Bakul Shah:
Being an OS student I had read "The Unix Timesharing System" paper by
Ritchie and Thompson and had wanted to use Unix years before I actually
had the chance. I don't remember an "Aha!" moment but I took to it like
a duck to water. Most everything felt just so comfortable and right.
It was very much as I had imagined it to be.
=====
That's more or less what it was like to me. Not so much
an aha! moment, more just a feeling of coming home. It
took a while to understand the different way things worked
in UNIX (I had previously used TOPS-10 for several years)
but as it all sank in it felt more and more right.
C felt the same way. It took me a while to grok the pointer
syntax (I had done a lot of MACRO-10 programming so I certainly
understood the concept, just not how it fit into the higher-
level language), but things like the three-clause condition
in for so that all control for a loop could be in one place
were just magically right.
I don't think I read the CACM paper before I touched UNIX,
but I had read both editions of Software Tools, so my brain
was perhaps pre-seeded with some of the ideas.
Norman Wilson
Toronto ON
> From: Warren Toomey <wkt(a)tuhs.org>
> But wasn't "chdir" built into the PDP-7 Unix shell?
No. See "The Evolution of the Unix Time-sharing System", in section "Process
control".
Also, the old 'cd' had different syntax than today's (since there was no notion
of a pathname in the earliest Unix); it took instead a list of directories (e.g.
"cd dd ken").
Noel
On 10/21/19 9:05 AM, tuhs-request(a)minnie.tuhs.org wrote:
> Message: 17
> Date: Mon, 21 Oct 2019 08:10:00 -0400 (EDT)
> From:jnc@mercury.lcs.mit.edu (Noel Chiappa)
> To:tuhs@minnie.tuhs.org
> Cc:jnc@mercury.lcs.mit.edu
> Subject: Re: [TUHS] What was your "Aha, Unix!" moment?
> Message-ID:<20191021121000.34E3B18C09F(a)mercury.lcs.mit.edu>
>
> > From: Warren Toomey<wkt(a)tuhs.org>
>
> > But wasn't "chdir" built into the PDP-7 Unix shell?
>
> No. See "The Evolution of the Unix Time-sharing System", in section "Process
> control".
>
> Also, the old 'cd' had different syntax than today's (since there was no notion
> of a pathname in the earliest Unix); it took instead a list of directories (e.g.
> "cd dd ken").
>
> Noel
>
Wanna have some fun?
chdir system
then try to find your way back 'home'...
v0's subdirectories suck.
--
GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF
On the copy of this story that appears here:
http://crash.com/fun/texts/vaxen-dont.html
it is atrributed as such:
'The author of this piece is Jack Harvey, harvey(at)eisner.decus.org, and
it was originally published under the title "The Immortal Murderer" on
January 18th, 1989 on DECUServe, the DECUS member bulletin board.'
--Pat.
In `UNIX Assembler Reference Manual,' Dennis credits Knuth
for numeric temporary labels, with a reference to volume 1
of The Art of Computer Programming.
I'm several thousand kilometers from my copy of Knuth (though
rather nearer to Knuth himself, albeit not within asking
range), so I'll leave it to others to track down the exact
reference.
Norman Wilson
Toronto ON
(temporarily Sacramento CA)
{Been meaning to get to this one for a while...}
> From: Pat Barron <patbarron(a)acm.org>
> The idea of processes being able to talk to each other (without some
> kind of pre-arrangement, like setting up a pipe between them, or using
> temporary files) was just amazing ... On V7m, I stumbled across the
> mpx(5) man page.
It's probably worth pointing out that before V7, stock Unix _didn't_ have a
way for two un-related processes to communicate, hence the invention of port()
by Rand. See:
https://minnie.tuhs.org//cgi-bin/utree.pl?file=BBN-V6https://minnie.tuhs.org//cgi-bin/utree.pl?file=BBN-V6/doc/ipc
(Note: BBN did _not_ do the original port() stuff, they just used it.)
Noel
A little off-topic, but quite amusing...
-- Dave
---------- Forwarded message ----------
Time to post this classic; I don't recall who wrote it. Note that the
references are pretty obscure now...
-----
VAXen, my children, just don't belong some places. In my business, I am
frequently called by small sites and startups having VAX problems. So when a
friend of mine in an Extremely Large Financial Institution (ELFI) called me one
day to ask for help, I was intrigued because this outfit is a really major VAX
user - they have several large herds of VAXen - and plenty of sharp VAXherds to
take care of them.
So I went to see what sort of an ELFI mess they had gotten into. It seems they
had shoved a small 750 with two RA60s running a single application, PC style,
into a data center with two IBM 3090s and just about all the rest of the disk
drives in the world. The computer room was so big it had three street
addresses. The operators had only IBM experience and, to quote my friend, they
were having "a little trouble adjusting to the VAX", were a bit hostile towards
it and probably needed some help with system management. Hmmm, hostility...
Sigh.
