100x Faster DB Queries

23 09 2013

http://developers.slashdot.org/story/13/09/23/0939214/oracle-prom+ises-100x-faster-db-queries-with-new-in-memory-option

Oracle Promises 100x Faster DB Queries With New In-Memory Option
Posted by timothy on Monday September 23, 2013 @06:00AM
from the now-report-back-on-the-double dept.

Hugh Pickens DOT Com writes"ZDNet reports that Oracle’s Larry Elison kicked off Oracle OpenWorld 2013 promising a 100x speed-up querying OTLP database or data warehouse batches by means of a ‘dual format’ for both row and column in-memory formats for the same data and table. Using Oracle’s ‘dual-format in-memory database’ option, every transaction is recorded in row format simultaneously with writing the same data into a columnar database. ‘This is pure in-memory columnar technology,’ said Ellison, explaining that means no logging and very little overhead on data changes while the CPU core scans local in-memory columns. Ellison followed up with the introduction of Oracle’s new M6-32 ‘Big Memory Machine,’ touted to be the fastest in-memory machine in the world, hosting 32 terabytes of DRAM memory and up to 384 processor cores with 8-threads per core."

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iOS7 Lockscreen Bypass

20 09 2013

Forbes’ Andy Greenberg wrote an article on the way someone bypass iPhone’s Lockscreen. Here’s the excerpt :


As the video shows, anyone can exploit the bug by swiping up on the lockscreen to access the phone’s “control center,” and then opening the alarm clock. Holding the phone’s sleep button brings up the option to power it off with a swipe. Instead, the intruder can tap “cancel” and double click the home button to enter the phone’s multitasking screen. That offers access to its camera and stored photos, along with the ability to share those photos from the user’s accounts, essentially allowing anyone who grabs the phone to hijack the user’s email, Twitter, Facebook, or Flickr account.

Read more :
http://www.forbes.com/sites/andygreenberg/2013/09/19/ios-7-bug-lets-anyone-bypass-iphones-lockscreen-to-hijack-photos-email-or-twitter/





“ss -n” is faster than “netstat -na” on high load servers?

12 09 2013

# ss -n |grep ESTAB |wc -l
13615

# ss -n |grep CLOSE-WAIT |wc -l
10832

# ss -n |grep FIN-WAIT |wc -l
1976

# ss -V
ss utility, iproute2-ss061002





Float and Double: 1/3 + 2/3 = 0.99999999….

31 07 2013

Rob Eamon wrote about why 1/3 + 2/3 = 0.99999999….

Some excerpts:

Roedy Green’s Java Glossary (http://mindprod.com/jglossfloatingpoint.html) discusses floating point in Java at some length. He offers insight on why developers should not be surprised at the inaccuracy of floating point:

[0.1 is a repeater fraction in binary.] It is like the repeater fraction 1/3 = 0.33333 in base 10. When you add 0.333333… to 0.666666… why are you not astonished to get 0.999999… rather than 1.0, even though you just added 1/3 + 2/3 to get 1? Yet, with Java floating point you are astonished when you add 0.1 + 0.1 and get something other than 0.2.

It is clear that when using float and double types in Java, some care must be taken to ensure proper behavior for the task at hand. For financial applications, where accuracy is paramount, float and double may need to be avoided altogether.

Here’s the full article :

http://www.wmusers.com/ezine/2002oct1_reamon_1.shtml





My fizzbuzz in C

11 04 2013

This is my version of the fizzbuzz test, written in C:

char *arr[] = {"%d\n", "fizz\n", "buzz\n", "fizzbuzz\n"}; 
for (int i=1; i<=100; i++) printf(arr[!(i%3)+2*!(i%5)], i);

or rephrased in a more readable format:

char *arr[] = {"%d\n", "fizz\n", "buzz\n", "fizzbuzz\n"}; 

int i, index;

for (i=1; i<=100; i++)
{
	index = !(i%3) + 2 * !(i%5);
	printf( arr[index], i);
}




tcp-ip How the TIME_WAIT state works

31 01 2013

serverframework.com has written an interesting article about how the TIME_WAIT state really works. The link will get you there:

http://www.serverframework.com/asynchronousevents/2011/01/time-wait-and-its-design-implications-for-protocols-and-scalable-servers.html





slashdot QSL : quantum spin liquid

21 12 2012

http://science.slashdot.org/story/12/12/20/2335226/mit-research-shows-new-magnetic-state-that-could-aid-quantum-computing

MIT Research Shows New Magnetic State That Could Aid Quantum Computing
Posted by samzenpus on Thursday December 20, @08:20PM

alphadogg writes"Researchers at MIT and other institutions have demonstrated a new type of magnetism, only the third kind ever found, and it may find its way into future communications, computing and data storage technologies. Working with a tiny crystal of a rare mineral that took 10 months to make, the researchers for the first time have demonstrated a magnetic state called a QSL (quantum spin liquid), according to MIT physics professor Young Lee. He is the lead author of a paper on their findings, which is set to be published in the journal Nature this week. Theorists had said QSLs might exist, but one had never been demonstrated before. ‘We think it’s pretty important,’ Lee said, adding that he would let his peers be the ultimate judges."