Monitor and Maintain a Multi-User Networked Operating System 114053
Monitor and maintain a multi-user networked operating system 114053
PURPOSE OF THE UNIT STANDARD This unit standard is intended To provide proficient knowledge of the areas covered For those working in, or entering the workplace in the area of Data Communications & Networking
People credited with this unit standard are able to: Monitor the performance of a multi-user networked operating system Resolve problems with a multi-user networked operating system Maintain a multi-user networked operating system. The performance of all elements is to a standard that allows for further learning in this area.
LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING The credit value of this unit is based on a person having prior knowledge and skills to: Install and configure a multi-user networked operating system.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 55
INDEX Competence Requirements Page Unit Standard 114053 alignment index Here you will find the different outcomes explained which you need to be 57 proved competent in, in order to complete the Unit Standard 114053. Unit Standard 114053 59 Monitor the performance of a multi-user networked operating system 62 Resolve problems with a multi-user networked operating system 68 Maintain a multi-user networked operating system 84 Self-assessment Once you have completed all the questions after being facilitated, you need to check the progress you have made. If you feel that you are competent in the areas mentioned, you may tick the blocks, if however you feel that you 94 require additional knowledge, you need to indicate so in the block below. Show this to your facilitator and make the necessary arrangements to assist you to become competent.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 56
Unit Standard 114053 – Alignment Index SPECIFIC OUTCOMES AND RELATED ASSESSMENT CRITERIA SO 1 Monitor the performance of a multi-user networked operating system The monitoring explains system performance measures, and outlines and justifies a AC 1 monitoring strategy. AC 2 The monitoring is carried out in accordance with the monitoring strategy. The monitoring compares the results produced from performance monitoring, with user AC 3 perception of performance, and identifies discrepancies between the two measures. AC 4 The monitoring identifies performance-limiting factors. The monitoring outlines recommendations to improve performance, and justifies them using AC 5 performance analysis. SO 2 Resolve problems with a multi-user networked operating system. The resolution ensures that the operating system is returned to service, free of problem AC 1 symptoms. AC 2 The resolution uses an industry recommended procedure to diagnose problems. The resolution ensures that descriptions of solutions to the problems are justified by AC 3 diagnostic evidence. AC 4 The resolution uses a diagnostic tool to diagnose problems. The resolution ensures that the problem causes and resolutions are documented according to AC 5 industry recommended practice. SO 3 Maintain a multi-user networked operating system. The maintenance ensures that any configurations made to the multi-user networked AC 1 operating system are in accordance with organisation requirements. The maintenance ensures that changes to the multi-user networked operating system AC 2 maintain the integrity and security of the software. The maintenance ensures that monitoring and tuning of the system maximises operation and AC 3 performance, and meets manufacturer and organisation specifications.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 57
CRITICAL CROSS FIELD OUTCOMES UNIT STANDARD CCFO WORKING Work effectively with others as a member of an organisation.
UNIT STANDARD CCFO ORGANISING Organise and manage him/her self and his/her activities responsibly and effectively.
UNIT STANDARD CCFO COLLECTING Collect, analyse, organise, and critically evaluate information.
UNIT STANDARD CCFO SCIENCE Use science and technology effectively and critically, showing responsibility towards the environment and health of others.
UNIT STANDARD CCFO DEMONSTRATING Demonstrate an understanding of the world as a set of related systems by recognising that problem solving contexts do not exists in isolation.
UNIT STANDARD CCFO CONTRIBUTING Contribute to his/her full personal development and the social and economic development of the society at large by being aware of the importance of: reflecting on and exploring a variety of strategies to learn more effectively, exploring education and career opportunities and developing entrepreneurial opportunities ESSENTIAL EMBEDDED KNOWLEDGE
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 58
All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.
SOUTH AFRICAN QUALIFICATIONS AUTHORITY REGISTERED UNIT STANDARD:
Monitor and maintain a multi-user networked operating system
SAQA US UNIT STANDARD TITLE ID 114053 Monitor and maintain a multi-user networked operating system ORIGINATOR SGB Information Systems and Technology PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY - FIELD SUBFIELD Field 10 - Physical, Mathematical, Computer and Life Sciences Information Technology and Computer Sciences ABET UNIT STANDARD PRE-2009 NQF LEVEL NQF LEVEL CREDITS BAND TYPE Undefined Regular Level 5 Level TBA: Pre-2009 was 6 L5 REGISTRATION STATUS REGISTRATION START REGISTRATION END SAQA DECISION DATE DATE NUMBER Reregistered 2018-07-01 2023-06-30 SAQA 06120/18 LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT 2024-06-30 2027-06-30
In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.
This unit standard does not replace any other unit standard and is not replaced by any other unit standard.
PURPOSE OF THE UNIT STANDARD This unit standard is intended To provide proficient knowledge of the areas covered For those working in, or entering the workplace in the area of Data Communications & NetworkingPeople
credited with this unit standard are able to: Monitor the performance of a multi-user networked operating system Resolve problems with a multi-user networked operating system Maintain a multi-user networked operating system. The performance of all elements is to a standard that allows for further learning in this area.
LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING The credit value of this unit is based on a person having prior knowledge and skills to: Install and configure a multi-user networked operating system.
Specific Outcomes and Assessment Criteria:
SPECIFIC OUTCOME 1 Monitor the performance of a multi-user networked operating system OUTCOME RANGE
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 59
Performance specifications; Comparison of results; Limitations; Recommendations.
ASSESSMENT CRITERIA
ASSESSMENT CRITERION 1 1. The monitoring explains system performance measures, and outlines and justifies a monitoring strategy.
ASSESSMENT CRITERION 2 2. The monitoring is carried out in accordance with the monitoring strategy.
ASSESSMENT CRITERION 3 3. The monitoring compares the results produced from performance monitoring, with user perception of performance, and identifies discrepancies between the two measures.
ASSESSMENT CRITERION 4 4. The monitoring identifies performance-limiting factors.
ASSESSMENT CRITERION 5 5. The monitoring outlines recommendations to improve performance, and justifies them using performance analysis.
SPECIFIC OUTCOME 2 Resolve problems with a multi-user networked operating system. OUTCOME RANGE Problem-identification; Symptoms; Diagnostics; Documentation.
ASSESSMENT CRITERIA
ASSESSMENT CRITERION 1 1. The resolution ensures that the operating system is returned to service, free of problem symptoms.
ASSESSMENT CRITERION 2 2. The resolution uses an industry recommended procedure to diagnose problems.