Well, I thought it was pretty ridiculous for an outfit with all that VAX muscle
elsewhere to isolate a dinky old 750 in their Big Blue Country, and said so
bluntly. But my friend patiently explained that although small, it was an
"extremely sensitive and confidential application." It seems that the 750 had
originally been properly clustered with the rest of a herd and in the care of
one of their best VAXherds. But the trouble started when the Chief User went
to visit his computer and its VAXherd.
He came away visibly disturbed and immediately complained to the ELFI's
Director of Data Processing that, "There are some very strange people in there
with the computers." Now since this user person was the Comptroller of this
Extremely Large Financial Institution, the 750 had been promptly hustled over
to the IBM data center which the Comptroller said, "was a more suitable place."
The people there wore shirts and ties and didn't wear head bands or cowboy
hats.
So my friend introduced me to the Comptroller, who turned out to be five feet
tall, 85 and a former gnome of Zurich. He had a young apprentice gnome who was
about 65. The two gnomes interviewed me in whispers for about an hour before
they decided my modes of dress and speech were suitable for managing their
system and I got the assignment.
There was some confusion, understandably, when I explained that I would
immediately establish a procedure for nightly backups. The senior gnome seemed
to think I was going to put the computer in reverse, but the apprentice's son
had an IBM PC and he quickly whispered that "backup" meant making a copy of a
program borrowed from a friend and why was I doing that? Sigh.
I was shortly introduced to the manager of the IBM data center, who greeted me
with joy and anything but hostility. And the operators really weren't hostile
- it just seemed that way. It's like the driver of a Mack 18 wheeler, with a
condo behind the cab, who was doing 75 when he ran over a moped doing its best
to get away at 45. He explained sadly, "I really warn't mad at mopeds but to
keep from runnin' over that'n, I'da had to slow down or change lanes!"
Now the only operation they had figured out how to do on the 750 was reboot it.
This was their universal cure for any and all problems. After all it works on a
PC, why not a VAX? Was there a difference? Sigh.
But I smiled and said, "No sweat, I'll train you. The first command you learn
is HELP" and proceeded to type it in on the console terminal. So the data
center manager, the shift supervisor and the eight day-operators watched the
LA100 buzz out the usual introductory text. When it finished they turned to me
with expectant faces and I said in an avuncular manner, "This is your most
important command!"
The shift supervisor stepped forward and studied the text for about a minute.
He then turned with a very puzzled expression on his face and asked, "What do
you use it for?" Sigh.
Well, I tried everything. I trained and I put the doc set on shelves by the
750 and I wrote a special 40 page doc set and then a four page doc set. I
designed all kinds of command files to make complex operations into simple
foreign commands and I taped a list of these simplified commands to the top of
the VAX. The most successful move was adding my home phone number.
The cheat sheets taped on the top of the CPU cabinet needed continual
maintenance, however. It seems the VAX was in the quietest part of the data
center, over behind the scratch tape racks. The operators ate lunch on the CPU
cabinet and the sheets quickly became coated with pizza drippings, etc.
But still the most used solution to hangups was a reboot and I gradually got
things organized so that during the day when the gnomes were using the system,
the operators didn't have to touch it. This smoothed things out a lot.
Meanwhile, the data center was getting new TV security cameras, a halon gas
fire extinguisher system and an immortal power source. The data center manager
apologized because the VAX had not been foreseen in the plan and so could not
be connected to immortal power. The VAX and I felt a little rejected but I
made sure that booting on power recovery was working right. At least it would
get going again quickly when power came back.
Anyway, as a consolation prize, the data center manager said he would have one
of the security cameras adjusted to cover the VAX. I thought to myself,
"Great, now we can have 24 hour video tapes of the operators eating Chinese
takeout on the CPU." I resolved to get a piece of plastic to cover the cheat
sheets.
One day, the apprentice gnome called to whisper that the senior was going to
give an extremely important demonstration. Now I must explain that what the
750 was really doing was holding our National Debt. The Reagan administration
had decided to privatize it and had quietly put it out for bid. My Extreme
Large Financial Institution had won the bid for it and was, as ELFIs are wont
to do, making an absolute bundle on the float.
On Monday the Comptroller was going to demonstrate to the board of directors
how he could move a trillion dollars from Switzerland to the Bahamas. The
apprentice whispered, "Would you please look in on our computer? I'm sure
everything will be fine, sir, but we will feel better if you are present. I'm
sure you understand?" I did.
Monday morning, I got there about five hours before the scheduled demo to check
things over. Everything was cool. I was chatting with the shift supervisor
and about to go upstairs to the Comptroller's office. Suddenly there was a
power failure.
The emergency lighting came on and the immortal power system took over the load
of the IBM 3090s. They continued smoothly, but of course the VAX, still on
city power, died. Everyone smiled and the dead 750 was no big deal because it
was 7 AM and gnomes don't work before 10 AM. I began worrying about whether I
could beg some immortal power from the data center manager in case this was a
long outage.
Immortal power in this system comes from storage batteries for the first five
minutes of an outage. Promptly at one minute into the outage we hear the gas
turbine powered generator in the sub-basement under us automatically start up
getting ready to take the load on the fifth minute. We all beam at each other.
