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Computer Programming
A category for questions about computer programming and programming languages.
10,506 Questions
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Define Task in embedded system?
Before we can explain what a "task" is in an embedded system it is important to understand that most embedded systems use a single microcontroller or microprocessor. The microcontroller (MCU) can do only one operation at a time but is fast enough to handle thousands of these operations per second (or much more, depending on the MCU). The application developer decomposes the application into a series of tasks (also known as threads or processes).
Each task is given control of system resources by the real-time operating system (or some other scheduler) for a period of time and then yields control to another task. These tasks must share the MCU with all other tasks so it is important that no single task dominates the system. The developer assigns a priority to each task. The scheduler (in the real-time operating system) gives control of the system to the highest priority task that is ready to run, preempting any lower priority task that is currently in control of the system.
In computer programming, a variable can be (among other things) an integer or a long integer.
An integer can be any whole number in the range of -32,768 to 32,767
A long integer can be any whole number in the range of -2,147,483,648 tp 2,147,483,647
I have never heard of an "integer" variable being called a "short integer" but it makes a kind of sense.
Note: The size of integer types is platform-dependent, but usually:
short: 16 bits
int: 32 bits (16 in archaic systems: MSDOS OS Windows16)
long: 32 bits (64 in unix64)
long long: 64 bits
Why far pointer is not there in Linux?
Pointer types are very specific to the compiler used and oftentimes subject to the target architecture. The concept of a near/far differentiation may not have any meaning on the memory model of your target. This has nothing to do with Linux or whatever OS you choose to use. More information should be provided with the documentation of your compiler.
What is the process for installing SAP software?
Administering an Oracle/SAP system, and maximizing the performance of its database, is a formidable job. You need to fully understand how both the SAP and Oracle systems work in isolation, and you need to know how they work together. In subsequent chapters of this book, I'll describe the specifics of that interaction. You'll learn how to use the special Oracle/SAP utilities, how to deal with the limitations of conventional Oracle functions, and how to place and reorganize files. Furthermore, after reading this book, you'll know more about monitoring databases during operation, tuning them, running backup and recovery, and performing special operations for systems that use parallel technologies or that support unusually large databases.
This chapter presents the fundamentals of the SAP architecture and describes how Oracle fits into the SAP runtime system. It also explains fundamental Oracle/SAP concepts -- the client/server model, special Oracle/SAP naming conventions, administrator roles, and basic administrative operations. First, though, let's take a step back and look at what SAP is.
Introduction to SAPThe SAP system is a collection of software that performs standard business functions for corporations. The system has become very popular because it provides a complete solution to standard business requirements such as manufacturing, accounting, financial management, and human resources. It incorporates the concepts of enterprise resource planning (ERP) and business process reengineering (BPR) into an integrated solution for business applications.SAP is a product developed and marketed by the German company SAP AG. SAP is a German acronym for "Systemanalyse und Programmentwicklung," which can be loosely translated into "Systems and Application Products." Founded in 1972 by IBM application developers, SAP AG originally developed application products for the European marketplace. For nearly two decades, the company grew slowly. Early versions of its software were mainframe-based and appealed particularly to very large European corporations. Within the United States, sales were mainly to the Fortune 500.
SAP's R/3 SystemDuring the 1990s, companies of all sizes began to embrace the concept of ERP systems and to gravitate toward prewritten business applications. With the introduction of its client/server SAP R/3 system in 1992, SAP AG, which already had a sizeable lead in the ERP market, unveiled a system that was attractive to medium- and small-sized companies as well as to the large companies already using SAP software. The SAP R/3 system runs on virtually any hardware/software platform and can use many different database management systems. One SAP system might be based on an IBM AS/400 running OS/400 using DB2; another might be based on a Sun Solaris (a dialect of Unix) using the Oracle RDBMS; still another might be based on an IBM PC running Windows NT using SQL Server. While SAP can be run with many different database products, nearly 85% of SAP customers now choose Oracle because of its dominance in the database marketplace. SAP software has become very popular in the U.S., and the company is now the world's leading application package vendor. SAP competes directly with Oracle Applications products and PeopleSoft products in the ERP marketplace.