ASSESSMENT CRITERION 3 3. The resolution ensures that descriptions of solutions to the problems are justified by diagnostic evidence.
ASSESSMENT CRITERION 4 4. The resolution uses a diagnostic tool to diagnose problems.
ASSESSMENT CRITERION 5 5. The resolution ensures that the problem causes and resolutions are documented according to industry recommended practice.
SPECIFIC OUTCOME 3 Maintain a multi-user networked operating system. OUTCOME RANGE Security; Integrity; Backups; Performance factors.
ASSESSMENT CRITERIA
ASSESSMENT CRITERION 1 1. The maintenance ensures that any configurations made to the multi-user networked operating system are in accordance with organisation requirements.
ASSESSMENT CRITERION 2 2. The maintenance ensures that changes to the multi-user networked operating system maintain the integrity and security of the software.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 60
ASSESSMENT CRITERION 3 3. The maintenance ensures that monitoring and tuning of the system maximises operation and performance, and meets manufacturer and organisation specifications.
UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS Accreditation Process: The relevant Education and Training Quality Authority (ETQA) must accredit providers before they can offer programs of education and training assessed against unit standards.
Moderation Process: Moderation of assessment will be overseen by the relevant ETQA according to the moderation guidelines in the relevant qualification and the agreed ETQA procedures.
UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 1. Performance of all elements is to be carried out in accordance with organisation standards and procedures, unless otherwise stated. Organisation standards and procedures may cover: quality assurance, documentation, security, communication, health and safety, and personal behaviour. An example of the standards expected is the standards found in ISO 9000 Certified Organisations. 2. Performance of all elements complies with the laws of South Africa, especially with regard to copyright, privacy, health and safety, and consumer rights. 3. All activities must comply with any policies, procedures and requirements of the organisations involved, the ethical codes of relevant professional bodies and any relevant legislative and/ or regulatory requirements. 4. Performance of all elements should be performed with a solid understanding of the use of development tools needed in the areas applicable to the unit standard. Examples of such tools are, but is not limited to CASE tools, programming language editors with syntax checking, program source version control systems systems.
Critical Cross-field Outcomes (CCFO): UNIT STANDARD CCFO WORKING Work effectively with others as a member of an organisation. UNIT STANDARD CCFO ORGANISING Organise and manage him/her self and his/her activities responsibly and effectively. UNIT STANDARD CCFO COLLECTING Collect, analyse, organise, and critically evaluate information. UNIT STANDARD CCFO SCIENCE Use science and technology effectively and critically, showing responsibility towards the environment and health of others. UNIT STANDARD CCFO DEMONSTRATING Demonstrate an understanding of the world as a set of related systems by recognising that problem solving contexts do not exists in isolation. UNIT STANDARD CCFO CONTRIBUTING Contribute to his/her full personal development and the social and economic development of the society at large by being aware of the importance of: reflecting on and exploring a variety of strategies to learn more effectively, exploring education and career opportunities and developing entrepreneurial opportunities.
REREGISTRATION HISTORY As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015.
UNIT STANDARD NOTES Supplementary information: 1. Installation and configurationof a networked operating system will be done on a "clean" server, or as an upgrade of an existing server. 2. The installation should reflect the principles and techniques of at least one given multi-user networked operating system, and the practitioner will be aware of other similar operating systems. 3. At least two different computer architectures should be used in the installation process, in ways that demonstrate the customisation process.
Sub-Sub-Field (Domain): Data Communications and Networking.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 61
Monitor the performance of a Multi-user networked operating system Time: 90 minutes Activity: Self and Group
AC 1 he monitoring explains system performance measures, and outlines and justifies a monitoring strategy. T It is not enough to merely ensure for effective installation of the multi-user operating system software. You will need to regularly monitor the performance of the operating system to check for, identify and avoid likely problems.
As prevention is always better than cure, lots of costs can be avoided in downtime of a system where likely future problems can be identified and avoided.
In order to monitor the performance of the system effectively, we need to understand how the system functions and how and what checks can be done to measure its performance.
Some of the most important measurements for performance monitoring include: • Processor utilization • Hard-disk I/O rates • Memory utilization • Page file activity
A good way to estimate how many users a server can support is to measure system performance with two to five users on the system, and then scale the results.
The above performance indicators can be tested at any time by accessing the control panel and administrative function. Each one of the above could then be monitored independently and as a whole. A report can also be generated on the performance of the system for later analysis.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 62
AC 2 he monitoring is carried out in accordance with the monitoring strategy Brainstorm T Brainstorm in your groups what possible problems or performance issues could occur and how to resolve them.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 63
Design a strategy to conduct maintenance checking procedures to be conducted on the Multi-user Network System You will need to consider the following factors when designing the maintenance strategy: What maintenance tasks needs to be carried out?
How frequently will these tasks need to be carried out?
What resources will be required to conduct the maintenance procedures?
When will be the best suited time to conduct theses procedures?
How will you deal with and resolve any problems identified?
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 64
AC 3 he monitoring compares the results produced from performance monitoring, with user perception of performance, and T identifies discrepancies between the two measures What is a Multi-User Operating System? A multi-user operating system (OS) is a computer system that allows multiple users that are on different computers to access a single system's OS resources simultaneously, as shown in Figure 1. Users on the system are connected through a network. The OS shares resources between users, depending on what type of resources the users need. The OS must ensure that the system stays well-balanced in resources to meet each user's needs and not affect other users who are connected.
Some examples of a multi-user OS are Unix, Virtual Memory System (VMS) and mainframe OS. Multi-user operating systems were originally used for time-sharing and batch processing on mainframe computers. These types of systems are still in use today by large companies, universities, and government agencies, and are usually used in servers, such as the Ubuntu Server edition (18.04.1 LTS) or Windows Server 2016. The server allows multiple users to access the same OS and share the hardware and the kernel, performing tasks for each user concurrently.
Multi-User Operating System Security Since multi-user OS have several users accessing the system resources simultaneously, it is very important for the system administrators to implement security features within the system. These features could include account separation, user groups, roles and permissions.
Account separation is one of the most important security features that needs to be implemented. This is vital in order to maintain file and content protection, integrity and privacy. Each user must have their own separate account, giving them private work and storage space within the system.
Also, user groups, roles and permissions should be created and assigned to each user to ensure others do not interfere with or delete other users' work, purposefully or accidentally.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 65
A user group is a group of users or people that have similar interests or jobs with access to specific information they might need. A role is defined as an assignment of rights and rules that a user is assigned by the administrator or superuser. Permissions is the authorization of a user to access specific resources or files on a particular computer system or network.
