Hobart is currently certified at Journeyer level.

Name: Jon Bailey
Member since: 2000-12-28 17:26:40
Last Login: 2009-06-05 13:16:23

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Homepage: http://jb.org/


"The best thing for being sad," replied Merlin, beginning to puff and blow, "is to learn something. That's the only thing that never fails. You may grow old and trembling in your anatomies, you may lie awake at night listening to the disorder of your veins, you may miss your only love, you may see the world about you devastated by evil lunatics, or know your honour trampled in the sewers of baser minds. There is only one thing for it then -- to learn. Learn why the world wags and what wags it. That is the only thing which the mind can never exhaust, never alienate, never be tortured by, never fear or distrust, and never dream of regretting. Learning is the only thing for you. Look what a lot of things there are to learn." -- T.H. White, "The Once and Future King"

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4-disk raidz vs 3-disk raidz vs 2-disk mirror

Benchmarked three different volumes (ZFS on Linux) from a Windows client.

Conclusion: At the mere speed of Gigabit Ethernet, there's no appreciable speed difference.

Syndicated 2015-10-01 21:28:52 from jon's blog

"Stupid, STUPID Unix creatures!"

tl;dr: Wrap your shell script loops in (subshells)

ProTip: A task running in a shell script's 'for' loop that are paused by signal TSTP (that is, hitting ^Z) and restarted (with 'fg' or '%') will keep going, but the loop will have been broken and not continue (bash behavior) or the command sequence will continue as though it had completed ('dash' and probably other Bourne shells behavior). I've tested in bash and dash.

This doesn't work when interrupted by ^Z:

$ for X in 1 2 3; echo Iteration $X; sleep 5; echo Iteration $X complete; done

This does:

$ (for X in 1 2 3; echo Iteration $X; sleep 5; echo Iteration $X complete; done)

This sort of thing doesn't happen often but when you're looping through commands that take ~6h to complete and find you've lost the output, it's frustrating. :)

Syndicated 2015-10-01 13:38:13 from jon's blog

Atari 8-bit "Archimedes Spiral" demo - Found again!

Sometimes you stumble upon what you were looking for by accident ...

When I was 9 or 10 years old, I didn't have a modem, much less access to the Internet. The few computer magazines I had, I read over and over - and would have to type in games from program listings. I remembered typing in a BASIC program full of complicated math I didn't understand. The resulting program would take hours to run, but produced an impressive 3-D wireframe image. (With hidden line removal!)

7 years ago (mid-2008) I decided to poke around the Internet and ask in various places if anyone had seen it ... with no luck.

I had a bit of luck a year later, and posted my findings here on LiveJournal.

Today I was reading through some .PDFs of old Atari magazines, not even thinking of this, when lo-and-behold, there was the article. Hazzoo-huzzah! It turned out not to be MACE Journal or Compute, but a 1982 issue of ANALOG Computing - #7, the one with the awesome Blade-Runner inspired cover art. Many thanks to Charles Bachand, and editor Lee Pappas for the article!

I wonder if Charles is reachable... and if he remembers where he got the code for the demo... The image I found before (in a Commodore ad) appears in Compute! issue 12 from May 1981 ... the ad is from Micro Technology Unlimited ... and that same issue has a screen-dump utility by that company's employee, Martin J. Cohen, Ph.D. who is the author of their Keyword Graphics Package. Hmm! (Neat: in that issue he thanks Gregory Yob for help in part of his code!)

Those with too much time on their hands are encouraged to look at the issue on Internet Archive - A.N.A.L.O.G. Computing magazine, issue 7 (1982) pp60-61. (Thanks to Brewster Kahle, Jason Scott, and others for their work there!)

Analog_Computing_07_1982-p60 Analog_Computing_07_1982-p61
A.N.A.L.O.G. Computing magazine, issue 7 (1982) pp60-61
by Charles Bachand

This article contains a graphics program called "Archimedes Spiral". The program, although quite short, takes nearly three hours to run! This is definitely not a quick demo. (To produce the transparent version of the spiral, delete line 240.)(It still looks like a hat to me. Ed.)

110 REM 
130 REM 
140 GRAPHICS 8+16:SETCOLOR 2,0,0
150 XP=144:XR=4.71238905:XF=XR/XP
160 FOR ZI=-64 TO 64
170 ZT=ZI*2.25:ZS=ZT*ZT
180 XL=INT(SQR(20736-ZS)+0.5)
210 YY=(SIN(XT)+SIN(XT*3)*0.4)*56
220 X1=XI+ZI+160:Y1=90-YY+ZI
230 TRAP 250:COLOR 1:PLOT X1,Y1
240 COLOR 0:PLOT X1,Y1+1:DRAWTO X1,191
260 GOTO 260

It would be so much simpler if you could hand out a hardcopy of the graphics to demonstrate your prowess with the computer. Your friends will be doing cartwheels and going hazoo-huzzah over your printing expertise. (Hazoo-huzzah?! Ed.)

(Ed. Note: No one here at A.N.A.L.O.G is responsihle for Charlie's state of mind when he writes these non-tutorials. Just thought you people would like to know.)

Syndicated 2015-02-22 05:02:56 from jon's blog

Rosetta / Philae comet landing livestream


Fingers crossed for the #forth powered lander :)

Syndicated 2014-11-12 15:03:34 from jon's blog

GMail locked down IMAP access at some point.


  • If you don't have IMAP + OAuth 2 you're locked out. Unless:
  • You change a Big Scary Setting "Allow less secure apps". The activation of which also generates a Big Scary Email to let you know you've done it. But then:
  • Your failed attempts triggered another lock on your account, which you need to inspect the IMAP negotiation to see. The first claims "Web login required!¬†go to http://blahblah/100char-long-url", but, surprise! visiting the URL doesn't unlock you.
  • The second directs you to https://support.google.com/mail/answer/78754 where you learn about https://www.google.com/accounts/DisplayUnlockCaptcha which, when visited, does NOT display a CAPTCHA, but does unlock your account.
  • OAuth 2 is so ridiculously overdesigned the main editor of the spec loudly quit.
  • All of this could have been handled using client side certificates, without requiring any changes to the @#$% mail clients.
Version: GnuPG v1
Some relevant URLs:

Syndicated 2014-10-29 20:36:11 from jon's blog

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