The SAP R/3 code is written in an interpretive language called ABAP. (ABAP is a German acronym that, loosely translated, means "Advanced Business Application Programming.") ABAP is very similar to COBOL in its syntax. Use of the ABAP language allows SAP customers to extend the functionality of the base product, as described in the next section.
SAP Application ProductsThe SAP R/3 application offers end users the ability to run their entire business from a single application vendor. Some SAP customers choose to run their entire enterprise from SAP, while others run SAP only for specific business processes, such as manufacturing or finance. SAP is designed to allow customers to choose their own set of business functions, and it is sold in many configurations--both as specific business functions and as enterprise-wide solutions.
An SAP customer can choose whatever applications meet his site's specific business requirements. In addition, the customer is free to customize his SAP installation, adding new database entities as well as new functionality. For example, a company may use an inventory method that is nonstandard but essential to the company's efficiency; the basic SAP functionality can be modified to accommodate the specific requirements of that inventory method. The result of all of this flexibility is that virtually every SAP installation has its own specific configuration and set of functions. However, there are costs associated with customizing SAP. An organization that makes thousands of customizations to its SAP application may find itself spending millions of dollars to upgrade SAP: when SAP is upgraded, every customization must be identified in the ABAP code, and these changes must be reapplied to the upgraded SAP software, increasing the cost of the upgrade.
SAP products are distributed as applications with functional modules inside each application. Applications are generally focused on particular business functions. The modules within each application perform specific business tasks such as capital investment management, personnel administration, and quality management. The major applications are financials, human resources, and logistics, described briefly in the following sections.
In addition to basic business functions, SAP also offers products in the following areas (see http://www.sap.com/products/ for details):SAP Business Intelligence initiative
SAP Supply Chain Management initiative
SAP Customer Relationship Management initiative
SAP Electronic Commerce
SAP Human Resources
SAP Treasury
SAP Real Estate
SAP Environment, Health, & Safety
When an SAP application is purchased with Oracle, each of the modules is delivered with a complete Oracle schema consisting of thousands of tables and indexes. Because the end user may purchase one or more components of SAP, SAP delivers the definition for many more Oracle tables and indexes than will be used by the running application. It is not uncommon to see an SAP application where thousands of tables and indexes are allocated but never used by SAP.
SAP has also branched out from traditional online transaction processing (OLTP) products into data warehousing with its Business Information Warehouse (BIW) and Supply Chain Optimization, Planning, and Execution (SCOPE) products.
Financials applications
The SAP Financials applications contain all of the functionality needed for enterprise-wide financial management. The modules within the Financials applications include the following:Financial Accounting (FI)Provides a complete financial accounting solution, including income statements, balance sheets, journals, ledgers, and all areas of financial accounting.Enterprise Controlling (EC)Assists in controller tasks.Capital Investment Management (IM)Assists finance organizations in their capital investments and tracking.Controlling (CO)Assists the controller organization.Treasury (TR)Assists with transactions related to the U.S. Treasury.
Human Resources applications
The SAP Human Resources (HR) applications are designed to provide a fully functioning HR system. They include two primary modules:Personnel Administration (PA)Assists with all areas of personnel administration, including applicant tracking and personnel history.Personnel Development (PD)Assists with training and educational status of employees.
These systems handle all of the mundane HR tasks, such as personnel and payroll, and also a number of more esoteric HR functions, such as seminar and convention management.
Logistics applications
The SAP Logistics applications include SAP's most popular modules. Logistics was the first area of entry for SAP. This includes virtually every area of manufacturing, from the initial acquisition of raw materials to the delivery of finished goods. The modules in this area include the following products:Materials Management (MM)Manages raw materials, inventory, and all aspects of goods manufacturing.Production Planning (PP)Offers sophisticated tools for planning large production environments.General Logistics (LO)Manages logistics for companies that require large-scale deployment of goods and resources.Sales and Distribution (SD)Manages the inventory and distribution of finished goods.Plant Maintenance (PM)Manages the resources required for large manufacturing plants.Quality Management (QM)Captures and maintains quality control for manufacturing environments.Project System (PS)Assists with the scheduling of project tasks and interdependencies between tasks.
