Software and hardware diagnostic tools. Description of computer diagnostic steps
The PC operating system includes four interconnected levels of interaction between the application program and hardware:
1) hardware (Hardware). This is all electronic equipment, cable management, electromechanical units and computer devices;
2) -hardware and software (Firmware). This - ROM programs BIOS on SB and expansion cards, firmware, system drivers, and so on.;
3) DOS (DOS-Software). This is system software system tools, user and application program interface, data flow control, interrupt handling, maintenance of input/output systems, scheduling of tasks, resources, etc.;
4) application programs (Software). These are user programs that solve specific problems (user tasks): calculations, database maintenance, management, design packages, text editors and so on.
The relationship between the levels of interaction between software and hardware of a personal computer can be represented as the following diagram:
Fig.58. Levels of interaction between software and hardware
For an application program (Software) to work, a dispatcher is needed that launches the program, provides it with computing resources (CPU, DRAM, disks, console, control unit, etc.) and processes emergency situations problems that arise during the operation of Soft Ware. This is the task operating system, in the diagram - DOS-Ware.
DOS provides an interface to application programs for convenient standard access to peripheral devices and, in part, to the user - for preparation, optimization and other functions current operation application programs and peripheral devices (formatting, copying, collating, deleting files and much more).
For DOS operation means of access to hardware resources are needed - drivers, interrupt handlers, controllers for the performance of the aircraft (this is Firmware, BIOS), specialized in this device and even his type. These tools, when the machine is turned off, are usually stored in ROM on the SB and on the disk controllers, monitor, etc., but most of the special external drivers are stored on disks. However, all Firm Ware is rewritten into the RAM of DOS itself after it is loaded. In RAM they are all resident until the next OS reboot. All physical computer hardware that performs logical transformations is designed to perform DOS functions. mathematical operations, control, synchronization, etc. (in the diagram this is Hard Ware).
In personal computers, when working in MS DOS, additional service tools are often used that provide the user with more user-friendly interface, than DOS itself offers, they are usually called DOS shells. These are NC (Norton Commander), DN (DOS Navigator), VC (Volkov Commander), and finally, Windows early versions. These tools in the presented diagram do not occupy a separate level, but are, as it were, part of DOS, oriented not towards Soft, but directly towards the user.
A special place in the scheme of interactions between Soft Ware and Hard Ware is occupied by optional, but very attractive service software - resident TSR programs (TSR - Terminate and Stay Resident - which remain resident in RAM at the end of work). They are able to perform big number functions not supported by DOS, such as Russification of the keyboard, display, disk caching, data compression on disks and much more. These tools are not allocated to a separate level, but, according to the logic of the relationship between the tools, they should be located between DOS Ware and Firm Ware, since they usually monitor and intercept DOS calls to drivers, performing their own functions, and, if necessary, independently call the necessary system and external drivers.
Operation of test programs
Testing in Windows environment, is difficult due to the specific features of this operating system. The developers of Windows OS set themselves the task of creating an intelligent operating system that could largely replace the user, equipping the program with many self-tuning and self-regulation functions. But this task turned out to be so complex that the program lives as if on its own during operation, creating many temporary files, private settings and control functions application programs and peripherals, the needs for which turn out to be unlikely, but which extremely complicate the operation of the OS itself.
The most well-known test programs in the Windows environment - Sandra-2000, AIDA-32, PC Wizard, BurnInTest - are designed to solve problems of an almost exclusively evaluative nature.
AIDA-32 will help you understand in detail the configuration of your computer hardware. Its interface is organized in Explorer style, so for many users it will be a familiar environment. Unlike Sandra, AIDA-32 provides quite detailed information about installed modules memory and hard drives. For each memory module separately, you can view and technical information, albeit incomplete, with SPD. SPD is an IC non-volatile memory, installed in each memory module, starting from PC 100. The manufacturer writes all the characteristics of this module into this memory. For hard drives, in addition to the name of its manufacturer with its URL, the technical characteristics of the drive are displayed, as well as the S.M.A.R.T. section. (Self-Monitoring, Alerting and Reporting Technology - drive self-diagnosis system). It is the attributes of S.M.A.R.T. can provide information about the current state of production hard drive. Among the performance tests in AIDA-32 there are only tests of system memory read and write speeds.
