If you're starting out trying to build your first (or second, or whatever) parallel program, I've found that the Lawrence Livermore National Lab keeps a very nice page on High Performance Computing. It looks like it's maintained by a guy named Blaise Barney (awesome name). He does a great job of organizing it and writing the tutorials on various topics.
Lately, I've been using it extensively as I build my first significant pthread application. The tutorial on that topic has handy links to the original POSIX documentation and the provided examples are really well done, making it easy to get coding on your own project.
The site also has information and tutorials on other stuff like MPI and OpenMP, as well as documentation describing the pros and cons of all of these parallel programming tools. Not much else to say on the topic, just wanted to document it for myself and maybe make it easier for someone else to find it in the future.
Showing posts with label software. Show all posts
Showing posts with label software. Show all posts
Friday, June 27, 2008
Saturday, June 14, 2008
Win32/Glenwiry.P : The Final Chapter
Well, this is the conclusion to my epic glenwiry.P trilogy (in case you missed it, the first two posts were a roller coaster of emotion, drama and raw excitement). I noticed that my latest anti-virus definitions were downloaded when I fired up the computer this morning (8:20am PDT). So I tried the following:
So chances are, if you never had the glenwiry.p problem, you aren't going to see it anytime soon because the current definitions don't produce a false positive, and if you did have the glenwiry.p problem, you can probably go ahead an restore those files. Again, this is just based on my own experience: do whatever you want to do at your own risk. I am not a security expert, I just play one on the web.
- Disconnected my router from the Internet.
- Went to the "Tools" tab of the CA antivirus software.
- Clicked "Quarantined Items."
- Restored the three "wextract.exe" files that were quarantined Thursday night.
- Ran a virus scan of the WINDOWS/system32 folder.
- Did a happy dance.
So chances are, if you never had the glenwiry.p problem, you aren't going to see it anytime soon because the current definitions don't produce a false positive, and if you did have the glenwiry.p problem, you can probably go ahead an restore those files. Again, this is just based on my own experience: do whatever you want to do at your own risk. I am not a security expert, I just play one on the web.
Friday, June 13, 2008
Win32/Glenwiry.P follow-up
Just thought I'd post a little follow-up to my post from yesterday. I am still not completely comfortable saying I'm 100% certain that the Computer Associates quarantine of wextract.exe is a false positive, but based on everything I have read and know, it seems like a false positive is most likely. I'll probably leave those files quarantined until either CA issues a fix or my system suffers for not having it available.
I've seen some folks saying it likely ISN'T a false positive (how's that for a weird double negative) because ZoneAlarm has been noted as flagging these files too. Well, turns out that ZA uses the CA anti-virus engine. At least that's what CNET said last summer. If that is still true, I think it provides even more evidence that we are just looking at a bad definition in the CA tools. If I'm wrong about the ZA-CA connection, I hope someone lets me know.
What is really bothering me now is that CA released a fix for a presumable trojan before it was even known to exist in the wild. This is evidenced by the complete lack of any Google hits on Glenwiry.P before this antivirus definition update last night by CA. Even CA's own website doesn't have any information on the Glenwiry.P threat as of the time of this posting. If that's the case, how is it being caught by their antvirus tools? Perhaps they released the fix There has always been speculation and conspiracy theories that antivirus companies may actually create viruses/threats. An interesting business model, indeed. Though, it is a neat trick to catch a "threat" before anyone has ever heard of it, even yourself. But, hey, what the heck do I know? I'm just a once-in-a-while blogger.
I've seen some folks saying it likely ISN'T a false positive (how's that for a weird double negative) because ZoneAlarm has been noted as flagging these files too. Well, turns out that ZA uses the CA anti-virus engine. At least that's what CNET said last summer. If that is still true, I think it provides even more evidence that we are just looking at a bad definition in the CA tools. If I'm wrong about the ZA-CA connection, I hope someone lets me know.
What is really bothering me now is that CA released a fix for a presumable trojan before it was even known to exist in the wild. This is evidenced by the complete lack of any Google hits on Glenwiry.P before this antivirus definition update last night by CA. Even CA's own website doesn't have any information on the Glenwiry.P threat as of the time of this posting. If that's the case, how is it being caught by their antvirus tools? Perhaps they released the fix There has always been speculation and conspiracy theories that antivirus companies may actually create viruses/threats. An interesting business model, indeed. Though, it is a neat trick to catch a "threat" before anyone has ever heard of it, even yourself. But, hey, what the heck do I know? I'm just a once-in-a-while blogger.
Thursday, June 12, 2008
win32/Glenwiry.p fiasco
So I think the most recent update of Computer Associate's virus scan definitions is giving false positives on wextract.exe. If you have real-time scan activated you'll probably get C:/WINDOWS/system32/wextract.exe and C:/WINDOWS/system32/dllcache/wextract.exe quarantined by your anti-virus software. This might prompt Windows to put up a red flag and demand that you insert your operating system install disk. Not sure yet what the best fix is, so I am going to wait out til the next update from CA which should fix the problem. If that doesn't happen soon or my system has problems due to the quarantined/missing wextract.exe, I will probably restore the quarantined item using CA's tools that come with the anti-virus software.
