Linux and Unix Training in San Bernardino, California

In programming, memory leaks are a common issue, and it occurs when a computer uses memory but does not give it back to the operating system. Experienced programmers have the ability to diagnose a leak based on the symptoms. Some believe every undesired increase in memory usage is a memory leak, but this is not an accurate representation of a leak. Certain leaks only run for a short time and are virtually undetectable.

Memory Leak Consequences

Applications that suffer severe memory leaks will eventually exceed the memory resulting in a severe slowdown or a termination of the application.

How to Protect Code from Memory Leaks?

Preventing memory leaks in the first place is more convenient than trying to locate the leak later. To do this, you can use defensive programming techniques such as smart pointers for C++. A smart pointer is safer than a raw pointer because it provides augmented behavior that raw pointers do not have. This includes garbage collection and checking for nulls.

If you are going to use a raw pointer, avoid operations that are dangerous for specific contexts. This means pointer arithmetic and pointer copying. Smart pointers use a reference count for the object being referred to. Once the reference count reaches zero, the excess goes into garbage collection. The most commonly used smart pointer is shared_ptr from the TR1 extensions of the C++ standard library.

Static Analysis

The second approach to memory leaks is referred to as static analysis and attempts to detect errors in your source-code. CodeSonar is one of the effective tools for detection. It provides checkers for the Power of Ten coding rules, and it is especially competent at procedural analysis. However, some might find it lagging for bigger code bases.

How to Handle a Memory Leak

For some memory leaks, the only solution is to read through the code to find and correct the error. Another one of the common approaches to C++ is to use RAII, which an acronym for Resource Acquisition Is Initialization. This approach means associating scoped objects using the acquired resources, which automatically releases the resources when the objects are no longer within scope. RAII has the advantage of knowing when objects exist and when they do not. This gives it a distinct advantage over garbage collection. Regardless, RAII is not always recommended because some situations require ordinary pointers to manage raw memory and increase performance. Use it with caution.

The Most Serious Leaks

Urgency of a leak depends on the situation, and where the leak has occurred in the operating system. Additionally, it becomes more urgent if the leak occurs where the memory is limited such as in embedded systems and portable devices.

To protect code from memory leaks, people have to stay vigilant and avoid codes that could result in a leak. Memory leaks continue until someone turns the system off, which makes the memory available again, but the slow process of a leak can eventually prejudice a machine that normally runs correctly.

The Five Principles of Performance

In Demand IT Skills

Computer Hackers, a Tricks of the Trade Overview

[Mar, 09, 2014] |
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With stiff penalties for being caught and the whiff of secretive underground or even nefarious acts, computer hacking can be seen as a somewhat dubious pursuit. Not all hackers operate with the motive of emptying your Paypal account, however; there are many hackers who utilize their skills to aid companies in locating security flaws ("penetration testing") or engage in hacking with the goal of becoming cyber-freedom-fighters that champion simple human freedoms, such as the right to free speech.

Computer hacking is as much an art as it is a skill. At its simplest distillation, hacking is the systematic search for chinks in programming armor. While advanced problem-solving, intuition and sophisticated understanding of programming languages are a distinct advantage, there does exist a number of push-button programs that computing wizards have written allowing those less sophisticated in the art of hacking to break into remote computers in a variety of ways. Because of this new ubiquity, today's hackers no longer need to be a programming Wunderkind; they simply need to know where to download software and be able to turn on a computer. It really is that simple and the implications can be disturbing.

Phishing, Push-Button Programs and Brute Force Tactics

There's no need to crack a company's firewall if you have direct physical access to their computers. One aspect of hacking is the impersonation of an employee or service worker with the goal of gaining access to a company's database, where the hacker can then unleash whatever havoc he or she has planned into the system. Another is to engage in simple phishing techniques, such as impersonating an employee who forgot their password and needs help logging into the system.

Because such impersonations often fail thanks to companies becoming more security-conscious, taking over operations of a computer remotely is often the preferred method of gaining access. Such attempts can be facilitated in a variety of ways. One is the brute-force method, in which a program such as SQLmap, Nmap or Burpsuite is used; running one of these programs is analogous to trying every doorknob in a neighborhood to see which house is unlocked. Using a variety of different parameters, these programs can find access to a vulnerable computer or network in less than a minute.