PC Wizard is a powerful information utility that, in addition to detailed information about the system, provides the ability to carry out a number of simple tests computer component In particular, performance tests for the microprocessor, video subsystem, speed tests for memory of all levels, including summary, and tests separately for each logical drive HDD. The tests are completed in a few minutes, but the nature of such testing raises doubts about its reliability.
WINCheckit. To diagnose a computer in a Windows environment, you can use the well-proven WINCheckit 6.5 program from Touchstone Software. Its QuickCheckit function performs quick diagnostics of all computer devices.
When a fault is detected, the WINCheckit diagnostic program runs in wizard style and offers possible ways solutions to the detected problem.
In addition to a comprehensive set of detailed diagnostic programs and status reports, WINCheckit provides links to important built-in Windows tools, ranging from the well-known Scandisk and Defrag programs to the little-known Automatic Scip Driver utility.
Sandra-2000 component does not perform in-depth diagnostic modes, but it measures and stores in the protocol all characteristics of the speed and performance of all components of the alarm system, with detailed indication of operating modes, combinations and results comparative characteristics performance according to the different testing modes used.
As an information complex, Sandra has no equal today. Its range includes about 60 information modules, each of which can contain not one, but several tests. All tests in Sandra are divided into informational and comparative. Information tests provide all the information about the system and its components, and comparative ones run through many different operating modes, comparing the speed characteristics of all components of the APS with the parameters of reference components from their database. Both tests give a lot of useful tips on the settings and configuration of the APS and information about errors found during testing or unsupported functions.
An important stage in computer repair is its diagnostics. After all, before making a correct diagnosis, it is necessary to conduct an examination. And this should be done by qualified specialists, for whom providing computer help is a profiling service.
Fault determination consists of the following steps:
1. Primary diagnosis.
This type of computer performance assessment is carried out at the customer’s home. Primary diagnosis cannot be complete and is only suitable in some cases. This mainly includes an external inspection of the computer and its components.
2. Hardware diagnostics.
This stage is aimed at identifying damaged computer parts. System malfunctions may occur if a defective component is installed on the equipment. In addition, incorrect operation may be caused by worn parts. Another option that affects operation is overheating.
3. Software diagnostics.
At this stage, errors in the operation of the software are identified. The stability of the system is assessed. The computer operating system comes under close scrutiny, with the causes of the software failure analyzed.
4. Full diagnostics.
Based on the results of all types of diagnostics, the service engineer makes a verdict - the cause of the breakdown. After agreeing with the customer on the cost of repairs, the necessary computer assistance is provided.
If you have any problems with your computer, do not try to solve the issue yourself. Qualified diagnostics and professional repair Can only be performed by an experienced specialist.
Primary diagnosis
A complex electronic computing device, which is a computer, is based on a mass of microcircuits and printed circuit boards. It follows that computer repairs by “amateurs” can only be carried out in limited number cases. Even standard repair work requires theoretical and practical knowledge, as well as extensive experience. Before starting to complete the order, the craftsmen carry out initial, and in difficult cases, hardware and software diagnostics.
Primary diagnostics of a computer consists of the following steps:
1. Superficial inspection of the software part of the equipment.
Superficial software diagnostics aims to check the functionality of the operating system and the correct functioning of programs. It is carried out at the customer’s home by a service engineer, without the use of diagnostic equipment.
2. Superficial inspection of the hardware of the equipment.
This is a visual check of the computer configuration and assessment:
Type of disks;
The amount of memory and the possibilities of its use;
Performance computer devices(primarily hard drives).
Using a superficial inspection, you can identify a number of simple equipment malfunctions.
Hardware diagnostics
The first step in computer maintenance and repair work is diagnostics. As practice shows, most malfunctions and equipment failures are caused by neglect of regular prevention and diagnostics.
The purpose of diagnostic work is:
Troubleshooting computer equipment;
Finding out their character.
Hardware diagnostics are aimed at identifying mechanical (even externally invisible) damage to computer components.
Computer hardware diagnostics includes checking temperature regime computer components and stability of operation:
Central processor;
Random access memory;
Hard drive;
Video adapter;
Chipset.
After this type of diagnosis, the client receives:
Report on the status of computer hardware;
Preliminary price calculation for troubleshooting work;
Modernization proposals.