The SAP R/3 System ArchitectureAll SAP R/3 applications are delivered in a three-tier client/server architecture, shown in Figure 1-1.
Figure 1-1.The SAP three-tier client/server architectureFigure 1-2.The SAP Dialog instance configuration
The WP is the task that is charged with executing the application's tasks. As such, a WP consists of an ABAP language interpreter and processor, a task handler, and a means of connecting to the Oracle database. SAP defines several types of work processes, as follows:Dialog (DIA)Executes interactive dialogsBatch (BTC)Executes background tasksUpdate (UPD)Manages database updatesEnqueue (ENQ)Manages resource locksSpool (SPO)Manages data formatting and printing
The WPs can be viewed from a variety of places via SAPGUI, the SAP management tool. In SAPGUI, each screen has a name, and the SAPGUI screen called SM50 shows the currently executing WPs on a dialog instance (see Figure 1-3). SAPGUI has more than 100 screens, but in this book I'll focus on the major database screens. See Chapter 2, Oracle/SAP Utilities, for a discussion of SAPGUI and SAPDBA, the primary SAP utilities.
Figure 1-3.SAPGUI transaction SM50 displaying SAP work processes
The SAP system administrator, commonly called the BASIS administrator, controls the number of WPs that are defined to each application server. (See the "Oracle/SAP Administrators and Tasks" section later in this chapter.) In addition, the BASIS administrator can define "op modes" that control the number and type of WPs for each application server. For example, the BASIS administrator might define a day mode consisting of more dialog WPs for interactive sessions, and a night mode consisting of more batch WPs for the evening batch processes. These op modes are automatically switched by SAP according to the timetable specified by the BASIS administrator.
Oracle/SAP Naming ConventionsIn order to maintain control over a vast set of applications, SAP has devised a convention for naming common components. These conventions are more than suggestions; in many cases, deviation from the naming conventions may cause some management components of SAP (e.g., SAPDBA) to function improperly. Thus, it's very important that all SAP systems follow these naming conventions.One firm rule relates to the Oracle table and index names. Obviously, the SAP table structures and table names cannot be changed without changing the ABAP programs that access these tables, and SAP strongly urges customers not to alter the Oracle entities without the express consent of SAP AG. However, the Oracle administrator does have control over the naming of some Oracle entities (tablespaces and datafiles) and their placement within the filesystems and disk devices. The main areas of concern for the Oracle administrator are the Oracle SID name, the name and location of the Oracle initialization file, and the names of the Oracle tablespaces and datafiles; these objects are described in the following sections.
The Oracle SID in SAPSAP mandates that the Oracle SID (System IDentifier), specified in Unix and some other operating systems as ORACLE_SID, always begin with an uppercase "SA," followed by a single alphanumeric digit or a single uppercase alphabetic character. Thus, the SID may have the values SA0-SA9 or SAA-SAZ. These are the only allowable choices for Oracle database SIDs. Throughout this book, I've used the notation sapsid to refer to the Oracle SID established for your own database. The Oracle Initialization File (INIT.ORA) in SAPWithin an SAP system, the Oracle initialization file must exist with a specific name in a specific directory; if it does not, the SAPGUI and SAPDBA utilities will not work properly. Within both Oracle documentation and third-party books, the initialization file is ususally referred to as INIT.ORA, and I've followed that convention in this book. Note, however, that the actual name of this file in your system will be INITsapsid.ORA, where sapsid is the Oracle SID for your database (described in the previous section) and has the name you've specified for it. For example, if your Oracle SID is SA9, your initialization file will have the name INITSA9.ORA. In SAP systems, the intialization file must be located in the directory oracle//dbs; for example, oracle/SA9/dbs.In addition to the basic initialization file, SAP allows configuration or subinitialization files to be called from the INIT.ORA file. Most Oracle administrators find it more convenient to place all of the Oracle initialization parameters in a single file; however, sometimes it makes sense to segregate different types of parameters into several files. For example, if your site is configured differently for transaction processing (during the day) and for batch processing (at night), you might include common initialization parameters in a single configuration (CONFIG.ORA) file but have separate INIT.ORA files for day and night processing. You'd restart with the appropriate INIT.ORA file for each time period. (This approach should not be confused with BASIS op modes.)
