Services. Dispatcher of management of services.

Services (Services) - it's user-mode processes, startup and operation for which the registration of the interactive user in the system is not required. And so, the vast majority of workers do not have a user interface. This is the only category of user applications that can run in this mode. Services are used, for example, to implement the servers. They can be executed as at system startup and thereafter. In this sense, the drivers, in fact, very similar to the service.

Dispatcher of management of services.

At the final stage of the system boot, before the appearance of the dialog user registration, runs SCM (\% SystemRoot% \ System32 \ Services.exe), which, looking through the registry key HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \, creates its own internal database (ServicesActive database or SCM database). Next SCM is created in the base all device drivers and services that are marked for automatic startup and loads them. Run the Administrative Tools > Services. We will see a list of installed services, To see a list of loaded drivers, run Administrative Tools > Computer Management and the left side System Tools > System Information > Software Environment > Drivers. The above mentioned registry key contains topics identified internal name of the driver or the service. Accordingly, each section contains configuration information about the driver or the service.

Subkey for the driver beep.sys

DisplayName - The so-called screen name, service applications displayed on the screen.

This parameter is optional. In his absence screen name is the name of sub-section.

ErrorControl - Determines how to respond to errors. For us, may be of interest of two values:SERVICE_ERROR_IGNORE (0) - The driver returned an error code is ignored. No warnings are not recorded;SERVICE_ERROR_NORMAL (1) - If the driver is in response to a command to run SCM, reports the error, warning and the error is logged in the system event log (system event log) indicating the cause of the failure. Actual debugging output driver causes - this will give the opportunity to learn exactly where in the code necessary to begin searching for an error.

System event log can be viewed using standard Windows 2000: (Administrative Tools> Event Viewer).

Driver beep does all the good work in the initialization phase (in the procedure DriverEntry), and returns an error code to be removed from the memory, because there's more for him to do nothing. Since the parameter ErrorControl for it is SERVICE_ERROR_IGNORE (0), then no entries in the event the system is not made.

48. Structure of the program of management of service.

The program in assembly language is a set of blocks of memory called memory segments. The program can consist of one or more segments of such units. Each segment comprises a first set of proposals, each of which occupies a single line of the program code.Proposals assembly are of four types:commands or instructions, which are symbolic equivalents of machine instructions.

During translation, assembly instructions are converted to the corresponding commands of the microprocessor instruction;

macros - provide a certain way sentence of the program, replaced during the broadcast of any other offer;

guidelines which are showing the compiler assembler to perform certain actions. We directives no analogues in the machine representation;

comment lines that contain any of the characters, including letters of the Russian alphabet. Comments are ignored by the translator.

Valid characters when writing programs are:

All letters: A-Z, a-z. In this case, upper case and lower case letters are considered equivalent;

the digits 0 through 9;

Signs?, @, $, _, &;

separators. [] () <> {} + / *%! '"? \ = # ^.

· Decimal numbers do not require for their identification specifying any additional characters, such as 25 or 139.

· In order to identify the source code of the program binary numbers needed after recording of ones and zeros that make them up, put the Latin "b", for example, 10010101b.

· Hexadecimal numbers are more conventions at his record:

First, they consist of digits 0 ... 9, upper and lower case letters of the alphabet a, b, c, d, e, f, or A, B, C, D, E, F.

Secondly, the translator may have difficulty recognizing hexadecimal numbers because they may consist entirely of numbers 0 ... 9 (eg 190845) and begin with the letters of the Latin alphabet (eg ef15). In order to "explain" the compiler that the token is not a decimal number or identifier, the programmer must allocate a special way hexadecimal number. To do this, at the end of a sequence of hexadecimal digits that make up a hexadecimal number, write the Latin letter "h". This is mandatory. If a hexadecimal number begins with the letter, before it is written leading zero: 0ef15h.

Almost every sentence contains a description of the object over which or through which an action is performed. These objects are called operands.

They can be defined as:

Operands - are objects (some values​​, registers or memory), which act on instructions or directives, or objects that define or clarify the effect of instructions or directives.

Date: 2015-01-29; view: 925