Timely computer hardware diagnostics can significantly reduce system failures. If hidden problems are not identified at an early stage, your technique can be completely paralyzed at any time.
If a service engineer discovers damage to your computer components, replacement of parts and repairs will be required to restore its functionality.
Hardware diagnostics measures will allow you to carry out the necessary repair work in a timely manner, increase the performance of the equipment, and increase its performance. This is exactly the case when timely actions will prevent serious problems.
Software diagnostics of a computer is the detection of a defect and the causes of its occurrence. Wherein:
The operating system is reviewed taking into account the stability of the computer equipment;
The load resistance of individual components and the computer as a whole is checked;
Performance testing motherboard using special modules.
An amateurish approach to this process is fraught with a number of dangers. For example, if a motherboard malfunction is detected, the user replaces it without thinking about the causes of the failure.
Computer diagnostics program level will be required if:
1. The equipment does not turn on.
2. It turns off on its own.
3. Computer freezes.
4. Reboots for no reason.
5. Works slowly.
Software diagnostics of computer equipment includes:
1. Superficial inspection of the software part of the equipment.
2. Computer software testing, which includes:
Check file system for errors to occur;
Checking the operating system registry and its status;
Checking for critical OS updates.
Full diagnostics
Diagnosing a computer or determining the reasons for its poor performance should be carried out by qualified specialists. As practice shows, only professionals can eliminate a number of typical problems in the operation of computer technology.
Using a complete computer diagnostic, you can identify problems and identify opportunities for upgrading equipment.
This type of diagnostic work is performed only by experienced service engineers using specialized equipment and includes several stages:
1. Superficial inspection by a master of the software part of computer equipment.
2. Testing computer software using special utilities.
3. Superficial inspection of the hardware by a technician.
4. Testing additional components hardware device computer.
5. Testing the main components of a computer hardware device.
A complete PC diagnostic includes testing activities:
Software and operating system;
Motherboard;
Processor;
Hard drive;
Memory slots;
Information reading devices (floppy disks, drives, card readers);
TV tuners, network and Wi-Fi equipment, modems;
Video cards;
Circuits, unit and power controller;
Monitor.
All personal computer owners should remember: full diagnostics It should be carried out regularly, without waiting for the equipment to fail. In this case, your PC will serve you for a long time, and there will be no need for computer repair or replacement of components.
Technical diagnostics and control tools (TDK) are the main part of the TDS; they determine the operational and technical characteristics of these systems and provide all the necessary information to consumers about the technical condition of the diagnosed RES. In diagnostics, they play the role of terminal devices, being sources of information for the consumer and at the same time a receiver and processing device for diagnostic information. SDK belongs to a wide class of information-measuring systems (IMS), acts as terminal devices SDK and IMS, with their parameters, determine all output parameters of the system. If the diagnostic object allows for a certain depth of search for the location of the failure, and the SRDK is not adapted for this, then this operation cannot be carried out at the required level.
Technical diagnostic and control tools.
Thus, the main requirement for the SDK is the need to ensure that the capabilities and parameters of the SDK correspond to the capabilities and parameters of the diagnostic object. In addition, modern information measuring systems for monitoring and diagnosing RES are complex radio-mechanical systems that characterize a set of functional use parameters (FU), technical and operational parameters. From this point of view, SDKs can be considered as objects of diagnostics and objects of metrological support.
Being an integral part of the STD, SRDK determine the control and suitability of the diagnostic object, which is a property of the product that characterizes its suitability for diagnostics and control by specified means. Consequently, when analyzing in STD for any complex RES, the SrDC must either be specified in advance or designed together with the diagnostic object.
Rice. 6. Classification of SrDC.
Signs: 1 – by the nature of unique tasks; 2 – by communication method and location; 3 – by purpose and type of information processing; 4 – according to the mode of monitoring the diagnostic object and the frequency of use; 5 – by the method of processing information and presenting results; 6 – by type of programming, indication and registration; 7 – according to the degree of unification and automation.