Hackers can also attempt to gain access with a program like Metasploit. With literally a few clicks of a mouse, access to a remote and vulnerable computer can be achieved by a relative newbie. With a related hacking aid, called Meterpreter, a backdoor is created that allows access into an operating system. It does not install itself onto the remote computer, running instead using the computer's memory; in fact, Meterpreter can hide itself inside the operations of a perfectly valid program, so it cannot be detected even by sophisticated programmers. Once engaged, it allows a remote user carte blanche access to the system in question.

Where to Learn the Art of Hacking

Of course, for those who wish to learn the actual skills rather than download someone else's hack, there are a number of practice sites that pose an increasingly difficult set of challenges intended to train neophytes in the art of hacking. For example, Hack This Site starts beginners with the goal of cracking simple flaws in coding scripts or software such as HTML, Unix, Javascript and Apache. Their structured series of tests increase in complexity, incorporating real-word scenarios and even old-fashioned "phone phreaking" challenges that recall the bygone golden age of hacking skills displayed by Matthew Broderick in "WarGames."

Using just these simple tools and free practice sites, beginners have a powerful array of hacking resources just a simple mouse click away.

What Should I Focus On To Become Good C++ Developer?

[Apr, 01, 2020] |
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The original article was posted by Michael Veksler on Quora

A very well known fact is that code is written once, but it is read many times. This means that a good developer, in any language, writes understandable code. Writing understandable code is not always easy, and takes practice. The difficult part, is that you read what you have just written and it makes perfect sense to you, but a year later you curse the idiot who wrote that code, without realizing it was you.

The best way to learn how to write readable code, is to collaborate with others. Other people will spot badly written code, faster than the author. There are plenty of open source projects, which you can start working on and learn from more experienced programmers.

Readability is a tricky thing, and involves several aspects:

Never surprise the reader of your code, even if it will be you a year from now. For example, don’t call a function max() when sometimes it returns the minimum().
Be consistent, and use the same conventions throughout your code. Not only the same naming conventions, and the same indentation, but also the same semantics. If, for example, most of your functions return a negative value for failure and a positive for success, then avoid writing functions that return false on failure.
Write short functions, so that they fit your screen. I hate strict rules, since there are always exceptions, but from my experience you can almost always write functions short enough to fit your screen. Throughout my carrier I had only a few cases when writing short function was either impossible, or resulted in much worse code.
Use descriptive names, unless this is one of those standard names, such as i or it in a loop. Don’t make the name too long, on one hand, but don’t make it cryptic on the other.
Define function names by what they do, not by what they are used for or how they are implemented. If you name functions by what they do, then code will be much more readable, and much more reusable.
Avoid global state as much as you can. Global variables, and sometimes attributes in an object, are difficult to reason about. It is difficult to understand why such global state changes, when it does, and requires a lot of debugging.
As Donald Knuth wrote in one of his papers: “Early optimization is the root of all evil”. Meaning, write for readability first, optimize later.
The opposite of the previous rule: if you have an alternative which has similar readability, but lower complexity, use it. Also, if you have a polynomial alternative to your exponential algorithm (when N > 10), you should use that.

Use standard library whenever it makes your code shorter; don’t implement everything yourself. External libraries are more problematic, and are both good and bad. With external libraries, such as boost, you can save a lot of work. You should really learn boost, with the added benefit that the c++ standard gets more and more form boost. The negative with boost is that it changes over time, and code that works today may break tomorrow. Also, if you try to combine a third-party library, which uses a specific version of boost, it may break with your current version of boost. This does not happen often, but it may.

Don’t blindly use C++ standard library without understanding what it does - learn it. You look at std::vector::push_back() documentation at it tells you that its complexity is O(1), amortized. What does that mean? How does it work? What are benefits and what are the costs? Same with std::map, and with std::unordered_map. Knowing the difference between these two maps, you’d know when to use each one of them.