This all did give me quite a scare though since I pride myself on keeping as secure a system as I can considering I am running Windows. Anyway, I hope this post helps somebody not feel as freaked out as I was initially. There isn't much info online as of now.
Oh, as a side note, I would be careful about going to sites you might find by searching for glenwiry. I think many of them are bogus. If you do go to one by mistake, don't try and click any videos posted there. And if you browser goes into a pop-up hell, you should ctrl-alt-del and kill the browser process. That should get you out of the pop-up carousel.
If I learn anything new tomorrow I'll try and update here, but as you can see by my post history, I am not the most prolific blogger.
This all did give me quite a scare though since I pride myself on keeping as secure a system as I can considering I am running Windows. Anyway, I hope this post helps somebody not feel as freaked out as I was initially. There isn't much info online as of now.
Oh, as a side note, I would be careful about going to sites you might find by searching for glenwiry. I think many of them are bogus. If you do go to one by mistake, don't try and click any videos posted there. And if you browser goes into a pop-up hell, you should ctrl-alt-del and kill the browser process. That should get you out of the pop-up carousel.
If I learn anything new tomorrow I'll try and update here, but as you can see by my post history, I am not the most prolific blogger.
Monday, February 19, 2007
Battling the Audiophase mp3 player
Just bought a cheapo mp3 player a week ago: the Audiophase KP512. I think the information here is probably useful to any of the Audiophase mp3 players (I know there is a 1GB (KP1000?) version, probably others).
I was able to sync up some files with Windows Media Player 10.5 and the player worked well for a couple days. Then I added a couple more files and when I next tried to use the player, it told me there were 'no files'. Lame. I checked the information available on the player itself and it noted that there were 300+MB of files on it--my songs. Lamer.
So when I got home I did a little bit of research on the inter-webs and found out that it wasn't a unique problem. But beyond the advice given there, I didn't find much else. So, if anything that I have gone through can help anyone else, here goes....
I used the Windows Media Player to re-format the mp3 player. Now I realize that if you want to format your player, just delete everything by hand as that's all WMP does. Thinking that maybe WMP was part of the problem (check some of this discussion), I downloaded MediaMonkey (free and very well done) to do my syncing. Had the same issues, but I do like MediaMonkey.
Finally broke down and tried the RealPlayer to sync things. While I found some other issues with that (said some mp3 files weren't transferable for some reason), the process worked. I think that the issue MIGHT have to do with how folders are created in the syncing process. RealPlayer seems to just toss all the files into the root directory. This is fine for this size player, since there won't be over 256 songs on it. 256 is the limit for files in a directory I think. I'll need to experiment some more with the other players to see if this is actually the issue.
Another work around, which may be a little annoying is to just copy the files as if the player is a USB key or some other drive. That works too. Like I said, some more experimentation may be in order to find out the real issue. I don't want to temp fate just yet though since I actually have my music ready to listen to. That fact may tempt me to exercise tomorrow!
Oh, and the 'tech support' for Audiophase as listed in the user manual just goes to some guy's desk. I don't think leaving him a message is really doing any good. If he isn't tech actually tech support, I am sure he is kinda sick of those calls.
I was able to sync up some files with Windows Media Player 10.5 and the player worked well for a couple days. Then I added a couple more files and when I next tried to use the player, it told me there were 'no files'. Lame. I checked the information available on the player itself and it noted that there were 300+MB of files on it--my songs. Lamer.
So when I got home I did a little bit of research on the inter-webs and found out that it wasn't a unique problem. But beyond the advice given there, I didn't find much else. So, if anything that I have gone through can help anyone else, here goes....
I used the Windows Media Player to re-format the mp3 player. Now I realize that if you want to format your player, just delete everything by hand as that's all WMP does. Thinking that maybe WMP was part of the problem (check some of this discussion), I downloaded MediaMonkey (free and very well done) to do my syncing. Had the same issues, but I do like MediaMonkey.
Finally broke down and tried the RealPlayer to sync things. While I found some other issues with that (said some mp3 files weren't transferable for some reason), the process worked. I think that the issue MIGHT have to do with how folders are created in the syncing process. RealPlayer seems to just toss all the files into the root directory. This is fine for this size player, since there won't be over 256 songs on it. 256 is the limit for files in a directory I think. I'll need to experiment some more with the other players to see if this is actually the issue.
Another work around, which may be a little annoying is to just copy the files as if the player is a USB key or some other drive. That works too. Like I said, some more experimentation may be in order to find out the real issue. I don't want to temp fate just yet though since I actually have my music ready to listen to. That fact may tempt me to exercise tomorrow!
Oh, and the 'tech support' for Audiophase as listed in the user manual just goes to some guy's desk. I don't think leaving him a message is really doing any good. If he isn't tech actually tech support, I am sure he is kinda sick of those calls.
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