blog of Intrepid Wanderer

This is the weblog of Intrepid Wanderer. You never know what you might find here; graphic descriptions of bodily functions, computer programming secrets, proselytizing for the antichrist, miscellaneous ranting and kvetching, valuable information on living off the land... if you don't share my rather weird interests you may want to try slashdot instead.

You can consider my Del.icio.us links an extension to my blog, as are my LifeTango goals and my other to-do items. My to-buy list is also public, but only for sharing any useful ideas that might be there; I'm not requesting charity, neither do I offer it.

You can find me easily in google searches, as jcomeau, jcomeau_ictx, or jcomeauictx. There are lots of other jcomeaus, but AFAIK I'm the only jcomeau_ictx out there so far.

If you want to comment on anything you see here, go ahead and email me, jc.unternet.net. You know what to do with the first dot. Make the 'subject' line something reasonably intelligent-looking or it goes plunk! into the spambasket unread.

This page generally sucks less using Mozilla Firefox.

2009-11-06-2114Z

The glasses I bought for $8 + $4.95 shipping from Zenni Optical work great. I got them last Saturday and have used them for brief periods, and it's tempting to wear them all the time outdoors, to see all the detail I've been missing. But I don't want to risk long-term damage to my eyes.

These $8 glasses, offered on several websites now, are an incredible bargain, and I wonder how much longer the likes of Lenscrafters can stay in business once the word gets out.

Made a Jambalaya last night from Emeril Lagasse's recipe, and it was pretty damned good. I thought I could double the recipe, because I didn't believe it was 4 servings as stated, but I realized once I got going that I couldn't double the rice and chicken stock. So it had double the meat and veggies and spices. Can't say I regret the mistake, especially since two people ate it all in one sitting.

2009-11-01-0926Z

Still haven't found a stack diagram of what Linux hands over to a signal handler. What I've managed to piece together, possibly accurately, is this (offsets indicate dwords, multiply by 4 for byte offset):

Offset   Contents          Example
0        return addr       0x0fffe420
1        signal number     0xb (11=segfault)
2        GS (?)            0 (start of interrupted task's registers)
3        FS (?)            0
4        ES (?)            0x7b
5        DS (?)            0x7b
6        EDI               0x08088000
7        ESI               0
8        EBP               0
9        ESP               0xbffffcbc
10       EBX               2
11       EDX               0xc
12       ECX               0x10
13       EAX               0xa
14       ?                 0xe
15       ?                 4
16       addr that faulted 0x08048131  (rep scasb)
17       CS (?)            0x73
18       eflags            0x00010206
19       ESP               0xbffffcbc
20       SS                0x7b

The signal number is also provided in EAX. All the above registers, including the flags and return address, can be modified by the handler. Very ugly and nonportable, but magical in its possibilities.

My brilliant idea of speeding up I/O using memory protection and signal handling failed. I still believe it has possibilities, but I need to find a way to profile what's going on.

jc blog - tales of a modern-day nomadic hunter-gatherer

2009-11-06-2114Z

2009-11-01-0926Z