Within the INIT.ORA file, you must follow the SAP conventions for parameters summarized in Table 1-1.
Table 1-1:SAP Conventions for the INIT.ORA FileFigure 1-4.Standard SAP tablespaces
SAP has segregated the Oracle tables into tablespaces according to their functions. As shown in Figure 1-4, each tablespace can be classified as a transaction tablespace, a BASIS tablespace, or an SAP system tablespace. Note that the SAP application has a system tablespace (called PSAPDICTD), just as the Oracle database has a system tablespace. The following sections describe these tablespaces. SAP folks disregard the leading PSAP in each tablespace and the ending "D" or "I" in each tablespace name. Hence, the PSAPSTABD tablespace is commonly referred to as STAB.
Transaction tablespaces
Transaction tablespaces hold the application data for individual transactions. These transaction tablespaces include the BTAB, STAB, and USER1 tablespaces:BTABHolds the SAP transaction tables. These tables constitute the heart of SAP, and the Oracle administrator may choose to migrate the largest and most active tables into other tablespaces for improved data management.STABHolds the SAP master data and transparent tables. These are normally the master reference tables for the SAP application holding commonly referenced application information.USER1Commonly defined to hold user customization tables that are not defined with the SAP software.
In an operational SAP database, these tablespaces will experience the highest read-write activity and will grow very large as your end users load SAP with their business data. Thus, you'll need to monitor these tablespaces very closely, since they may fill and cause the entire SAP application to stop. Many Oracle/SAP administrators run scripts to identify the largest and most active tables in these tablespaces and move these tables into separate tablespaces. These separate tablespaces are then segregated by disk for better overall I/O management. Oracle administrators sometimes use file striping for these tablespaces to balance the load across many disk devices, and thereby improve throughput. I'll describe SAP tablespace monitoring in some detail in Chapter 4, SAP Database Monitoring.
BASIS tablespaces
The BASIS tablespaces include BTABD, STABD, DICT, LOAD, PROT, and SOURCE. SAP uses these Oracle tablespaces to store data that is used to perform basic SAP system functions. For example:PROTHolds the output from ABAP reports while they are waiting to be printed, and contains spool, converter, and log tables.SOURCE and LOADContain the ABAP source code for reports and screens. In an SAP system, remember that ABAP is run in an interpretive mode, and the source code is gathered from these tablespaces at runtime for interpreting.DICTContains the ABAP data dictionary, and consists of SAP metadata; in this sense, the DICT tablespace is very similar to the traditional Oracle SYSTEM tablespace.
System tablespaces
The most important SAP system tablespaces are POOL, CLU, and DOCU:POOLUsed to store the SAP system pool tables. These are similar to the master data tables found in the STAB (transaction) tablespaces, but SAP considers them too small to require their own Oracle tables. The items from the POOL tablespaces are generally buffered and loaded into the memory of the dialog instance, so POOL is not heavily accessed except at SAP startup time.CLUContains SAP cluster tables. Unlike Oracle clusters, SAP cluster tables are stored into Oracle tables with LONG RAW datatypes. The data within the LONG RAW columns are used by SAP as subtables, and each row within an SAP cluster table may contain data that is completely unrelated to the next row in the table. These pseudo-tables present a challenge to the Oracle administrator, especially when they must be reorganized, because you can't use Oracle's CREATE TABLE AS SELECT command with tables that contain LONG RAW columns. Consequently, reorganizations of the CLU tables must be performed with Oracle's slower Export/Import utilities. I'll discuss this topic in Chapter 5, Table, Tablespace, and Index Reorganization.DOCUContains the document tables, including the sapscript and sapfind tables. This is a relatively small tablespace with fewer than 30 tables.
Oracle Files in SAPIn a typical Oracle configuration, you can map an Oracle tablespace to a single datafile or to many datafiles. Because of the large size of many SAP installations, an Oracle/SAP tablespace generally maps to many datafiles. In a production SAP environment, many of these tables will never be used, while other tables will grow very rapidly. Thus, in general, you should identify and segregate the highly active tables into separate tablespaces. Chapter 4 includes a script you can use to identify the SAP tables that are growing.