Never call new or delete directly, use std::make_unique and [cost c++]std::make_shared[/code] instead. Try to implement usique_ptr, shared_ptr, weak_ptr yourself, in order to understand what they actually do. People do dumb things with these types, since they don’t understand what these pointers are.

Every time you look at a new class or function, in boost or in std, ask yourself “why is it done this way and not another?”. It will help you understand trade-offs in software development, and will help you use the right tool for your job. Don’t be afraid to peek into the source of boost and the std, and try to understand how it works. It will not be easy, at first, but you will learn a lot.

Know what complexity is, and how to calculate it. Avoid exponential and cubic complexity, unless you know your N is very low, and will always stay low.

Learn data-structures and algorithms, and know them. Many people think that it is simply a wasted time, since all data-structures are implemented in standard libraries, but this is not as simple as that. By understanding data-structures, you’d find it easier to pick the right library. Also, believe it or now, after 25 years since I learned data-structures, I still use this knowledge. Half a year ago I had to implemented a hash table, since I needed fast serialization capability which the available libraries did not provide. Now I am writing some sort of interval-btree, since using std::map, for the same purpose, turned up to be very very slow, and the performance bottleneck of my code.

Notice that you can’t just find interval-btree on Wikipedia, or stack-overflow. The closest thing you can find is Interval tree, but it has some performance drawbacks. So how can you implement an interval-btree, unless you know what a btree is and what an interval-tree is? I strongly suggest, again, that you learn and remember data-structures.

These are the most important things, which will make you a better programmer. The other things will follow.

The importance of exercise for IT professionals

[May, 16, 2014] |
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Programmers often tend to be sedentary people. Sitting in a chair and pressing keys, testing code, and planning out one logical step-wise strategy after another to get the computer to process data the way you want it to is just what life as a programmer is all about. But, is being too sedentary hindering a programmers max potential? In other words, will getting up, moving around, and getting the blood pumping make us better programmers? To answer this question more efficiently, we will need to consider the impact of exercise on various aspects of programming.

Alertness And Focus

It is no surprise that working up a sweat makes the mind wake up and become more alert. As the blood starts pumping, the body physically reacts in ways that helps the mind to better focus. And improving our focus might make us better programmers in the sense that we are more able to wrap our mind around a problem and deal with it more efficiently than if we feel sluggish and not so alert. However, improving one's focus with exercise can be augmented by taking such vitamins as B6, Coleen, and eating more saturated fats rather than so many sugars. Exercise alone may be a good start, but it is important to realize that the impact of exercise on overall focus can be enhanced when combined with other dietary practices. However, it never hurts to begin a day of programming with fifteen minutes of rigorous workout to give the mind a little extra push.

Increase In Intellect

Does exercise cause a programmer to become a smarter programmer? This is perhaps a trickier question. In some sense, it might seem as if exercise makes us more intelligent. But, this may be more because our focus is sharper than because of any increase in actual knowledge. For example, if you don't know how to program in Python, it is highly doubtful that exercising harder will all of a sudden transfer such insights directly to your brain. However, exercise might have another indirect impact on a programmer’s intellect that will help them to become a better programmer. The more a person exercises, the more stamina and energy they will tend to have, as compared to programmers who never exercise all that much. That additional energy and stamina might help a programmer to be able to push themselves to learn things more efficiently, simply because they aren't getting tired as much as they study new languages or coding techniques. If you have more energy and stamina throughout the day, you will likely be more productive as a programmer as well. Greater productivity can often make one program better simply because they actually push themselves to finish projects. Other programmers who do not exercise on a regular basis may simply lack the energy, stamina, and motivation to follow through and bring their programming projects to completion.

Memory

The ability to remember things and recall them quickly is key to being an efficient programmer. Getting up and getting real exercise may be central to making sure that one does not lose control of these cognitive abilities. According to the New York Times, article, Getting a Brain Boost Through Exercise, recent research studies on mice and humans have shown that, in both cases, exercise does in fact appear to promote better memory function as well as other cognitive factors like spacial sense. (1) Consequently, if a person intends to be a programmer for a long time and wants their mind to be able to remember things and recall them more easily, then exercise may need to become an essential part of such a programmer's daily routine.