1 sign: 8 – performance monitoring; 9 – control and diagnostics; 10 – diagnostics; 11 – performance prediction; 12 – forecasting control; 13 – control control;
2 sign: 14 – built-in; 15 – external; 16 – mixed; 17 – motionless; 18 – movable;
3 sign: 19 – operational; 20 – pre-launch; 21 – preventive; 22 – technological; 23 – specialized; 24 – universal;
4 sign: 25 – with static mode; 26 – with dynamic mode; 27 – with continuous monitoring; 28 – with periodic monitoring; 29 – with sequential fault finding; 30 – with combined troubleshooting;
5 sign: 31 – analog; 32 – discrete; 33 – analog-discrete; 34 – with a tolerance assessment of the results; 35 – with quantitative assessment of results;
6 sign: 36 – with external programming; 37 – with internal programming; 38 – with centralized display and registration; 39 – with mixed indication and registration; 40 – with autonomous indication;
7 sign: 41 – unified; 42 – non-standardized; 43 – semi-automatic; 44 – automatic.
Classifying SRDK as an integral part of funds, they can be divided into the following funds:
universal application (computer-based) and means of specialized application (diagnostic stands);
built-in control and means with external control;
automatic (over 90% of operations are performed automatically), automated (40% - 90% of operations are performed automatically) and manual.
The STD classification makes it possible to describe the purpose of control means, methods of control and communication with the object, methods of obtaining and processing information.
The most widely used are STDs that assess the technical condition of an object at the time of inspection (STDs with performance prediction are promising).
SrDC parameters.
SRDK as a means of technical operation of RES can be classified into
information and measuring instruments for general use (voltmeters, ammeters, oscilloscopes, generators, etc.);
simulators and system parameter meters (various testers);
simulators of signals of certain types of electronic zones;
complex instruments for checking the operating condition of the REUiS;
complex stands for diagnosing, monitoring, adjusting and restoring REUiS;
diagnostic complexes for setting up complex systems;
automatic and automated devices and computer-based control systems.
The main parameters of the SDK are: measurement accuracy, reproduction accuracy of emitted signals, information productivity, instrumental reliability, resolution, degree of automation. All of the listed parameters relate to the SrDC derivatives. The technical parameters of the SRDK are the same technical parameters that were considered for the REUiS (operating conditions and reliability parameters are taken into account).
Diagnostic tools are also objects of technical operation and diagnostic objects; for this purpose, they provide self-monitoring modes, which are implemented using built-in or external systems of monitoring and diagnostic tools.
The accuracy of measuring instruments can be assessed by a measure of accuracy, where is the root-mean-square error. The main share of the measurement error comes from primary transducers and elements of the measuring path. In general, it is determined by the expression: 
, where is the root-mean-square error of the converters, is the mean square error of the normalizers, is the mean square error of the switches, and is the mean square error of the measuring device itself.
The accuracy of reproduction of simulation signals is characterized by errors in electrical or technical and functional parameters. The productivity of the SRDK is set by the average operational duration of diagnosis or the number of REUiS diagnosed for a given interval T: , where is the duration of diagnosis. The performance of the SRDK depends on the input capacities, as well as on the time the means are ready for diagnostics. Input capacity refers to the maximum number of diagnostic indicators that can be determined during the diagnostic process. The resolution of the SDK characterizes the component of the output information, which determines the possibility of separately reproducing data from two different sources (signals of one block or signals about the state of two different blocks). The degree of automation shows the number of automated operations relative to their total number, is a ratio. As indicators of the SRDC, the technical utilization coefficient SRDC () and its various modifications can be used.
Diagnostic software
Among diagnostic software computer networks, we can highlight special systems network management systems (Network Management Systems) - centralized software systems, which collect data about the state of network nodes and communication devices, as well as data about traffic circulating in the network. These systems not only monitor and analyze the network, but also perform network management actions in automatic or semi-automatic mode - enabling and disabling device ports, changing bridge parameters, address tables of bridges, switches and routers, etc. Examples of control systems include popular systems HPOpenView, SunNetManager, IBMNetView.
System Management tools perform functions similar to those of control systems, but in relation to communications equipment. At the same time, some functions of these two types of management systems may be duplicated; for example, system management tools can perform simple analysis of network traffic.
Expert systems. This type of system accumulates human knowledge about identifying the causes of abnormal operation of networks and possible ways bringing the network into operational state. Expert systems are often implemented as separate subsystems of various network monitoring and analysis tools: network management systems, protocol analyzers, network analyzers. The simplest version of an expert system is a context-sensitive help system. More complex expert systems are so-called knowledge bases that have elements artificial intelligence. An example of such a system is expert system, built into Cabletron's Spectrum control system.