SAP is quite strict about the names for its default tablespaces, so you cannot change these names, but you can add new tablespaces. When you segregate SAP tables into a separate tablespace, however, you can name that tablespace anything you like. Although SAP gives you complete freedom in tablespace naming, SAP AG suggests that when a new tablespace contains a single table, the tablespace name be a permutation of the table name. For example, the table named VBAP could be moved into a tablespace with any of the following names: PSAPVBAPD, VBAPD, or VBAP. An SAP purist would preface the tablespace name with PSAP and end the tablespace with the letter "D." This is helpful in order to be consistent with the other SAP naming conventions, and it can also be helpful when using SAPGUI to view tablespace information.
Oracle system files
While many standard Oracle configurations generally follow Oracle's Optimal Flexible Architecture (OFA) standard, SAP has changed this standard somewhat, in an effort to create a "flat" file hierarchy (see Figure 1-5).
Figure 1-5.The Oracle/SAP file architecture
Note that $ORACLE_HOME is set to the same value as /oracle/, and all of the Oracle database software is located directly beneath this directory. For example, the Oracle executables are always located in /oracle//bin.
Oracle datafiles
Within SAP, Oracle database files are named somewhat differently from the way they're named in traditional Oracle databases. The default SAP installation uses datafile names in which the prefix matches the tablespace name. For the filename suffix, rather than using a dbf suffix, SAP requires that datafiles contain the datan suffix. In this way, the Oracle datafile called psappooli.data3, for example, will be instantly recognizable as the third datafile for the POOL data indexes.
Oracle indexes
SAP also follows a standard for index naming. All Oracle index names default to eight characters in length; they always begin with the table name, end with a number, and use between one and three underscore characters in between. All indexes that end with a zero represent the primary key indexes for the table, and all nonzero numbers represent secondary indexes. For example, you will be able to tell that VBEP_ _ _0 is the primary key index for the VBEP table, and that VLPMA_ _1 is the secondary index for the VLPMA table. To properly display indexes within SAPGUI, all new SAP indexes should begin with the table name and end with a unique numeric character. Also, it is important that the index names be eight characters long, using a variable number of underscore ( _ ) characters.
SAP Filesystems on UnixIn addition to the required Oracle filesystems, some SAP-specific filesystems are found on most of the SAP application servers. These filesystems are used to hold certain Unix files that are required for SAP to function in the Unix environment. These include the SAP executable programs, SAP configuration files, and other SAP system-related datafiles, as follows:/usr/sap/transThis directory contains the common transport directory, .sapconf, as well as other SAP and Oracle configuration files. For distributed Oracle systems, this directory may also contain the master tnsnames.ora and sqlnet.ora files./sapmnt/This directory stores system-wide files for SAP, including executables, global files, and profiles./usr/sap/This directory stores instance-specific files for each SAP dialog instance.
The Oracle Database Layer of SAPAs you know, SAP is designed to work with many database management systems; interfaces are available for Oracle, DB2, Informix, and several other database products. Since SAP is database-independent, the SAP architecture requires the database to be defined as a part of the initial SAP installation. Once defined, the SAP programs (ABAP programs) will generate SQL that is compliant with the target database product.Native Oracle SQL is generated by the ABAP program at runtime, and the SQL is then passed to Oracle for execution. The dynamic nature of ABAP SQL greatly increases its flexibility, but it makes it very difficult for the Oracle administrator to provide SQL tuning for Oracle. Because the SQL is generated from the ABAP at runtime, there is no way to change the execution
The three layers are:Presentation layerThe PC-based GUI interface that is used by the end-user community.Application layerThe SAP application servers that service requests for data and manage the interface to the presentation layer.Database layerThe actual DBMS that communicates with the application servers to fulfill their requests for data.
A piece of "middleware" called BASIS links the application to the database and the operating system. BASIS is most commonly associated with the GUI interface to SAP (called SAPGUI), and the BASIS Administrator is an SAP professional who is responsible for configuring the SAP environment, including the GUI screens and the SAP application servers.