AC 4 he monitoring identifies performance-limiting factors. Users interact indirectly through a T collection of system programs that make up the operating system interface. The interface could be: A GUI, with icons and windows, etc. A command-line interface for running processes and scripts, browsing files in directories, etc.
Or, back in the olden days, a non-interactive batch system that takes a collection of jobs, which it proceeds to churn through (e.g. payroll calculations, market predictions, etc.) Processes interact by making system calls into the operating system proper (i.e. the kernel). Though we will see that, for stability, such calls are not direct calls to kernel functions.
Typically, operating systems will offer the following services to processes: Program execution: The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error) I/O operations: A running program may require I/O, which may involve a file or an I/O device File-system manipulation: Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management.
Interprocess Communication (IPC): Allowing processes to share data through message passing or shared memory. Typically, operating systems will offer the following internal services: Error handling: what if our process attempts a divide by zero or tries to access a protected region of memory, or if a device fails? Resource allocation: Processes may compete for resources such as the CPU, memory, and I/O devices. Accounting: e.g. how much disk space is this or that user using? How much network bandwidth are we using?
Protection and Security: The owners of information stored in a multi-user or networked computer system may want to control use of that information, and concurrent processes should not interfere with each other
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 66
The user process calls the system call wrapper function from the standard C library The wrapper function issues a low-level trap instruction (in assembly) to switch from user mode to kernel mode
To get around the problem that no call can directly be made from user space to a specific function in kernel space: Before issuing the trap instruction, an index is stored in a well- known location (e.g. CPU register, the stack, etc.). Then, once switched into kernel space, the index is used to look up the desired kernel service function, which is then called. Some function calls may take arguments, which may be passed as pointers to structures via registers.
AC 5 he monitoring outlines recommendations to improve performance, and justifies them T using performance analysis. An OS is possibly the most complex system that a computer will run, and it not yet clear (nor may it ever be) how to design an operating system to best meet the many and varied requirements placed on it. The internal structure of OSes can vary widely
We can start by defining goals and specifications: Affected by choice of hardware, type of system User goals and System goals User goals - operating system should be convenient to use, easy to learn, reliable, safe, and fast System goals - operating system should be easy to design, implement, and maintain, as well as flexible, reliable, error-free, easy to extend, and efficient OS architectures have evolved over the years, generally trying to better balance efficiency and stability
Policy: What will be done? Mechanism: How to do it? The separation of policy from mechanism is a very important principle, it allows maximum flexibility if policy decisions are to be changed later An architecture that supports extendible file systems is a good example Rather than hard code a particular file system into the kernel code, create an abstract file- system interface with sufficient flexibility that it can accommodate many file system implementations, e.g.: NTFS, EXT, FAT.
MS-DOS - written to provide the most functionality in the least space
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 67
Not divided into modules Although MS-DOS has some structure, its interfaces and levels of functionality are not well separated - the highest layer is allowed to call the lowest layer. So, it was easy for a user process (accidentally or on purpose) to de-stabilise the whole system, which is often what happened, even up until MS-DOS based Windows ME.
The operating system is divided into a number of layers (levels), each built on top of lower layers. The bottom layer (layer 0), is the hardware; the highest (layer N) is the user interface. With modularity, layers are selected such that each uses functions (operations) and services of only lower-level layers
Importantly for stability, modern CPUs offer protected mode, which means transition between layers is controlled by hardware Attempts of software to run instructions or access memory regions that are higher privilege will result in the CPU raising a hardware exception (e.g. divide by zero, attempt to access hardware directly, etc.) Lends itself to simpler construction, since layers have well-defined functionality and can be tested independently or altered with minimal impact on the rest of the OS (e.g. lowest level could be adapted to different CPU architectures with minimal impact on higher layers) Eike Ritter Operating Systems with C/C++ Overview Operating System Topics OS Services OS Architecture Virtual Machines Design OS Architecture Examples Strict Layered Consider a file system.
The actual file-system can be implemented in a layer above a layer that reads and writes raw data to a particular disk device, such that the file system will work with any device implemented by the lower layer (e.g. USB storage device, floppy disk, hard disk, etc.). In practice, however, it can be difficult to decide how many layers to have and what to put in each layer to build a general purpose operating system
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 68
Resolve problems with a multi-user networked operating system Time: 90 minutes Activity: Self and Group
AC 1 he resolution ensures that the operating system is returned to service, free of problem symptoms T The following findings is out of the personal experience of a diagnostic problem expert. Identifying problems is often just a matter of elimination. You have a problem and you start checking the parts that are not causing it. For example, if bad data is written into a database then the GUI would be the unlikely cause.
A well-designed system is made of a huge number of small parts and has test cases for every part. So you can use those test cases to check if each part works just fine. You might have to make a few changes to the parts that you suspect and if you can’t find the problem then you start assembling various parts together to see if they cause the problem when combined.
My biggest challenge once was an application that was developed by someone else, which worked fine. Well, the machine that it ran on had an occasional Blue Screen Of Death but that was bad hardware. Probably. But a customer who recently started using the same software complained as his antivirus software gave warnings and quarantined the application! Which was strange as our own virus scanner had no problems with it. So, was the customer infected?
My task: find out who was right… So I had to replicate the customer’s problem. That was simple: use their virus scanner. And indeed, the application was marked as malware for unknown reasons. Probably a false positive because the compiled binary probably had some code that matched a specific virus signature. I knew my system was clean so I recompiled it and checked the result. Still a virus warning…
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 69
So, that left me with a very unclear problem. Somewhere within the application was some code that triggered this warning. And the only way to find it was by eliminating parts of the code until no warning was been given.
It’s a guessing game where you have to guess a number between 1 and 100. And all you get is a higher (warning) or lower (no warning) signal. So you eliminate half the code and check if the warning is still there. Then repeat this like you would guess a number between 1 and 100. You should get there within 8 guesses or so.
I finally eliminated the problem to a function that uses a Windows key-hook to listen to keyboard events. This is quite innocent and many applications use this to respond to certain hotkeys. Our app had a specific hotkey so it was a very important part of the code. So I had to find out why calling it from our application caused a warning while so many other applications have no problems. Which meant studying the documentation of this specific API function.
And I discovered that it is called with a handle of an application instance to keep the key- hook within that instance. This was important as the specific code that handles the key-hook gets injected inside this application instance. In our case, that would be Microsoft Outlook. But instead of using the handle of Outlook, we used NULL as instance handle, resulting in the key-hook becoming a global key-hook.