Protocol Analyzers
During the design of a new or modernization old network there is often a need for quantitative measurement some characteristics of the network, such as, for example, the intensity of data flows along network communication lines, delays that occur at various stages of packet processing, response times to requests of one type or another, the frequency of occurrence of certain events and other characteristics.
For these purposes, various tools can be used, and above all, monitoring tools in network management systems, which have already been discussed earlier. Some measurements on the network can also be performed by software meters built into the operating system, an example of this is the OS component Windows Performance Monitor. Even modern cable testers are capable of capturing packets and analyzing their contents.
But the most advanced network research tool is a protocol analyzer. The process of protocol analysis involves capturing packets circulating in the network that implement one or another network protocol, and studying the contents of these packages. Based on the results of the analysis, it is possible to make reasonable and balanced changes to any network components, optimize its performance, and troubleshoot problems. Obviously, in order to draw any conclusions about the impact of a change on the network, it is necessary to analyze the protocols both before and after the change is made.
A protocol analyzer is either a stand-alone specialized device or Personal Computer, usually portable, Htebook class, equipped with a special network card and appropriate software. The network card and software used must match the network topology (ring, bus, star). The analyzer connects to the network in the same way as a regular node. The difference is that the analyzer can receive all data packets transmitted over the network, while a regular station can only receive those addressed to it. Software analyzer consists of a core that supports the operation network adapter and decoding the received data, and additional program code, depending on the type of topology of the network under study. In addition, a number of protocol-specific decoding routines, such as IPX, are supplied. Some analyzers may also include an expert system that can provide the user with recommendations on what experiments should be performed in a given situation, what certain measurement results may mean, and how to eliminate certain types of network faults.
Despite the relative diversity of protocol analyzers on the market, there are some features that are common to all of them to one degree or another:
User interface. Most analyzers have a developed user-friendly interface, usually based on Windows or Motif. This interface allows the user to: display traffic intensity analysis results; receive instant and average statistical assessment of network performance; set certain events and critical situations to track their occurrence; decode protocols of different levels and present the contents of packets in an understandable form.
Capture buffer. Buffers of different analyzers differ in size. The buffer can be located on the installed network card, or space may be allocated for it in the RAM of one of the computers on the network. If the buffer is located on the network card, then it is managed in hardware, and due to this, the input speed increases. However, this makes the analyzer more expensive. If the performance of the capture procedure is insufficient, some information will be lost and analysis will be impossible. The buffer size determines the analysis capabilities of more or less representative samples of the captured data. But no matter how large the capture buffer is, sooner or later it will fill up. In this case, either the capture stops or the filling starts from the beginning of the buffer.
Filters. Filters allow you to control the data capture process, and thereby save buffer space. Depending on the value of certain packet fields specified as a filter condition, the packet is either ignored or written to the capture buffer. The use of filters significantly speeds up and simplifies the analysis, as it eliminates the viewing of unnecessary this moment packages
Switches are certain conditions specified by the operator for starting and stopping the process of capturing data from the network. Such conditions may include the execution of manual commands to start and stop the capture process, time of day, duration of the capture process, and the appearance of certain values in data frames. Switches can be used in conjunction with filters, allowing for more detailed and nuanced analysis, as well as more productive use of limited capture buffer space.
Search. Some protocol analyzers allow you to automate the viewing of information in the buffer and find data in it based on specified criteria. While filters check the input stream to see if it matches the filter conditions, search functions are applied to the data already accumulated in the buffer.
The analysis methodology can be presented in the following six stages:
1. Data capture.
2. View captured data.
3. Data analysis.
4. Search for errors. (Most analyzers make this job easier by detecting error types and identifying the station from which the error packet came.)
5. Performance research. The network bandwidth utilization rate or the average response time to a request is calculated.
6. Detailed study of individual sections of the network. The content of this stage is specified as the analysis proceeds.
Typically, the process of analyzing protocols takes relatively little time - 1-2 business days.