As much as one might want to resist the need for exercise and be sedentary programmers, the simple fact is that exercise very well could improve our ability to program in numerous ways. More importantly, exercise is critical to improving and maintaining good health overall. Even if a person does not have much time to get up and move around during the day, there are exercises that one can do while sitting, which would be better to do than no exercise at all.

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Tech Life in California

Largely influenced by several immigrant populations California has experienced several technological, entertainment and economic booms over the years. As for technology, Silicon Valley, in the southern part of San Francisco is an integral part of the world?s innovators, high-tech businesses and a myriad of techie start-ups. It also accounts for 1/3rd of all venture capital investments.

Those who think they know it all are very annoying to those of us who do. ~ Robert K. Muller

other Learning Options

Software developers near San Bernardino have ample opportunities to meet like minded techie individuals, collaborate and expend their career choices by participating in Meet-Up Groups. The following is a list of Technology Groups in the area.

BBDevSF - SF BlackBerry Developers Group · Tech In Motion: Orange County · Silicon Valley Entrepreneurs & Startups ·

Fortune 500 and 1000 companies in California that offer opportunities for Linux Unix developers

Company Name	City	Industry	Secondary Industry
Mattel, Inc.	El Segundo	Retail	Sporting Goods, Hobby, Book, and Music Stores
Spectrum Group International, Inc.	Irvine	Retail	Retail Other
Chevron Corp	San Ramon	Energy and Utilities	Gasoline and Oil Refineries
Jacobs Engineering Group, Inc.	Pasadena	Real Estate and Construction	Construction and Remodeling
eBay Inc.	San Jose	Software and Internet	E-commerce and Internet Businesses
Broadcom Corporation	Irvine	Computers and Electronics	Semiconductor and Microchip Manufacturing
Franklin Templeton Investments	San Mateo	Financial Services	Investment Banking and Venture Capital
Pacific Life Insurance Company	Newport Beach	Financial Services	Insurance and Risk Management
Tutor Perini Corporation	Sylmar	Real Estate and Construction	Construction and Remodeling
SYNNEX Corporation	Fremont	Software and Internet	Data Analytics, Management and Storage
Core-Mark International Inc	South San Francisco	Manufacturing	Food and Dairy Product Manufacturing and Packaging
Occidental Petroleum Corporation	Los Angeles	Manufacturing	Chemicals and Petrochemicals
Yahoo!, Inc.	Sunnyvale	Software and Internet	Software and Internet Other
Edison International	Rosemead	Energy and Utilities	Gas and Electric Utilities
Ingram Micro, Inc.	Santa Ana	Computers and Electronics	Consumer Electronics, Parts and Repair
Safeway, Inc.	Pleasanton	Retail	Grocery and Specialty Food Stores
Gilead Sciences, Inc.	San Mateo	Healthcare, Pharmaceuticals and Biotech	Pharmaceuticals
AECOM Technology Corporation	Los Angeles	Real Estate and Construction	Architecture,Engineering and Design
Reliance Steel and Aluminum	Los Angeles	Manufacturing	Metals Manufacturing
Live Nation, Inc.	Beverly Hills	Media and Entertainment	Performing Arts
Advanced Micro Devices, Inc.	Sunnyvale	Computers and Electronics	Semiconductor and Microchip Manufacturing
Pacific Gas and Electric Corp	San Francisco	Energy and Utilities	Gas and Electric Utilities
Electronic Arts Inc.	Redwood City	Software and Internet	Games and Gaming
Oracle Corporation	Redwood City	Software and Internet	Software and Internet Other
Symantec Corporation	Mountain View	Software and Internet	Data Analytics, Management and Storage
Dole Food Company, Inc.	Thousand Oaks	Manufacturing	Food and Dairy Product Manufacturing and Packaging
CBRE Group, Inc.	Los Angeles	Real Estate and Construction	Real Estate Investment and Development
First American Financial Corporation	Santa Ana	Financial Services	Financial Services Other
The Gap, Inc.	San Francisco	Retail	Clothing and Shoes Stores
Ross Stores, Inc.	Pleasanton	Retail	Clothing and Shoes Stores
Qualcomm Incorporated	San Diego	Telecommunications	Wireless and Mobile
Charles Schwab Corporation	San Francisco	Financial Services	Securities Agents and Brokers
Sempra Energy	San Diego	Energy and Utilities	Gas and Electric Utilities
Western Digital Corporation	Irvine	Computers and Electronics	Consumer Electronics, Parts and Repair
Health Net, Inc.	Woodland Hills	Healthcare, Pharmaceuticals and Biotech	Healthcare, Pharmaceuticals, and Biotech Other
Allergan, Inc.	Irvine	Healthcare, Pharmaceuticals and Biotech	Biotechnology
The Walt Disney Company	Burbank	Media and Entertainment	Motion Picture and Recording Producers
Hewlett-Packard Company	Palo Alto	Computers and Electronics	Consumer Electronics, Parts and Repair
URS Corporation	San Francisco	Real Estate and Construction	Architecture,Engineering and Design
Cisco Systems, Inc.	San Jose	Computers and Electronics	Networking Equipment and Systems
Wells Fargo and Company	San Francisco	Financial Services	Banks
Intel Corporation	Santa Clara	Computers and Electronics	Semiconductor and Microchip Manufacturing
Applied Materials, Inc.	Santa Clara	Computers and Electronics	Semiconductor and Microchip Manufacturing
Sanmina Corporation	San Jose	Computers and Electronics	Semiconductor and Microchip Manufacturing
Agilent Technologies, Inc.	Santa Clara	Telecommunications	Telecommunications Equipment and Accessories
Avery Dennison Corporation	Pasadena	Manufacturing	Paper and Paper Products
The Clorox Company	Oakland	Manufacturing	Chemicals and Petrochemicals
Apple Inc.	Cupertino	Computers and Electronics	Consumer Electronics, Parts and Repair
Amgen Inc	Thousand Oaks	Healthcare, Pharmaceuticals and Biotech	Biotechnology
McKesson Corporation	San Francisco	Healthcare, Pharmaceuticals and Biotech	Pharmaceuticals
DIRECTV	El Segundo	Telecommunications	Cable Television Providers
Visa, Inc.	San Mateo	Financial Services	Credit Cards and Related Services
Google, Inc.	Mountain View	Software and Internet	E-commerce and Internet Businesses