It meant that it was injected in each and every process on the computer! Including some important processes of Windows itself. And minor memory issues within the code could trigger a fatal crash resulting in the BSOD that I’ve mentioned. Whomever created that piece of code had not thought of this and I had to fix it by retrieving the proper instance handle and use that instead of NULL.
A very easy change that solved the virus problem as the virus scanner now saw that we weren’t installing a global key-hook anymore. As an added bonus, it also solved the BSOD that we never saw as a problem as we blamed bad hardware for this…
It took me 5 days to discover that we were calling a single function with a wrong parameter. That was 15 years ago and I still remember how slow this process was as I had to comment out code and recompile everything while making sure there were no compile errors.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 70
And whomever wrote the application didn’t understand modular programming or OO programming very well as the code was a huge mess… Nowadays, code is preferably developed as small components where each component can operate independently from the other components. This allows better testing and makes it easier to find the cause of a problem.
AC 2 he resolution uses an industry recommended procedure to diagnose problems T How to troubleshoot operating system problems and tools used As a matter of fact, operating systems are not designed to utmost perfection since at times they suffer from a number of problems. Such problems can be very inconveniencing if one are not familiar with the troubleshooting tools. Hence one should be aware of all these techniques which can resolve the problem so one can continue working without any problems. Below are some of the common operating problems and their troubleshooting tools.
Common symptoms BSOD The blue screen of death is a Windows stop error that clearly points onto hardware malfunction or spoilt device drivers. One may decide to start in safe mode or carry out some System Restore.
Failure to boot Failure of one's computer to boot can be as a result of a corrupt operating system or some possible changes in one's system's boot order. One can go to the BIOS setup and try to look at the boot sequence. If that does not work, then one should consider reinstalling the Windows operating system since the problem could be far much serious.
Improper shutdown At times, one's computer may shutdown improperly due to instances of power loss or crushing. In case of such an incidence, restarting the computer might not take one directly to Windows and therefore one should run Windows Error Recovery which automatically checks the file system and drives for any problems. With that, all system files are placed in their right positions and Windows now starts without any problems.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 71
Spontaneous shutdown/restart This is a problem that mostly occurs in instances where one's computer keeps looping over the start-up process where it appears to be starting and then restarts. In such a case, the first step should be to try and establish the occurrence point of the problem either in the course of the BIOS check where the Power on Self-test is undergoing among some other possible reasons. Once that is established, then one can easily decide if the problem is hardware related or related to the Windows configuration.
RAID not detected during installation This is an error message that tends to appear when one are installing an operating system and some of the files required are not found. In such a case, one might open the registry in safe mode to check for the files or restart the installation process with a new installation media.
Device fails to start Failure of one's device can be very frustrating. In most cases, it normally results from a computer crush or some other hardware related problems. In such a case, try to carry out hardware diagnostics so as to try and establish the problem. One can also decide to boot the computer from a Windows installation media to try and get one's computer to restart.
Missing dll message The missing dll message mainly appears when the dynamic link libraries are missing. This could be as a result of using many third party applications leading to much redundancy in all the applications. Dlls have many different versions and therefore a lack of update can lead to such a pop-up message. Overwriting older versions with new versions can be very dangerous since there can be some possible malfunction.
Services fail to start At times, starting one's system might become a problem due to the fact that one can receive a pop-up message informing one that there is a failure in the starting of one or more services. Since it is very difficult to establish the problem, some information should be collected. One can manually start services at the Windows services so as to see if any of them will fail.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 72
In addition to manually starting the services, try to look at processes the services depend on since the process may have to start so that the service can also begin running. One might also need to install a special type of software that will manage the service, rebuilt it and reconfigure it so that every inch of that service starts properly.
Compatibility error The Windows operating system compatibility error mainly appears when some of the old application versions are not working properly after a windows upgrade. In such cases, Windows has an in-built capability that allows one to change the compatibility of the applications.
One can also choose to run the program in its compatibility mode so as to choose the most appropriate operating system for the application. In some cases, the old and out-dated applications can also run in a new version of Windows as long as they are in their compatibility mode.
Slow system performance A slow system performance is a problem that can be fixed by making sure that onehas installed the latest versions of all items running in one's computer system such as the operating system, drivers and applications. All security patches should be up to date and all Windows updates should functional.
Slow system performance could be as a result of some in-built configurations such as running the CPU slowly when on battery and not on power. Malicious software could also be a cause of slow system performance hence a computer scan can be very essential.
Boots to safe mode The safe mode boot option is one that is usually available prior to starting the operating system. When one presses F8, one receives a menu of advanced options from where one can choose to boot one's computer in safe mode.
By using the safe mode boot for one's operating system, one should be in a position to enable network drivers among some many other functions. In addition, booting through the safe mode may not boot the desktop but takes one directly to the command prompt rather than heading to the graphics display.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 73
File fails to open In a Windows operating system, all files normally have distinct file extensions such as .docs and .ppt. A file with a specific file extension can only be opened by an application designed to open it. Trying to open a file whose file extension is not compatible with a certain program can result into an error message of the file failing to open. Installation of the specific application to open specific file extensions can be a solution. In other cases, some modifications can be made on the applications inside Windows.
Missing NTLDR Missing NTLDR message is one that is very common on older versions of Windows such as the Windows XP operating system. NTLDR files are very crucial and highly important boot files for one's computer and their deletion means that one's system will not start. To deal with this, one should start the computer with a boot disk so that one can copy back the deleted files onto the hard drive, then carry out a system restart and the Windows operating system begins to run.
Missing Boot.ini The missing operating system message mainly appears in instances where one is trying to access a drive that is configured as a boot device but with the absence of a boot loader in one's computer. With such an error message, one may need to get into the recovery console environment and run the check disk command to check if the OS is in one's computer. In other case, one should only carry out updates on the Master Boot Record and everything gets right on track.
Missing operating system When the operating system isn't installed or it is corrupted, then this message appears and this message indicated that one has to do something about the installation of new windows.
Missing Graphical Interface The missing graphical interface normally results into a dark screen that appears in instances where Windows does not start up. User interfaces and login screens are absent and therefore there could be a problem with the video system. One should try to update the video driver or start the system in graphics mode for lower resolution graphics so as to get to a point of loading the new drivers.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 74
Graphical Interface fails to load The graphical interface probably fails to load due to the absence of the necessary graphics drivers or a problem with the video hardware. In such a case, try updating the video drivers or install a new version of the drivers.
Invalid boot disk The invalid boot disk error message mainly appears when there is a problem with one's operating system's boot order. On receiving such a message, make sure that no USB device is plugged in since the BIOS might be configured to boot from external USB devices instead of the local drive. In addition, one can make modifications onto the BIOS configuration so as to modify the devices that should boot first on one's computer.