At two minutes into the outage we hear the whine of the backup gas turbine
generator starting. The 3090s and all those disk drives are doing just fine.
Business as usual. The VAX is dead as a door nail but what the hell.
At precisely five minutes into the outage, just as the gas turbine is taking
the load, city power comes back on and the immortal power source commits
suicide. Actually it was a double murder and suicide because it took both
3090s with it.
So now the whole data center was dead, sort of. The fire alarm system had its
own battery backup and was still alive. The lead acid storage batteries of the
immortal power system had been discharging at a furious rate keeping all those
big blue boxes running and there was a significant amount of sulfuric acid
vapor. Nothing actually caught fire but the smoke detectors were convinced it
had.
The fire alarm klaxon went off and the siren warning of imminent halon gas
release was screaming. We started to panic but the data center manager shouted
over the din, "Don't worry, the halon system failed its acceptance test last
week. It's disabled and nothing will happen."
He was half right, the primary halon system indeed failed to discharge. But the
secondary halon system observed that the primary had conked and instantly did
its duty, which was to deal with Dire Disasters. It had twice the capacity and
six times the discharge rate.
Now the ear splitting gas discharge under the raised floor was so massive and
fast, it blew about half of the floor tiles up out of their framework. It came
up through the floor into a communications rack and blew the cover panels off,
decking an operator. Looking out across that vast computer room, we could see
the air shimmering as the halon mixed with it.
We stampeded for exits to the dying whine of 175 IBM disks. As I was escaping
I glanced back at the VAX, on city power, and noticed the usual flickering of
the unit select light on its system disk indicating it was happily rebooting.
Twelve firemen with air tanks and axes invaded. There were frantic phone calls
to the local IBM Field Service office because both the live and backup 3090s
were down. About twenty minutes later, seventeen IBM CEs arrived with dozens
of boxes and, so help me, a barrel. It seems they knew what to expect when an
immortal power source commits murder.
In the midst of absolute pandemonium, I crept off to the gnome office and
logged on. After extensive checking it was clear that everything was just fine
with the VAX and I began to calm down. I called the data center manager's
office to tell him the good news. His secretary answered with, "He isn't
expected to be available for some time. May I take a message?" I left a
slightly smug note to the effect that, unlike some other computers, the VAX was
intact and functioning normally.
Several hours later, the gnome was whispering his way into a demonstration of
how to flick a trillion dollars from country 2 to country 5. He was just
coming to the tricky part, where the money had been withdrawn from Switzerland
but not yet deposited in the Bahamas. He was proceeding very slowly and the
directors were spellbound. I decided I had better check up on the data center.
Most of the floor tiles were back in place. IBM had resurrected one of the
3090s and was running tests. What looked like a bucket brigade was working on
the other one. The communication rack was still naked and a fireman was
standing guard over the immortal power corpse. Life was returning to normal,
but the Big Blue Country crew was still pretty shaky.
Smiling proudly, I headed back toward the triumphant VAX behind the tape racks
where one of the operators was eating a plump jelly bun on the 750 CPU. He saw
me coming, turned pale and screamed to the shift supervisor, "Oh my God, we
forgot about the VAX!" Then, before I could open my mouth, he rebooted it. It
was Monday, 19-Oct-1987. VAXen, my children, just don't belong some places.
-- Dave
where did the relative labels come from? I still show them to people
when we're doing assembly and still use them all the time. Most people
have not seen them and find them wonderfully convenient. I know they
were in as by the time I came along in 1976; when did they first show
up?
I'm amused (in a good way) that this thread persists, and
without becoming boring.
Speaking as someone who was Ken's sysadmin for six years,
I find it hard to get upset over someone cracking a password
hash that has been out in the open for decades, using an
algorithm that became pragmatically unsafe slightly fewer
decades ago. It really shouldn't be in use anywhere any
more anyway. Were I still Ken's sysadmin I'd have leaned
on him to change it long ago.
So far as I know, my password from that era didn't escape
the Labs, but nevertheless I abandoned it long ago--when
I left the Labs myself, in fact.
I do have one password that has been unchanged since the
mid-1990s and is stored in heritage hash on a few computers
that don't even have /etc/shadow, but those are not public
systems. And it's probably time I changed it anyway.
None of this is to excuse the creeps who steal passwords
these days, nor to promote complacency. At the place I now
work we had a possible /etc/shadow exposure some years back,
and we reacted by pushing everyone to change their passwords
and also by taking various measures to keep even the hashes
better-hidden. But there is, or should be, a difference
between a password that is still in use and one that was exposed
so long ago, and in what is now so trivial an algorithm, that
it is no more than a puzzle for fans of the old-fart days.
Norman Wilson
Toronto ON
Apropos of OCR on shabby typewriting, I've had good luck with doing
the OCR twice with the paper differently positioned, then using diff
to spot discrepancies. For a final proofreading, a team of two--one
reading the original aloud, the other checking the copy, works much
faster and more accurately than a single person checking side-by-side
texts.
Doug