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the hartmann software group advantage

why take Linux Unix Training with the hartmann software group?

A successful career as a software developer or other IT professional requires a solid understanding of software development processes, design patterns, enterprise application architectures, web services, security, networking and much more. The progression from novice to expert can be a daunting endeavor; this is especially true when traversing the learning curve without expert guidance. A common experience is that too much time and money is wasted on a career plan or application due to misinformation.

The Hartmann Software Group understands these issues and addresses them and others during any training engagement. Although no IT educational institution can guarantee career or application development success, HSG can get you closer to your goals at a far faster rate than self paced learning and, arguably, than the competition. Here are the reasons why we are so successful at teaching:

Learn from the experts.
1. We have provided software development and other IT related training to many major corporations in California since 2002.
2. Our educators have years of consulting and training experience; moreover, we require each trainer to have cross-discipline expertise i.e. be Java and .NET experts so that you get a broad understanding of how industry wide experts work and think.
Discover tips and tricks about Linux Unix programming
Get your questions answered by easy to follow, organized Linux Unix experts
Get up to speed with vital Linux Unix programming tools
Save on travel expenses by learning right from your desk or home office. Enroll in an online instructor led class. Nearly all of our classes are offered in this way.
Prepare to hit the ground running for a new job or a new position
See the big picture and have the instructor fill in the gaps
We teach with sophisticated learning tools and provide excellent supporting course material
Books and course material are provided in advance
Get a book of your choice from the HSG Store as a gift from us when you register for a class
Gain a lot of practical skills in a short amount of time
We teach what we know…software
We care…

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