SAP end users log into their PCs using SAPGUI, and are connected to a specific application server. This application server has pre-established connections with the Oracle database, and it services all requests for data. As I mentioned earlier, the access language for Oracle data is SAP ABAP. ABAP generates Oracle SQL (Structured Query Language), which is then used to service the end user's request for data. The communication between the application servers and the database, and between the client and the application servers, is TCP/IP.
While SAP is available for many different hardware platforms and operating systems, the majority of SAP systems use Unix-based servers for hosting SAP and the Oracle database. For this reason, as mentioned in the Preface, this book assumes the use of Unix in most examples.
The application server
While SAP uses the generic term application server to define a computer that receives connections from SAP clients, the actual connections are managed by SAP dialog servers.
A dialog instance is a software program that is running the SAP kernel (similar to an Oracle instance), and it is the job of the dialog instance to execute the ABAP programs and manage the requests for data and services. While there is generally a one-to-one mapping between an application server and a dialog instance, it is possible to have more than one dialog instance on an application server.
The central instance
The central instance is a concept that is unique to SAP. The central instance is a combination of hardware and software. It contains a physical server (the application server) and numerous software components, including a message server, a database gateway (a pre-established connection between SAP and Oracle--or another database), and various update, enqueue, dialog, and spool facility software. In most generic SAP architectures, there are numerous application servers but only a single central instance. However, in addition to managing the SAP interfaces, the central instance can also serve as an application server.
Bear in mind that SAP is very flexible, and there are many different ways to configure an SAP architecture to meet your business needs. However, most companies that implement SAP wisely choose to alter their business practices to accommodate SAP. By avoiding customization of its SAP application, a company can more easily upgrade its SAP software.TIP: In 1998 SAP AG announced that the company is planning a four-tiered client/server architecture that will isolate the database from the SAP applications. Under the four-tiered architecture, the database will be insulated from SAP by the use of an active database cache called liveCache. This expanded memory cache will act as a separate layer, further insulating the Oracle database from the SAP application and allowing for the real-time manipulation of database objects.
Work processes
Any computer is capable of running one or more application servers. The main purpose of a dialog instance is to intercept requests for work from the SAP clients and to execute ABAP programs to service the requests for data. In addition, a dialog instance contains a dispatcher task and a set of work processes (WPs). The WPs are Unix tasks that can easily be identified by logging on to the Unix server and entering the following command:PS -ef|grep dw
All SAP WPs contain the string "dw" (an acronym for Dialog Work) in their process names. The dispatcher on an SAP dialog receives requests from the SAP users (see Figure 1-2). In cases where a computer is running more than one dialog instance, there is one dispatcher for each dialog instance.INIT.ORA ParameterFilesystem DestinationUSER_DUMP_DEST
/oracle//saptrace/usertrace
LOG_ARCHIVE_DEST
/oracle//saparch/SAPSID_
BACKGROUND_DUMP_DEST
/oracle//saptrace/background
AUDIT_FILE_DEST
/oracle//rdbms/audit
CONTROL_FILES
/oracle//sapdata-nn/cntrl1.data1
Oracle Tablespaces in SAPIn an SAP system, Oracle tablespace names always begin with the string "PSAP" and end with a "D" (data tablespace) or an "I" (index tablespace). Some of the common SAP tablespaces are PSAPCLUD, PSAPLOADD, and PSAPDICD.
A standard SAP system contains only a handful of tablespaces. These tablespaces are designed to contain all of the SAP tables, and are defined as a part of the default SAP installation. Figure 1-4 shows the sample tablespace descriptions for an SAP installation. Within an Oracle/SAP tablespace, many of the tablespaces will remain small--for example, the metadata information in the DICT tablespace.
What do you mean by Microsoft Excel?
Microsoft is a brand like Addidas or Prada. Excel is a programme that you use for producing spreadsheets.
How can you use utility programs and shell prompt to create your own applications?
You'll have to learn some shell scripting. for example, in the terminal :
$vi hello.sh
will create a file hello.sh for you to write into.......sh extension is needed
suppose you typed in
"echo hello world"
and saved the file [press escape and then shift+z+z]
then when u type in ./hello.sh in the terminal, the following message will be displayed :
hello world
That's how it starts!!!
All you need!