Tools Here are the tools sued for the fixation;
Fixboot Fixboot command is used when one want to create a new boot sector for the operating system. By using this command, one might want to write some new booting sector in a particular partition. When using this command, one might also require using the DISKPART command so as to identify the part or section of the disk one wants to write the new boot sector.
Recovery console This is a powerful troubleshooting tool that gives one the mandate to change things on the operating system without having to start windows. It is however a very dangerous commands to use. This is a command that gives one complete control of the operating system in such a manner that one can make changes to it before it starts.
Fixmbr The Fixmbr command is one that one can access from the command prompt. This is a troubleshooting command that one should use when the need to build another Master Boot Record arises. One can also make changes on the drive's configurations, repartitions and reformats.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 75
Sfc The SFC operating system troubleshooting tool is one that one should prior to using one's system again in case one have ever been a victim of malware infection or hard drive corruption.
This is the System File Checker command which is able to carry out integrity scans on all the system files so as to check the validity of the operating system files. In case some malware infection replaced or brought about some damage to one of the system files, the System File Checker will identify it and prompt one to recover the file so as to put the appropriate one in place.
Repair disks The system repair disk is a troubleshooting environment that is available for windows where one receives the option to create a system recovery option, backup and restore options. There are many options normally available in this such as repair/start-up, system restore, image recovery among many others. In the repair disk option, one can also launch the system recovery options and commence all one's troubleshooting.
Pre-installation environments The pre-installed windows environment is an option that is mainly used when going through some recovery options or when setting up windows vista and 7. This is an environment where the desktop is usually unavailable. One can easily come up with one's own windows pre-installation environment. In addition, some of these PE tools can be downloaded and burnt onto a DVD ROM hence no need to come up with one.
MSCONFIG The MSCONFIG troubleshooting tool is an acronym for the Microsoft System Configuration Utility. This is a troubleshooting utility that one should use in instances where one's operating system is experiencing start-up problems, if the desktop is not loading or some possible malfunction of some applications.
With this utility, one are in a position to carry out some diagnostic activities through which all processes are broken down so as to establish where the problem is. This is a utility that gives one the ability to control all the boot process activities such as enabling and disabling the loading of some applications. In addition, one can make modifications and changes to some operating services if one does not want them to load when the operating system starts.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 76
DEFRAG The DEFRAG tool is another important operating system troubleshooting tool. This mainly stands for defragmentation which means putting files and folders in a proper order. Through defragmentation, one is able to bring many split files into one location for continuous viewing.
This is a troubleshooting tool that one should use when one are encountering problems with accessing hard drive files especially if the files are stored in different locations on the hard drive thus making the process of reading each file a challenge. This is a process that one can set to occur automatically using the task scheduler.
REGSRV32 The regsvr32 also known as the Microsoft Registry Server is a troubleshooting utility that tends to alter contents of the registry. With this application, one can easily make some DLL registration in addition to deregistration from the operating system.
The Microsoft Registry Server performs registry updates when one are troubleshooting problems related to dynamic link libraries that are used by the Windows operating system. . Once it updates, it informs the operating system of the DLL's location, its version among other information required by the application so as to use the dynamic link library.
REGEDIT With the computer registry being an important aspect of the operating system, it is one of the most important places one should not miss when carrying out operating system troubleshooting.
This is because it is in the registry where much information concerning applications, system configurations, services and running drivers is stored making it a very large and important database. In the registry, there is a program known as regedit or Registry Editor where one can gain full access to edit registry information. One can back up registry information, add keys and also delete keys.
Event viewer The event viewer is somewhat a special troubleshooting tool in that it is the one that enables one to see activities that are happening simultaneously in the OS. Since it's very difficult to establish all that's happening in the OS, the event viewer is a place where one are able to see all that's happening in the operating system.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 77
For instance, one may have a driver that is not properly functional and one can easily view it at the event viewer. The event viewer also keeps track of information on activities that occurred some period ago.
Safe mode The safe mode boot option is one that is usually available prior to starting the operating system. When one presses F8, one receives a menu of advanced options from where one can choose to boot one's computer in safe mode. By using the safe mode boot for one's operating system, one should be in a position to enable network drivers among some many other functions. In addition, booting through the safe mode may not boot the desktop but takes one directly to the command prompt rather than heading to the graphics display.
Command prompt The command prompt is considered to be one of the most powerful OS troubleshooting tools. The command prompt is a platform that can be accessed without necessarily having to start the operating system. In Windows XP version, one can access it from the installation media while in Windows & and Vista one can use the system recovery options to get to the command prompt. In the command prompt, one can make modifications to the operating system only if one is conversant with the modifications one is making.
It can be very dangerous to go to the command prompt, make some alterations on operating files or even delete them and then recovering them becomes a problem. Through the command prompt, one have complete control of the operating system since one can replace OS files and move them around since the OS is not yet booted.
Emergency repair disk Emergency repair disk should be carried out when there is an urgent need to carry out diagnosis on a drive that is not properly functional. One should use the system recovery option or repair disk option for this.
Automated system recovery An automated system recovery can be induced by running one's computer in safe mode and then selecting the system recovery option and the operating system moves to a specific restoration point. Generally, troubleshooting of operating system problems is an easy activity only when the right troubleshooting tools are used. It is therefore important that one is familiar with all the troubleshooting tools.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 78
AC 3 he resolution ensures that descriptions of solutions to the problems are justified by T diagnostic evidence A diagnostic program (also known as a Test Mode) is an automatic computer program sequence that determines the operational status within the software, hardware, or any combination thereof in a component, a system, or a network of systems.
Diagnostic programs ideally provide the user with guidance regarding any issues or problems found during its operation. Diagnostics programs may be simple or complex, operating unknowingly within everyday devices or awaiting their invocation to make more complex performance assessments. Everyday examples are a microwave oven that displays code F6 to warn of a shorted temperature probe or a garage door opener that flashes its control board's LED four times warning of critically misaligned safety sensors and impending shutdown.
Diagnostic programs are also inserted into consumer electronic products and electronic games. Sometimes if the owner of an electronic device asks the manufacturer how to access the hidden diagnostic program, they usually reply to the consumer saying that the information is considered to be 'propitary' and cannot be shared.
Early diagnostics programs were procedural instructions performed by humans not by computer programs. As computers became smaller, more mobile, computer programs were used to perform diagnostics tasks. In the late 1960s Volkswagen introduced the first on- board computer system with diagnostics provisions.
