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In Data-processing, a Batch processing ( batch processing in English) is an automatic sequence of orders without intervention of an operator. The release of these treatments can thus be automated, for example thanks to the program Cron in a system Unix. The batch treatments are especially used for automated jobs, in particular for the management of the accounts on the information technology infrastructure of a company, of a university… The work launched in batch uses only the cycles processor not used by interactive work. The batchs thus have always a priority of execution lower than the interactives but on the other hand an execution time ( time slice ) higher than the interactives in way of remaining about it in main memory more the possible for a long time. Why the time slice is more generous for a batch than for an interactive work? Because at the time of a reading order of the database, the system gives the responsability in the buffer several slots in order to make the least possible of access disc, knowing that an access disc immediately causes a purging on disc of the batch which will have to wait to return in memory to continue to be carried out.

The second generation of computers was exploited exclusively in the form of batch processing, progress on the use in vacations of those of the first generation. The concept of Operating system became essential then. The computers were supplied with entry by instructions encodées on perforated cards and provided the output data on Imprimante S (example: the system FMS).

The interactive terminals in Ligne of order were spread only about the middle of the Années 1960, when that the cost of the machine time became sufficiently accessible - and thus touched a vaster number of potential users - thanks to the third generation of computers.

A true batch treatment includes/understands codes of condition making it possible to connect the treatments like a true program (if… then… if not…). A program batch does not have need to be carried out to obtain an answer of the user. For example, if you ask for the calculation of the pay of the month, the program will read various tables and will treat the recordings to generate the pay slips and to update accountancy, to generate the file of the transfers for the bank and to print the bulletins. It is seen well that there is no dialog with the user, the program is carried out into autonomous. the batch processings are especially launched nights by the operators system according to established planning or by a robot under monitoring of only one operator. It should be noted that this concept of batch processings exists really only on the IBM environments (mainframe and AS/400) and at all on Windows, and Unix.

By extension, a file batch is, under the Operating system Windows, a file (or script ) containing a series of instructions DOS. These files, when they are launched, carry out the orders contained in the file.

The word batch then indicates wrongly an anonymous language, sometimes called Langage batch or Langage DOS, and which is interpreted by achievable the Cmd.exe and Command.com, less powerful than scripts using the shells Unix like Bash or Ksh, themselves less powerful than those of the Mainframe S. Enough editor batch celebrates names PowerBatch.

Software specialized in the management of the batch processings exists, for example:

  • Autosys, of the continuation Unicenter (System Managemement) at Computer Associates.

  • $Universe of Orsyp
  • TWS, of the continuation Tivoli at IBM

The programs of batch processing are opposed to the interactive, or compromise programs. It should be noted that the compromise one as CICS on the mainframes of IBM is anything else only one batch treatment which by the means of the pooling in turn gives the hand to the terminal whose bit is " on" in a table, i.e. that the program with all its data is brought back disc in main memory, carries out the transaction and is immediately purged again on disc.

It should be noted that the batch is slower all the same than the other languages because it is not compilable and thus asks, at the object time, an interpretation of its orders by Cmd.exe and Command.com, which sends then calculations corresponding to the orders to the processor. The other languages sends calculations directly, they are thus faster. One of the assets of the batch is its lightness: it is similar to the contents of a .txt file because the orders are in lines and without too many options.

But attention: a file batch can contain viral orders which, with the order PIPE, do not require a confirmation. A file batch can easily format a disc or remove a file. Little antivirus detects threats in the files batch. By precaution, you can open with your block-note a file doubtful .bat before launching it.

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