A clarification on the above answer: the extension .sh is not required, since Unix does not need extensions of any kind. It is, however, helpful to include it for documentation purposes (so you know what the intent of the file is).
Secondly, the shell file created above will not execute unless the permissions are set appropriately. They should have 'read' and 'execute' permission to run on the command line as described above.
How you run C plus plus compiler in windows 2007?
There is no operating system known as "Windows 2007". The only Microsoft operating system released in 2007 was Microsoft Windows Server 2008. Microsoft Windows Vista was released earlier in 2006 and has since been superseded by Microsoft Windows 7 (released in 2009), Microsoft Windows Server 2012, Windows 8 (2012), Microsoft Windows Server 2012 R2 and now Microsoft Windows 8.1 (2013).
As to how you run a C++ compiler on Microsoft Windows (regardless of the version), you first have to download or buy a compiler as well as a linker and a resource compiler. However, compilers and linkers are not generally available separately, they usually come as part of an Integrated Development Environment (IDE), which includes project management facilities and code editors. Your IDE documentation will tell you how to run the built in compiler from the command line, however in an IDE this is seldom necessary as all compilation and linking can be achieved from within the IDE itself.
Why is cross-platform connectivity important to many computer users?
Users want to communicate with one another, without being restricted by incompatibility between different types of computers.
What are the programming cycle?
Steps for Programming Cycle
- try to understand and analyze the problem.
- write the algorithm or draw the flow chart for the problem.
- create the source file using editor and the code according to the flow chart or algorithm.
- compile the program using the system software and the object file is created.
- step 4 is repeated till the source program contains no compilation errors, then step 6.
- link the necessary library files needed for the compilation of the object file.
- load the file for execution.
Steps 6 and 7 are a part of the execution process.
- execute the program using the run option.
Dry run technique in c language?
dry run is nothing but manual compilation of code with an example for written steps to check whether the code for particular problem is solving or not.....if it not happens change code accordingly...........
Yes. In your e-mail client's message rules, simply select the "run a script" action to send an alert message to your other account. You'll have to write the script yourself but your e-mail client needs to be running 24/7 for this to work. To achieve the same thing on an e-mail server you'd need permission from the server's administrator, but such permission is unlikely to be granted.
How do you detect overflow when adding two numbers in 2s complement form?
You can detect overflow if the result turns out to be negative (which is the same as checking to see if the sign bit is 1).
For example if you tried to add 5 and 6 in to 4-bit 2s complement, you would get
0101 + 0110 = 1011, which is a negative number since the sign bit (the 1 on the left) is a 1. This is an overflow.
What does Time Machine on a Mac actually do?
Time Machine is a piece of software included with the Mac operating system, Mac OS X 10.5 and higher (Leopard and higher). Time Machine functions by making a complete, bootable backup of the entire internal hard drive on a Mac onto an external hard drive of your choice (though it must be formatted specifically for the Mac, using the HFS+ formatting scheme). It makes backups of files every hour, every day, every week, and every month, until space on the chosen external drive that is used as the Time Machine is full.
From that point on, the software will delete the oldest backups, and add files or changes as they are added to the internal hard drive. For example, if you make a complete backup on October 1, any changes you make after that date will be added as "incremental" backups. If your October 1 backup did not fill up your entire external hard drive, then any changes would be added on October 2.
Time Machine works automatically once you have set it up, and once you have the external hard drive plugged in. It is recommended to make your backups as often as possible, in order to have the most recent files available to you in your backup, should you require them.
In the latest version of the Mac operating system, Mac OS X 10.7.1, Lion, you can also make Time Machine backups to an additional internal hard drive. However, if your entire computer is destroyed or otherwise damaged, your backup would also be lost, which is why it is often recommended to have an external, if not off-site (and/or online) backup as well.
Time Machine can also be configured to backup other external hard drives (such as USB flash drives) or NOT backup specific folders within your internal hard drive.
Computers cannot process anything but binary numbers. Even character strings are just arrays of whole numbers (character codes), so there is absolutely no difference in the processing speed of an array of integers and an array of characters. While the type of operations you will perform on strings are quite a bit different to the arithmetical operations you will perform with numeric data, as far as the computer is concerned there is no difference at all. It's all numeric so there's no difference in terms of processing speed.