Methods of Operation The diagnostics program for a device or system may be independently located or integrated within. These Methods of Operation are arranged, more-or-less, in order of increasing complexity and their increasing value of diagnostics information. Background monitoring of system indicators, for statistical analysis of trends, and for recording abnormal events. Solution-based diagnostics, that test for known failure modes by identifying if their known symptoms are detected.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 79
Black box, which is testing of a mechanism without knowing how it works, and merely focusing on the accuracy of output data based on a known input. White box, which uses knowledge of a mechanisms inner functions for direct testing. Operation-oriented, a combination of both black and white box, with one or more black-box operations interleaved with one or more white-box operations. This mode of testing is not preferred, however some complex systems do not have the necessary interfaces to perform one or the other type independently.
Integrated background diagnostics that perform testing of system components during idle- time of a system. Operation-interleaved diagnostics that incorporate diagnostics into the normal operation of a system component, thus any marginal operating mode is immediately diagnosed. Examples of hardware components with features that assist a diagnostic program are: Modern hard drives have Self-Monitoring, Analysis and Reporting Technology (SMART) commands that provide information about internal error conditions, e.g., spin retry counts, bad sector counts, etc. Some systems may use Error Correcting Code (ECC) memory that logs memory failure events that were automatically corrected.
AC 4 he resolution uses a diagnostic tool to diagnose problems T Single-purpose diagnostic, also referred to as "Defined-purpose" diagnostic, such as a program that validates the Windows DirectX configuration.
Multi-purpose diagnostic, a monolithic program that performs multiple tasks that may or may not be suitable for all uses. This would be similar to a hammer that will perform well with nails, less so with screws, and poorly with nuts and bolts.
Modular diagnostic, which combines sets of single-purpose diagnostics, Lego-like, into an environment easily tailored to particular industry requirements. Key to its design is its reusable hardware and software operating system that performs all of its diagnostics programs.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 80
Application examples are: manufacturing testing with an emphasis on checking assembly-related issues and optimizing for time end-user targeted diagnostics, with an easy to comprehend non-technical presentation, and an emphasis on solutions service/warranty testing, focusing on identifying a failed or marginal field-replaceable unit (FRU) refurbishing centric, which attempts to determine if a system can be resold or reused, with an emphasis on depth of testing, at a cost to time spent testing Knowledge-Driven diagnostic system (such as a technician or diagnostician) where the knowledge acquired over time is used as a "mental model" of the system's operation and informs the diagnostic system through logical reasoning to one or more possible or likely causes for a situation to exist.
Example Diagnostics Program Applications A BIOS embedded Power-on self-test (POST) program that validates integrity of the system's hardware components before commencing normal operation. Diagnostics that are run on- demand when a user needs assistance, typically within the primary operating system of the computer (e.g. Windows). "Off-line diagnostics" that are run outside the primary operating system, typically to reduce the masking influence of software on hardware issues
Household refrigerators that display diagnostics of their internal temperature, ice machine functionality, etc. The 1996 Onboard Diagnostics II system (OBD II) that standardized the diagnostics port across all models of cars and light trucks allowing vehicle owners and repair technicians access to the vehicle's error code and emissions history.
Personal computer users have diagnostics options from both software and hardware sources, e.g., Hewlett-Packard's (HP's) diagnostics guide for confirming hardware failures. Industrial production test equipment that diagnoses electronic devices or systems. When an electronic device such as a Bop It says it's version number such as "one point three six" and starts playing through a set of sounds one after the other.
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AC 5 he resolution ensures that the problem causes and resolutions are documented according to industry recommended T practice. The diagnostic tools which were used to resolve the problem must be documented on the service checklist for audit purposes as well as for future use.
Five Best Computer Diagnostic Tools Computer diagnostics tools are pieces of software that give you the knowledge you need to be able to potentially repair your own computer. Some of these tools come built in to your operating system while others come from 3rd party software developers. Either way, these tools help save you time and money.
Computer diagnostic tools can be used scan your computer’s hard drive, check your ram for errors, check cpu temp and give you information about any other devices connected to your computer. These tools are made to find problems that may be disrupting your computer’s normal performance. Once a problem is found, you can then plan your repair.
#1 Windows Performance Monitor The first one on our list is built right in to Windows operating systems. The performance monitor gives you a quick view of vital information related your computer’s hardware. From here, you can check out your CPU, Memory, Disk info and Ethernet information. You can use Performance Monitor to examine the effects of your running applications in both real time and by collecting data to check out for later analysis.
#2 Windows Resource Monitor Windows Resource Monitor is number two on our list. This diagnostic tool is more robust that Windows Performance Monitor. It is better suited for tracking individual aspects of CPU, Network, and memory and disk usage. This tool gives you an in depth look at what processes are affecting your CPU, how much memory is being used what is using it, individual process disk activity and network information like current TCP connections and what processes are listening on what port.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 82
#3 Open Hardware Monitor Open Hardware Monitor is a free open source application that runs on Windows and Linux systems. This diagnostic tool monitors your computers temperature sensors, fan speeds, voltages, load and clock speeds. If your computer is shutting down by itself, hanging or crashing, this tool can come in real handy by telling you that your system is overheating or the fans aren’t working properly.
#4 Speccy Speccy is another great computer diagnostic tool. This application gives information on just about everything including software, hardware, peripherals, disk info, graphics & network data. It’s easy to use layout make troubleshooting and maintenance a breeze. Great application to start with when you are looking for specific info about your computer.
#5 HD Tune HD Tune Pro is a great tool for HDD and SSD diagnostics. This utility allows you to benchmark your storage device showing you the minimum, maximum and average transfer rates along with many other useful tools. The other features of HD Tune include detailed drive info, error scanning, & drive health. The pro version allows you to check the health status of multiple drives, offers folder usage info, secure erase, file benchmark, disk monitor, cache test & extra tests.
Computer diagnostics are meant to serve a vital purpose. They are important tools which work automatically, with very little effort necessary from the end user. They help you discover and fix problems within your hard disks and network configurations. Rather than manually searching for small, hard-to-find problems on your own, you can simply allow computer diagnostics tools to take care of your problems for you!
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 83
Maintain a multi-user networked operating system Time: 120 minutes Activity: Self and Group
AC 1 he maintenance ensures that any configurations made to the multi-user networked operating system are in accordance with organisation requirements T Organisational requirements for maintenance includes Security; Integrity; Backups; Performance factors. The operating system is the physical environment where your application runs. Any vulnerability in the operating system could compromise the security of the application. By securing the operating system, you make the environment stable, control access to resources, and control external access to the environment.
