Tuesday, August 02, 2005

Three Things

Thing 1, Why do people think it is OK to update the data dictionary? Thing 2, remember punch cards, I found an article that will put them in perspective. Thing 3, are you ready to get a headache staring at some optical illusions?

First, I’ve written about this before but it keeps happening.  Why why WHY do people feel obliged to update the data dictionary.  That has to be the most reckless thing I can think of anyone doing or suggesting – unless it was support (and they had development ‘bless’ it).  It happened again today – someone asked how to update the ALL_DIRECTORIES view (it wouldn’t update, thankfully).  Why?  They wanted to change the path a directory pointed to.  I was very thankful the view wasn’t updatable – explained that DDL is the only way to modify the dictionary.  Said “don’t go there”.  Unfortunately, they figured out DIR$ is the table underlying the view and updated it. Sigh. I cannot understand why this happens.  It is the reason asktom got started, someone suggesting a dictionary update.  I will never understand the mindset that thinks it would be OK to do this.

On a lighter note, remember punch cards?  In high school, we loaded up the card punch, punched our code into it (Cobol and RPG) and mailed them downtown to be compiled (not making that up, mailed them downtown).  We would get the compiled listings back the next week.  You made darn sure things were going to be as perfect as possible.  It made you program differently, that is for sure – no typing in and seeing what sticks. You wanted it perfect the first time around.  Well, today someone related an MP3 in terms of punch cards.  They calculated how tall the stack of punch cards would need to be to hold a 3 minute MP3.  Turns out that I would be able to hide behind the stack (if it were wide enough, it would be just tall enough).

Lastly, I stumbled upon these three very cool optical illusions.  I agree with the comment on that site that illusion 3 is the most incredible.  Very cool, you cannot believe what your eyes see all of the time.  Seeing is not always believing!

Oh, I’ll add a fourth thing, just downloaded RH 4.0 and will be giving that a go.  Doing a trial install in vmware right now and if I like what I see, I’ll be rebuilding my server with it tonight.  I got the kernel, I got it compiled, but I ran out of time trying to boot with it last night.  Thought it might be easier just to go to version 4.0



Blogger Niall said....

Well you know some os's positively encourage you to hack the os kernel, which is kinda equivalent - so I guess we'll see more of this and not less :(

Tue Aug 02, 05:05:00 PM EDT  

Blogger Robert Vollman said....

Wow, I liked those optical illusions, especially the first and last. Neat!

Tue Aug 02, 06:10:00 PM EDT  

Blogger Thomas Kyte said....

I liked those optical illusions,

My daughter Megan doesn't quite believe them, she is sure they are a computer trick :)

Tue Aug 02, 06:59:00 PM EDT  

Anonymous Anonymous said....

I am curious why people feel the need to re-create the wheel. For instance, we all know the databsase already has the ability to store comments on the column level. However, the folks I am working with right now decided to create a new "data dictionary" table that stores table name, column name, data type and description. So now, when we change a table, we have to go in and update this table with the new data.

While this is no where near as dangerous as updating the data dictionary, it seems about as smart.

Tue Aug 02, 08:55:00 PM EDT  

Anonymous Eddie Awad said....

My daughter Megan doesn't quite believe them, she is sure they are a computer trick

I agree with your daughter. Do you have a proof that they are NOT a "computer trick"? Note, however, that I do not have a proof that they are a computer trick either.

In any case, they're neat. Thanks for sharing.

Tue Aug 02, 09:13:00 PM EDT  

Blogger Connor McDonald said....

WHY do people feel obliged to update the data dictionary

Gee, um, err, maybe it could be...

$ oerr ora 28606
28606, 00000, "block too fragmented to build bitmap index (%s,%s)"
// *Cause: The block(s) exceed the maximum number of rows expected when
// creating a bitmap index. This is probably
// due to maximum slot allowed set too low.
// The values in the message are:
// (slot number found, maximum slot allowed)
// *Action: alter system flush shared_pool; update tab$ set spare1 = 8192
// where obj# = (select obj# from obj$ where NAME=table_name AND
// owner# = table_owner; commit;


Tue Aug 02, 09:25:00 PM EDT  

Blogger Joel Garry said....

1. Because some fishy guy said it was a rule? (Rule 4: Dynamic On-Line Catalog Based on the Relational Model)

2. I still have COBOL stacks from 25 years ago. Operator trainees would walk across Wilshire Blvd with boxes of cards on a furniture mover. We quickly learned to put a stripe diagonally on the side of the deck, no sorter allowed. For Fortran in high school (using the school districts IBM 360) we would fill out forms for the keypunch operators. One guy figured out JCL to dump lots of stuff. He owns a telephone company now. He and his ol' lady ride Harleys.

3. Not after eating.

Tue Aug 02, 11:16:00 PM EDT  

Anonymous Anonymous said....

" Do you have a proof that they [the illusions] are NOT a "computer trick"? "

Should be simple enough to test if you have a decent colour printer.
Even if not, you would be able to do a screen snapshot of the illusions and a photo editing package will have some gadget for getting the RGB values at a point.

