uptime
>>>     2:44AM  up 630 days, 21:14, 1 user, load averages: 0.06, 0.02, 0.00
>>>    % 
>>>That's over *20* months!!
>>I bet we can measure the youngster's age by the uptimes he boasts.
>>>p.s. I remember the time back in the early 70's (at Emory Univ.) when
>>>we called DEC Field Service to complain that our PDP-10 had an uptime
>>>of over a year. Why were we complaining? Well, that meant that DEC Field
>>>Service had failed to perform scheduled preventive maintenance (which
>>>usually involved at least one power cycle)...  ;-}
>>One?  Had to be two.  FS was supposed to use their service pack
>>as the system disk, not the customers!!!  I believe that was
>>true even in 1970.  The dangers of smushing bits was too great.
>But with a PM you had to do a cold start. All the disks had to be 
>spun down, filters changed, and they had to spin for an ungodly long
>time after the filter change before heads could be enabled again. This
>was to bring all the dust that was let loose in the process into the new
>filters before heads went to fly over the platters again.

That's why there was always two boots; one for FS to bring up thier
service pack to run diags; the other one was when the system was
handed back to the customer.

>Also power supplies had to be checked for the dreaded capacitor
>problems. Tape drives also had these. This was industry-wide 
>problems; and news from a few burned UPS'es the last couple of
>months tell me that the capacitor problems are still with us.
>It was a real accomplishment when we in 1988 could do a full
>PM (Prime gear) without shutting down the system. All disks were
>mirrored, and all power duplicated, so we shut down half of the
>hardware and did PM on that; and took the other half next week.

That's exactly what JMF's and TW's implementation of SMP gave
the customer.  Not only that but a catastrophic hardware failure
no longer brought down the whole system.  What was really amusing
to me is that TW and JMF had no idea what they'ld created.  The
first time I told them that a system would never ever have
to be rebooted, I grew two heads.  OTOH, it was impossible
to convince FS that a PM didn't have to be a system-wide PM.

I don't think we ever got that change permutated throughout the
>SMD filters were used at a quite high rate; even inside well 
>filtered rooms. ISTR 6 months was a pretty long interval between PM's. 

Our FS liked to have PMs done weekly and then a major PM done monthly.
I never had time to learn exactly what the procedures were.  They
were documented and laid out but I don't know what happened to
that info.


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