The physical security of the system is essential. Threats can come through the Web, but they can also come from a physical terminal. Even if the Web access is very secure, if an attacker obtains physical access to a server, breaking into a system is much easier. Review security policies and recommendations for your operating system. Consider implementing the following security best practices.
User Accounts Limit the number of user accounts on the server computers. Unnecessary and legacy user accounts increase system complexity and may present system vulnerabilities. Fewer user accounts reduces the amount of time administrators spend on account administration. Ensure that only a few trusted users have administrative access to the server computers. Fewer administrators make it easier to maintain accountability. The administrators must be competent. Assign the minimum required access permissions for the account that runs the application. If attackers obtain access to the application, they have the permissions of the user who runs the application.
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Account Policies Develop and administer password policies that promote operating system security. Examples of such policies are the strong password rule and the password change schedule. Test the strength of users' passwords by breaking the passwords. The users who do not comply with the strong password rule receive a notification to update their passwords according to the organization password policy. Software is available to help you with this task. On a UNIX operating system, activate the shadow password file. On UNIX, passwords are stored in the /etc/passwd file. This file is open to everyone, which presents a security risk. To enhance password security, activate the shadow password file named /etc/shadow. If this file is available, passwords are stored in it instead of the passwd file. Because permissions for the /etc/shadow file are more restrictive, the security risk is lower.
File System Grant the users read-only permissions for required directories. If attackers obtain access to an application, they have the user permissions.
Deny access by default. Access to resources is denied for everyone except for the users to whom access is granted explicitly. You can deny read and write permissions for all directory structures for all users. Only users to whom these permissions are granted explicitly have access to the directories and files. This policy also protects any resources that were overlooked by an administrator.
Network Services Provide the minimum number of required services on the server computer. Use only the services that you need to run the application. Each service is a potential entry point for a malicious attack. Reducing the number of running services also makes your system more manageable. For example, you may not need the ftp, rlogin, or ssh services. Reduce the level of access permissions for the network services users. Network services are exposed to the public.
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Ensure that the user accounts that have access to the Web server do not have access to the shell functions. Ensure that unused services do not exist in the rc files, rc0 through to rc6, in the /etc directory on UNIX and Linux operating systems. Ensure that unused services are not running, and that they do not start automatically on Microsoft Windows operating systems. Ensure that required services are running on UNIX.
You can use the ps and netstat utilities to see the running services. The ps utility gives a list of processes currently running on the computer. The netstat utility provides a list of ports that are currently in use. Reduce the number of trusted ports specified in the /etc/services file. Delete or comment out the ports that you do not plan to use to eliminate possible entry points to the system. Protect your system against NetBIOS threats associated with ports 137, 138, and 139. These ports are listed in the /etc/services file. Use wrapper services, such as iptables. Ensure that the services are current by checking often for security updates. Avoid using services that have a graphical user interface (GUI), if possible. Such services introduce many known security vulnerabilities.
System Patches Run the latest, vendor-recommended patches for the operating system. The patches may be core OS patches, or patches required by additional applications. Schedule regular maintenance of security patches. Operating System Minimization Remove nonessential applications to reduce possible system vulnerabilities. Restrict local services to the services required for operation. Implement protection for buffer overflow. You may need third-party software to do this.
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Logging and Monitoring Log security-related events, including successful and failed logons, logoffs, and changes to user permissions. Monitor system log files. Use a time server to correlate time for forensics. Secure the system log files by restricting access permissions to them. Logs are important for daily maintenance and as a disaster recovery tool. Therefore, they must be protected from system failures and user tampering. Use IPF logging to build a more sophisticated logging system.
To increase the security of the log file system, you can place all log files in one location, on one server This simplifies the administration of log files. set up multiple logging servers for redundancy use a remote server for logging This protects the logs if the system is compromised and, for example, the hard drive is destroyed. Because an IPF server is accessed through the network, it can be located anywhere in the world. Secure the logging configuration file. The configuration file contains settings that, if changed, can compromise the reliability of the log system. For example, setting the log level incorrectly may cause some failures not to be logged. Enable logging of access requests on the Web server. This can be useful in identifying malicious activity.
System Integrity Build production systems from a known and repeatable process to ensure the system integrity. Check systems periodically against snapshots of the original system. Use available third-party auditing software to check the system integrity. Back up the system resources on a regular basis.
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AC 2 he maintenance ensures that changes to the multi-user networked operating system maintain the integrity and security of T the software Multi-user operating systems are designed to have multiple terminals (monitor, keyboard, mouse, etc.) all connected to a single mainframe (a powerful CPU with many microprocessors) that allocates time for each user's processing demands so that it appears to the users that they are all working simultaneously.
Resource allocation: a system for dividing computing resources among multiple, competing requests so that each request is eventually fulfilled. System: a computer's combination of hardware and software resources that must be managed by the operating system. Terminals: a set of basic input devices, such as a keyboard, mouse, and monitor that are used to connect to a computer running a multi-user operating system. Time-sharing: a strategy used by multi-user operating systems to work on multiple user requests by switching between tasks in very small intervals of time.
Multi-user operating systems A computer's operating system (OS) is its most fundamental type of software. It manages the computer system (its hardware and other installed software). An OS is often described as the computer's “traffic cop.”
It regulates how the different parts of the computer can be used and which users or devices may use them. Many OS functions are invisible to the user of the computer. This is either because they occur automatically or because they happen at such a low level, as with memory management and disk formatting.
A multi-user OS performs the same types of operations as a single-user OS. However, it responds to requests from more than one user at a time. When computers were first developed, they were huge, complex machines that took up a great deal of physical space. Some of the first computers took up whole rooms and required several people to spend hours programming them to solve even simple calculations. These origins shaped the way that people thought about how a computer should work.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 88
Computers became more powerful and able to handle more and more complex calculations in shorter time periods. However, computer scientists continued to think of a computer as a centralized machine usable by more than one person at a time through multiple terminals connected by networking.
This is why some of the earliest OSs developed, such as UNIX, were designed with a multiterminal configuration in mind. Given the nature of early computers, it made more sense to share access to a single computer. Only years later, when technology advanced and PCs became widely available and affordable, would the focus switch to single-user OSs.
Shared computing One example of a multi-user OS is the software used to run the servers that support most webmail applications. These systems have millions or even billions of users who continually log on to check their messages, so they require OSs that can handle large numbers of users at once. A typical webmail application might require hundreds of computers, each running a multi-user OS capable of supporting thousands of users at once.