Wed Aug 03, 02:56:00 AM EDT  

Anonymous Flado said....

< quote>
It is the reason asktom got started, someone suggesting a dictionary update.
< /quote>

Well, if it was the sole reason we now have such a wonderful resource, it deserves a memorial :-)

Wed Aug 03, 05:10:00 AM EDT  

Anonymous Anonymous said....

Optical illusions....

I was skeptical also! :)
I used paper to cover everything up and yes they are the same color! Amazing!


Wed Aug 03, 08:07:00 AM EDT  

Anonymous Scott Mattes said....

What is RH?

Wed Aug 03, 08:09:00 AM EDT  

Anonymous Anonymous said....

This site was refered by Neal Gafter (JAVA compiler Team - Former member and Currently with Google ) for optical illusions


Wed Aug 03, 08:11:00 AM EDT  

Anonymous Anonymous said....


This site for optical illusions for refered by Neal Gafter of Google (former JAVA compiler team member).

Wed Aug 03, 08:21:00 AM EDT  

Blogger Thomas Kyte said....

what is RH

sorry about that, RH is RedHat

Wed Aug 03, 08:30:00 AM EDT  

Anonymous Anonymous said....

Wish I still had some of those logo punch cards (school, organization, or corporate logo watermarked on the card) from the 1970s. They were ubiqitous trash in the 1970s; would be very cool to have a collection of them now.


Wed Aug 03, 10:10:00 AM EDT  

Blogger DaPi said....

Cards! A couple of grandpa's war stories:

I slaved for weeeks over pages of 360/assembler. For fun I wanted to see the assembler output (link module?) on cards. All my work fitted on FIVE cards, two of which said begin and end.

Importance of data compression on cards (e.g. MP3):
a) fewer cards, so they weigh less
b) more holes, so they weigh less

Wed Aug 03, 12:46:00 PM EDT  

Anonymous John spencer said....


When I was in high school, cards would have been the height of luxury. We had a teletype machine and paper tape. You typed your program on the teletype and it produced a long slip of paper tape about .75 inches wide. You then stuffed the handset of the attached phone in a rubber docking cradle on the 300 baud modem fed in your tape, dialled the computer centre number on the rotary dial phone and punched send. God help you if you put the tape in upside down.

Wed Aug 03, 01:26:00 PM EDT  

Anonymous Anonymous said....

John Spencer:

How would punch cards be easier than the receipt tape you described. The receipt tape could be input in one of two ways, but if you happened to drop or misorder a few (or all) the cards, you might've had to redo the whole program!

Wed Aug 03, 02:23:00 PM EDT  

Blogger Howard J. Rogers said....

I remember that in about 1977, one of our classes was the victim... er, I mean the guinea-pig... for a 'computerisation of tests' process. The multi-choice test consisted of marking up punched cards, which were to be sent off to some data processing centre for "marking". Suffice it to say, 28 years later, I still have no idea how I did on that test: the results never came back, and it was something of a joke for about a year afterwards!

I have often wondered how big my roll of punched tape would have to be if it was to record merely one of my FLAC tracks!

Regarding the data dictionary: if Oracle would stop telling people to delete from AUD$ to clear the audit trail, that would help.

And regarding the optical illusions: I'd love to see them, but Firefox reports that a plugin is needed. Any idea which one? Because Firefox has a hunt around for a likely suspect, and ends up reporting that an "unknown" plugin is needed. Very frustrating.

Wed Aug 03, 03:28:00 PM EDT  

Blogger Thomas Kyte said....

The only plugin I have is flash, it was flash based....

Wed Aug 03, 03:39:00 PM EDT  

Blogger Alberto Dell'Era said....

The "checks-and-cylinder" visual illusion is scientifically explained (by the author of the illusion himself!) here, for those who wonder ;)

Wed Aug 03, 04:32:00 PM EDT  

Blogger Howard J. Rogers said....

Oh well, I gave up and used Internet Explorer... No flash plugin is available for 64-bit Fedora Core 4, apparently. The perils of the bleeding edge!

Anyway: the Gimp's eyedropper reports that the first illusion does indeed show two identical colours on the different squares, and I find myself still saying, "It can't be!"... I like that one very much.

But the third one... no matter where I sample the colour from on that middle piece (bits of it are in shadow after all), I always get different hexadecimal values for the colour, so saying they are "identical" is a bit of stretch.

But the values are a good deal closer (basically, shades of tinted grey) than the colours look, so it's still good value as an illusion goes, I guess.

Thanks for the fun, Tom!

Wed Aug 03, 05:00:00 PM EDT  

Anonymous John Spencer said....

At least with punch cards, you could mark the card for physical order, Joel's stripe on the side of the deck works. The card punch machine I used in university actually added a number on a corner of the card to indicate proper order.

The paper tape came off a big roll in the machine and really liked to curl back up. Sometimes it would curl up when feeding into the machine, catch on the mechanism and tear. Scotch tape was not an option.

Wed Aug 03, 05:06:00 PM EDT  

Anonymous Quadro said....

I think they changing the color of this funky SWATCH box while you moving it around.

Wed Aug 03, 06:44:00 PM EDT  

Anonymous Michael Olin said....

