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EICAR Test
The EICAR Test. Have you ever wondered how to test your Antivirus software to ensure it’s proper working? Well here is a quick and easy way to test your antivirus. The process is called EICAR test which will work on any antivirus and was developed by European Institute of Computer Antivirus Research. This process can be used by people, companies and antivirus programmers to test the proper functioning of the antivirus/antimalware software without having to deal with the real computer virus which can cause damage to the computer. Here is a step-by-step procedure to test your antivirus.
1. Open notepad. Copy and paste the following code.
X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
2. Save the file as myfile.com.
3. Now run the antivirus on myfile.com.
If the antivirus is functioning properly on your computer, then it should generate a warning and immediately delete the file upon scanning. Otherwise you may have to re-install your antivirus.
Any antivirus while scanning this file will respond exactly as it will for a genuine virus/malicious code. This test will cause NO damage to your computer even though the antivirus will flag it as a malicious script. Hence it is the safest method to test the proper functioning of any antivirus.
Facebook Hacker Cup 2012 Qualification Round
Facebook held another hacker cup this year again for the second time! What a way to kick start a new year too! I know there have been a couple of visitors around the world coming to my site searching for solutions to this year’s Hacker Cup problems. Unfortunately, I did not participate in this year’s Hacker Cup!
I wish all the hackers all the best in the following rounds! May the best hacker win!
8 Commonly Used Scalable System Design Patterns
Ricky Ho in Scalable System Design Patterns has created a great list of scalability patterns along with very well done explanatory graphics. A summary of the patterns are:
- Load Balancer - a dispatcher determines which worker instance will handle a request based on different policies.
- Scatter and Gather - a dispatcher multicasts requests to all workers in a pool. Each worker will compute a local result and send it back to the dispatcher, who will consolidate them into a single response and then send back to the client.
- Result Cache - a dispatcher will first lookup if the request has been made before and try to find the previous result to return, in order to save the actual execution.
- Shared Space - all workers monitors information from the shared space and contributes partial knowledge back to the blackboard. The information is continuously enriched until a solution is reached.
- Pipe and Filter - all workers connected by pipes across which data flows.
- MapReduce - targets batch jobs where disk I/O is the major bottleneck. It use a distributed file system so that disk I/O can be done in parallel.
- Bulk Synchronous Parallel - a lock-step execution across all workers, coordinated by a master.
- Execution Orchestrator - an intelligent scheduler / orchestrator schedules ready-to-run tasks (based on a dependency graph) across a clusters of dumb workers.
5 Ways to Boost MySQL Scalability
Sean Hall with some really good MySQL advice:
1. Tune those queries
By far the biggest bang for your buck is query optimization. Queries can be functionally correct and meet business requirements without being stress tested for high traffic and high load. This is why we often see clients with growing pains, and scalability challenges as their site becomes more popular. This also makes sense. It wouldn’t necessarily be a good use of time to tune a query for some page off in a remote corner of your site, that didn’t receive real-world traffic. So some amount of reactive tuning is common and appropriate.
Enable the slow query log and watch it. Use mk-query-digest, the great tool from Maatkit to analyze the log. Also make sure the log_queries_not_using_indexes flag is set. Once you’ve found a heavy resource intensive query, optimize it! Use the EXPLAIN facility, use a profiler, look at index usage and create missing indexes, and understand how it is joining and/or sorting.
2. Employ Master-Master Replication
Master-master active-passive replication, otherwise known as circular replication, can be a boon for high availability, but also for scalability. That’s because you immediately have a read-only slave for your application to hit as well. Many web applications exhibit an 80/20 split, where 80% of activity is read or SELECT and the remainder is INSERT and UPDATE. Configure your application to send read traffic to the slave or rearchitect so this is possible. This type of horizontal scalability can then be extended further, adding additional read-only slaves to the infrastructure as necessary.
3. Use Your Memory
It sounds very basic and straightforward, yet there are often details overlooked. At minimum be sure to set these:
- innodb_buffer_pool_size
- key_buffer_size (MyISAM index caching)
- query_cache_size – though beware of issues on large SMP boxes
- thread_cache & table_cache
- innodb_log_file_size & innodb_log_buffer_size
- sort_buffer_size, join_buffer_size, read_buffer_size, read_rnd_buffer_size
- tmp_table_size & max_heap_table_size
4. RAID Your Disk I/O
What is underneath your database? You don’t know? Well please find out! Are you using RAID 5? This is a big performance hit. RAID5 is slow for inserts and updates. It is also almost non-functional during a rebuild if you lose a disk. Very very slow performance. What should I use instead? RAID 10 mirroring and striping, with as many disks as you can fit in your server or raid cabinet. A database does a lot of disk I/O even if you have enough memory to hold the entire database. Why? Sorting requires rearranging rows, as does group by, joins, and so forth. Plus the transaction log is disk I/O as well!