Economy of scale Many companies are moving back toward the use of multi-user OSs in an effort to contain costs. For a large organization to purchase and maintain full featured computers for each employee, there must be a sizable investment in personnel and computer hardware. Companies seeking to avoid such expense find that it can be much more cost effective to deploy minimally equipped terminals for most users.
This allows them to connect to servers running multi-user OSs. Backing up user data is also simpler with a multiuser OS because all of the data to be backed up is on the same machine. Therefore, it is less likely that users will lose their data and it saves time and money for the organization.
Module 4 – Operating system support skills Author: LEARNER MANUAL Rel Date: 27/01/2018 Rev Date: 01/06/2023 Doc Ref: 48573 LM Mod 4 v-1 PAGE 89
AC 3 he maintenance ensures that monitoring and tuning of the system maximises operation and performance, and meets manufacturer and organisation T specifications. Monitoring the performance of operating systems and processes is essential to debug processes and systems, effectively manage system resources, making system decisions, and evaluating and examining systems. These tools are primarily divided into two main categories: real time and log-based.
Real time monitoring tools are concerned with measuring the current system state and provide up to date information about the system performance. Log-based monitoring tools record system performance information for post-processing and analysis and to find trends in the system performance.
Introduction Computer operating systems monitor their resources constantly. In a system, processes are the main resource owners, and as such, most monitoring is done at the process level. This information is used by operating systems while they are running to perform effective memory management, scheduling, multiprogramming, and many other important decisions.
In addition, performance monitoring is useful while developing and refining systems, and it provides user support during everyday operation. Records of operating system and process performance can be used to quantify changes to the system and allow accurate comparisons to other systems. They can also be used to predict the performance of similar systems and what type of performance gains may be expected in the future.
There are a large number of operating system and process monitoring tools available. This paper will present a survey of some of the most common tools used for operating system and process monitoring. These tools are primarily divided into two main categories: real time and log-based.
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Real time monitoring tools are concerned with measuring the current system state and provide up to date information about the system performance. Log-based monitoring tools record system performance information for post-processing and analysis and to find trends in the system performance. In addition to these categories, this survey will look at Windows- based tools and Unix-based tools, since the tools are very different for these two common operating system types.
Real Time Performance Monitoring Tools Real Time Monitoring Tools are concerned with monitoring and displaying the current system performance. They sum up the performance for a particular factor with a single number. Typically, these tools rely on system calls that are built into the operating system to extract the performance readings. Because these calls are built into the operating system, they do affect the system performance, sometimes significantly.
They are also very difficult to change since the operating system source code is not usually readily available. I will describe a number of the most common operating system and process performance monitoring tools for Windows and Unix systems in the following sections.
Windows-Based Tools In this section, I will examine real time operating system and process monitoring tools for Windows systems.
Task Manager (taskmgr) Task Manager is probably the most well-known tool for monitoring processes on the Windows operating system. Task Manager was introduced with Windows NT and provides a fast look into the current system state. It shows all applications (one or more processes running within a single application context) and their state, all processes and some of their most frequently used performance measures, and some general system performance measurements.
Newer versions also display networking performance measurements. All measurements are made by directly calling functions in the operating system to retrieve system counters. In addition, Task Manager gives users the ability to control the system by affecting the running process. This is the function general computer users typically use Task Manager for when an application or process enters a "hung" state due to errors in the code and cannot be exited normally or when a process is hogging the CPU.
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In addition to ending a process, Task Manager also allows users to end a process tree killing all threads associated with the selected process, set a process's priority to reduce or increase its CPU consumption, and set a processes affinity to certain CPUs to control which CPUs a process will execute on in a multi-CPU system.
Two of Task Manager's tabs present operating system performance data to the user. The first is the Processes tab, shown in Figure 1. The Processes tab shows the current memory and percentage of CPU usage of every process running on the computer as well as the total CPU and memory usage of the system. While this is not a lot of information, it is a very good first indicator when a process is taking too much of the CPU or has a memory leak. It is easy to use and even allows sorting by name, user name, CPU usage, or memory usage.
The second Task Manager tab that presents operating system performance data is, not surprisingly, the Performance tab, shown in Figure 2. The Performance tab in Task Manager provides a top level view of the system state in terms of CPU and memory usage. A short history is shown on a graph, but once again, none of this data is logged for comprehensive analysis.
Task Manager's data is updated every one second by default, but it can be changed to one of three preset values or set to only update manually. It is highly integrated into the operating system, and it is not designed to log any of its performance measures for performance analysis or system evaluation [Moore]. However, it is an invaluable tool in monitoring and adjusting the processes running on a computer. Task Manager is also the standard for real time operating system and process monitoring tools for Windows systems that all other tools must be evaluated against, because another tool must provide some features not available in Task Manager for it to be considered useful.
Performance Monitor (perfmon) Performance Monitor is the second most common operating system performance monitoring tool for Windows. Performance Monitor acts as both a real time and log-based performance monitoring tool for operating systems, so only the real time portion of the tool will be discussed in detail in this section, and the logging portion will be discussed later.
Like Task Manager, Performance Monitor measures performance by making system calls to retrieve system counters, but Performance Monitor makes these calls via a performance library that also supports logging of the counters.
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Unlike Task Manager, Performance Monitor provides an interface to monitor any selection of a huge set of system counters on a graph in real time, rather than just the limited set Task Manager uses. Counters include things like percentage of processor time, thread count, page fault rate, memory size, and elapsed time for processes.
Similarly, there are counters that provide state for threads, the processor, the system, network interfaces, memory, physical disks, and many others. This level of detailed information available for monitoring from Performance Monitor is very extensive and makes Performance Monitor ideal for monitoring resource usage and performance of almost all pieces of a Windows system.
The main window for Performance Monitor, shown in Figure 3, is a graph of all selected system counters updated in real time at a specified rate. Almost everything on this display is customizable from whether it is a graph or a histogram to the colours assigned to certain counters.
The current reading and statistical information is displayed for the selected counter as the graph updates. Only one counter can be selected at a time for displaying numerical data, but any number of counters can be included on the graph at once.
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You are now ready to go through a check list. Be honest with yourself
Tick the box with either a √ or an X to indicate your response
□ I am able to plan the installation of system software for a multi-user networked operating system.
□ I am able to install a multi-user networked operating system
□ I am able configure a multi-user networked operating system
□ I am able to test the installation and configuration of a multi-user networked operating
□ I am able to Monitor the performance of a multi-user networked operating system
You must think about any point you could not tick. Write this down as a goal. Decide on a plan of action to achieve these goals. Regularly review these goals.
My Goals and Planning: ______
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