There is, however, a key difference when it comes to displaying the data in a human-readable form. Displaying a character is simply a matter of emitting the character code which maps directly to a corresponding glyph, such as a bitmap. But converting a binary value to a decimal value requires that each decimal digit be determined before it can be mapped to its corresponding raster. This clearly requires additional processing.
The same can also be said of floating point values which require dedicated floating point co-processors to ease the burden. Integer arithmetic is simple by comparison.
So, while there is little difference in terms of actual processing, there are differences when it comes to displaying the results. In that sense alone, character data can be dealt with more efficiently than numeric data.
However, if character data is used to represent numeric data, such as the string "123.45", then numeric data is far more efficient because the string must be converted to and from an actual numeric value, whereas the numeric value does not.
How do you set data rate in wt12?
No idea what you are asking. What is "wt12"?
Please clarify and ask the question again. :-)
Whati is Constructor overloading?
Constructor overloading is the feature by which we declare multiple constructors for a single class. Ex: let us say we want to create multiple constructor for a class Test
Public class Test {
Public Test() {
//code
}
Public Test(int vals) {
//code
}
Public Test(String val) {
//code
}
}
What are the disadvantages of Component Object Model?
Previously, before .NET, this used to be a major issue. "DLL Hell" refers to the set of problems caused when multiple applications attempt to share a common component like a dynamic link library (DLL) or a Component Object Model (COM) class. In the most typical case, one application will install a new version of the shared component that is not backward compatible with the version already on the machine. Although the application that has just been installed works well, existing applications that depended on a previous version of the shared component might no longer work. In some cases, the cause of the problem is even more subtle. In many cases there is a significant delay before a user discovers that an application has stopped working. As a result, it is often difficult to remember when a change was made to the machine that could have affected the application. A user may remember installing something a week ago, but there is no obvious correlation between that installation and the behavior they are now seeing. The reason for these issues is that version information about the different components of an application aren't recorded or enforced by the system. Also, changes made to the system on behalf of one application will typically affect all applications on the machine.
One reason why it was hard to build an isolated application was the run-time environment typically allowed the installation of only a single version of a component or an application. This restriction means that component authors must write their code in a way that remains backward compatible, otherwise they risk breaking existing applications when they install a new component. In practice, writing code that is forever backward compatible is extremely difficult, if not impossible. Also components were shared because disk space and memory was expensive. In the past few years, hard disk and memory prices have dropped dramatically, and disk space is no longer a premium. But as applications have increased in size and in modularity not so long ago many applications were entirely self-contained in a single .exe file - the DLL sharing issue has not been addressed, and the problem has grown over time.
Sagar Kulkarni
Why do you need translator according to compiler design?
the PC or computer ONLY UNDERSTAND 0 and 1 (Binary Code) which is a switch between on and off in electric current. if we do not use translators or compilers we will have a hard time trying to program the PC to do something so we use something more understandable(command syntax) to "tell" the PC what to do
Singly list program using data structures in C?
//Singly linked list:
#include<stdio.h>
#include<stdlib.h>
typedef struct list
{
int data;
struct list *next;
}node;
node *head = NULL;
node* create_node()
{
node *new1 =malloc(sizeof(node));
printf("\nEnter data:");
scanf("%d",&new1->data);
new1->next = NULL;
return(new1);
}
void insert_beg()
{
node *new1;
if(head 1)
insert_beg();
else
insert_after();
break;
case 3: search();
break;
case 4: display();
break;
case 5: printf("\nEnter the data to be found");
scanf("%d",&x);
find_prev(x);
break;
case 6: deletion();
break;
case 7: exit(0);
}
printf("\n\n");
}while(ch != 7);
getchar();
return 0;
}
How do you use float values in Linux?
This is such an incredibly vague question. How do you want to use them? In C Programming? perl? python? at the command-line? Please clarify.
NEXI is the acronym for the company Nippon Export and Investment Insurance. It is an insurance company that specializes in marine vehicles.
How do you record time in ROBOTC?
i have been looking to do this for awhile for a project, using the timer to start when i press the limit switch and for the time to stop when it reaches the sonar senor. I don't think its possible. But if u figure out a way let me.