Are you running on EC2? In that case EBS is already fault tolerant and redundant. So give your performance a boost by striping-only across a number of EBS volumes using the Linux md software raid.
5. Tune Key Parameters
These additional parameters can also help a lot with performance.
innodb_flush_log_at_trx_commit=2
This speeds up inserts & updates dramatically by being a little bit lazy about flushing the innodb log buffer. You can do more research yourself but for most environments this setting is recommended.
innodb_file_per_table
Innodb was developed like Oracle with the tablespace model for storage. Apparently the kernel developers didn’t do a very good job. That’s because the default setting to use a single tablespace turns out to be a performance bottleneck. Contention for file descriptors and so forth. This setting makes innodb create tablespace and underlying datafile for each table, just like MyISAM does.
BMTC Posting Order
Alright so my posting order was out yesterday. I was posted to ARTY INSTITUTE with my vocation as ARTY OPR – GUNNERY. Yes I was disappointed when my posting was as men and not to command school.
Looking at it now, positively speaking it may not be that a bad thing being men. Maybe this is God’s plan for me at Arty, who knows. Yeah it’s definitely prestigious, glory and honor and pride being an officer just like my dad rather than men, but with this posting, I can only excel and do my best in whatever I am tasked to do.
Well to all those who didn’t get into command school (OCS / SCS), don’t be disappointed! You can still be a leader in your own vocation, in your own specialty, in your own way! Think about it, having not being chosen for command school doesn’t mean that you aren’t a leader, it’s just HQ’s way of selection which I find it pretty screwed either way. That’s life eventually!
God has provided me with many things since young and he never shortchanged me. I just want to be the best, and do my best in army. But since now I can’t be the best as an officer, I will still do my best as a men. Then again, I have been blessed with a place in NUS Bachelor of Science in Computer Science, my future is secured so it doesn’t matter what I do in the army. Eventually it’s just pride, honor, glory that lives.
Cheers!
Introducing Google Cloud Connect for Microsoft Office
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Teach your old docs new tricks with Google Cloud Connect for Microsoft Office. Google Cloud Connect is a free plugin that improves Microsoft Office 2003, 2007 and 2010 on Windows PCs. It adds simultaneous collaboration, revision history, cloud sync, unique URLs and simple sharing to the Microsoft Word, Excel and Powerpoint applications.
Coke innovation
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When we talk about innovations, Coca Cola company came up with an idea to freeze coke in seconds!
Touch of the Master’s Hand
T’was battered and scarred, and the auctioneer
Thought it scarcely worth his while
To waste much time on the old violin,
But held it up with a smile.
“What am I bidden, good folks,” he cried,
“Who’ll start the bidding for me?”
“A dollar, a dollar,” then, two! Only two?
“Two dollars, and who’ll make it three?
“Three dollars, once; three dollars, twice;
Going for three…” But no,
From the room, far back, a grey haired man
Came forward and picked up the bow;
Then, wiping the dust from the old violin,
And tightening the loose strings,
He played a melody pure and sweet
As a caroling angel sings.
The music ceased, and the auctioneer,
With a voice that was quiet and low,
Said: “What am I bid for the old violin?”
And he held it up with the bow.
“A thousand dollars, and who’ll make it two?
Two thousand! And who’ll make it three?
Three thousand, once; three thousand, twice;
And going and gone,” said he.
The people cheered, but some of them cried,
“We do not quite understand
What changed its worth?” Swift came the reply:
“The touch of a master’s hand.”
And many a man with life out of tune,
And battered and scarred with sin,
Is auctioned cheap to the thoughtless crowd,
Much like the old violin.
A “mess of potage,” a glass of wine;
A game, and he travels on.
He is “going” once, and “going” twice,
He’s “going” and almost “gone.”
But the Master comes and the foolish crowd
Never can quite understand
The worth of a soul and the change that’s wrought
By the touch of the Master’s hand.
“Touch of the Master’s Hand” by Myra Welsh