As I remember it, the paper tape had a series of holes running down the middle of it, off center, that engaged the sprocket that moved the tape along. You couldn't feed the tape in upside down, the sprocket holes would not line up.

Somewhere, I have the Fortran source for the Crystal Cave Adventure game on paper tape. It is a roll about six inches in diameter.

In High School we had one of those 10-cps teletypes connected to a PDP-10 running RSTS/E. We quickly figured out that if you opened a new file for output in BASIC and specified a large file size, you ended up with a core dump in the file. It took about a week until we had the source code for the login program...


Wed Aug 03, 09:56:00 PM EDT  

Anonymous Anonymous said....

Somewhere in the mess that is a basement I have a box of unused punch cards. I think the 'real name' was Hollorith coding cards.. Too lazy to look it up.
If I remember they had 12 slots to punch vertically.

Wed Aug 03, 10:56:00 PM EDT  

Blogger Joel Garry said....

a PDP-10 running RSTS/E

Not likely. The PDP-10 was a 36 bit system, RSTS/E was for the 16 bit PDP-11. Although there were emulators that ran on the 10, it is unlikely your school used that. Getting the login source is some good hackin', though.

Sorry for the picking of nits, but to some of us that is like saying Rdb is Oracle. You could get away with it in some places...

IIRC, you could do the paper type upside down and backwards, they didn't always wind up on a reel :-O

Thu Aug 04, 12:00:00 AM EDT  

Anonymous adewri said....

Wow, that was unbelievable. Even after using the masks I was doubtful. At first I though I need an eye checkup. I ended up showing it to every one here at work to make sure I’m not the only one who sees it the way I see :).

And out of context I wanted to ask you some thing. What is your approach to something new? How do you dig it? For example 10g Release2 is out now and has some new features. It’s available for every one to try it out. I did try out some examples from the manuals but the way you show the examples makes me say every time "Hey, why didn’t I think of it before ?" ,"Wow, never thought it could be done this way also." And the explaination is like "No one can explain it better", clear and to the point. I wanted to know what your thought process is, that triggers such wonderful examples and explanations.

Thu Aug 04, 12:26:00 AM EDT  

Blogger rjanson said....

Tom, you mention that you 'downloaded' RH 4. Is there a free version of this available? I was under the impression that only Fedora was freely available. Of course, it's entirely possible that Oracle and RedHat have a partnership going making it free for you to download...

Thu Aug 04, 12:44:00 AM EDT  

Blogger Noons said....

Re those optical illusions:

Tom, I reckon the third one or
the first one are the perfect cover for your new book! If there are no copyright issues, of course.

Perfect application: clear up myths, make people see clear, that sort of thing.

Thu Aug 04, 04:24:00 AM EDT  

Blogger DaPi said....

"IIRC, you could do the paper type upside down and backwards"

This was essential. The PDP7 assembler punched the code first and the symbol table at the end. The loader needed the symbol table first.

Thu Aug 04, 05:30:00 AM EDT  

Blogger Thomas Kyte said....

you mention that you 'downloaded' RH 4

Yeah, I bought it and downloaded it. Oracle and Redhat do have a relationship, but this is for my equipment.

You can download the ISO's for 30 day trials anytime you want from redhat

Thu Aug 04, 07:05:00 AM EDT  

Blogger Bill S. said....

DaPi's grandpa war stories brought back memories for me, but I have one for the rest of you geezers to laugh at - in high school, my Intro to Computers class used an old dinosaur of a machine (was an IBM, can't recall the model) that we programmed using wiring boards. Certainly was an eye-opener when I advanced into the "real world" and got to use punch cards. :-D

Thu Aug 04, 09:57:00 AM EDT  

Anonymous Michael Olin said....

I'm sure you're right Joel, it must have been a PDP-11.

Getting the login source wasn't good hacking, it was just dumb luck (although perhaps that's a significant piece of good hacking...).

As far as putting the paper tape on a spool, I never did that. We started winding it around a pencil when it was being punched (and if I remember correctly, wound it backwards around another pencil to get the start of the tape on the outside of the roll) then removed the pencil(s) and had something that vaguely resembled a very thick coaster. I suppose you could have run the tape through upside down and backwards to get around the off-center sprocket holes. It was always obvious on our tapes which side was up, thanks to the tight coil around the pencil.

Eventually the school brought in some high-tech personal computers, Commodore PETs with built in cassette drives for storage.


Fri Aug 05, 01:41:00 PM EDT  

Anonymous Anonymous said....

I didn't believe the illusions, either. So, I copied the pictures into Photoshop, which, using it's eyedropper tool, will give the RGB values for any color you click on. Sure enough, on the checkerboard, both A and B are exactly 107 each for R, G, and B. And for the last illusion, the center shapes are very close to the same as well (all in the neighborhood of 130).

Fri Aug 05, 09:36:00 PM EDT  

Anonymous trisha bennett said....

hey, thank you alot for helping me out with fouding somethings out bout my homework

Mon Oct 02, 03:12:00 PM EDT  

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Mon Jun 23, 02:33:00 AM EDT  


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