Most modern analyzers allow you to analyze several global network protocols at once, such as X.25, PPP, SLIP, SDLC/SNA, frame relay, SMDS, ISDN, bridge/router protocols (3Com, Cisco, Bay Networks and others). Such analyzers allow you to measure various parameters protocols, analyze traffic on the network, conversion between local and global network protocols, delay on routers during these conversions, etc. More advanced devices provide the ability to simulate and decode global network protocols, “stress” testing, measuring maximum throughput, quality testing services provided. For the sake of versatility, almost all WAN protocol analyzers implement testing functions for the LAN and all major interfaces. Some devices are capable of analyzing telephony protocols. And the most modern models can decode and present all seven in a convenient way. OSI levels. The emergence of ATM led to manufacturers starting to equip their analyzers with tools for testing these networks. Such devices can conduct full testing of E-1/E-3 ATM networks with monitoring and simulation support. The set of service functions of the analyzer is very important. Some of them, such as the possibility remote control device, are simply irreplaceable.
Thus, modern WAN/LAN/DTM protocol analyzers can detect errors in the configuration of routers and bridges; set the type of traffic sent over global network; determine the speed range used, optimize the ratio between throughput and the number of channels; localize the source of incorrect traffic; perform testing serial interfaces and full ATM testing; carry out full monitoring and decoding of the main protocols on any channel; analyze statistics in real time, including traffic analysis local networks through global networks.
NET DIAGS command
Used to interactively download the network diagnostic utility.
NET DIAGS-Personal NetWare Diagnostics utility allows you to monitor network operations. This information is mainly of interest to those users who have a good understanding of the network's functions.
Specifically, it allows you to view and monitor other groups on the network, compare client and server traffic, compare server usage, client disk information, view configuration information, server and client statistics, and test server and client connections.
Utility network diagnostics has versions for DOS and MS Windows, which have similar functions, but some tools are unique and are only available in the DOS version.
By default, network diagnostics are enabled during network installation. To disable or re-enable it after disabling, use the SETUP utility. This utility automatically adds the VLM=NMR.VLM command to your computer's NET.CFG file. Enabling this command automatically starts the Network Management Responder module when the operating system starts.
IN Windows utility network diagnostics has GUI. To access it, open the Personal NetWare group in Program Manager and select the Network Diagnostics icon. The NetWork Diagnostics window appears.
The DOS version has all the diagnostic tools included in the Windows version, plus some additional tools. To access them, type the command in response to the system prompt:
PNWDIAGS
or
NET DIAGS
The main menu is displayed. Here, an additional (not available in the Windows version) Select Data tool allows you to view other network workgroups and manage names network files without leaving your working group. Save LANalyzer Name File allows you to save files created with Associate Network Names as files viewable in LANalyzer for Windows.
To view the activity of another workgroup, select Select a Workgroup in the main menu and specify the desired one in the displayed list of workgroups. Not all workgroups may be displayed in the list. For search the desired group use NET command WGFIND.
All network segments are available for viewing. Each network is identified by a unique hexadecimal number. To view another network, select Select Data from the main menu and Select a Network from the Data Selection Items menu. A list of available network numbers is displayed. Select the desired network in it, return to the main menu and select View Configuration. You will see all computers (nodes) on the network, including clients and servers. Only host names are shown. Associate Network Names option allows you to display their names.
To obtain network names, select Select Data from the main menu, and Select a Network from the Data Selection Items menu. Select Network and Associate Network Names from the Data Selection Items menu. Then select Find Diagnostics User Names from the Network Names menu. To view the names associated with each node, return to the main menu and select View Configuration.
Information about network traffic allows you to identify the causes of problems or overload on a particular computer. You can get this information using Compare Data and Select Nodes. From the Compare Options menu, select Traffic. Network traffic will be displayed for the selected nodes. To exit, press Esc.
Viewing usage information Server utilization, you can see the ratio of the computer processed local queries to remote and the actual number of packets processed by the server. This helps distribute system resources. In addition, you can see connection information, the number of open files and server activity. To obtain this information, select Local/Remote Utilization or Server Utilization from the Compare Options menu. F1 displays the help screen.
Selecting Resource Distribution or Resource Efficiency from the Compare Options menu provides disk usage data. Using Select View Statistics, you can select the desired network nodes and view statistics on them, and Choose Test Connections displays the Connection Tests menu and allows you to check the connection between selected computers on the network (Point to point item) or all connections between all computers.