TiWorker is an EXE file (Window Modules Installer Worker (WMIW), as it appears in Task Manager). The Ti prefix stands for Trusted Installer. WMIW is part of Windows Update.
The interesting thing about TiWorker is that it often consumes significant disk (8.9MB/s or 10MB/s) and also has a large memory footprint (e.g. 200-250 MB). Experiences have been noted in the MS Community.
Windows Update Standalone Installer (wusa.exe) can be a problematic thing to fix. For starters, you won't see a listing for it in Task Manager's Startup section. It may also not visually consume too much memory by itself but stopping this process appears to have a knock-on effect on overall memory consumption.
wusa.exe is a feature of Windows 10 as well as legacy Windows versions including Windows 7, Vista and Windows Server 2008.
Azure Databricks is a data analytics platform optimized for Microsoft Azure. It uses the Apache Spark analytics engine.
UE-V refers to User Experience Virtualization. UE-V captures your desktop settings on a centrally managed file share. Personalized settings are applied to their work session when users log on, regardless of which device or VDI session they log into. UE-V is a feature of Windows 10 for Enterprise. A useful chart of UE-V components can be found here.
There are a number of distributing caching options in .NET.
Ignoring the distributed aspect of our desired cache for the minute we focus on the inbuilt MemoryCache.
For an in-process, in-memory cache, one option is to use MemoryCache (System.Runtime.Caching). Caching data types were introduced in .NET 4. A CacheItemPolicy dictates how long objects remain in the cache and what the eviction policy is.
Some more flexible and specialized options are:
Microsoft.Extensions.Caching.SqlServer
Windows Server 2022 is now in preview and is planned for release later in 2021. See this article from the Windows Server team. Note that one of the conditions of use is that you do not use a preview server in a production environment.
The new 2022 Server brings some Azure innovations on-premise.
This includes Azure Arc which aims at simplified management of hybrid and multi-cloud environments as well as Storage Migration Service which makes it easy to migrate data from older Windows Server installations to Azure or Windows Server 2019/2022.
The secured-core server is key to WS2022 design. This is a response to the rise in cyberattacks on servers targeted for ransomware attacks or bitcoin mining for example.
Firmware protection is one dimension of the security of the new design. There is evidence that ransomware platforms are adding firmware exploitation capabilities. There have been attacks e.g. on Active Directory Domain Controllers. DMA protection is one of the defence mechanisms utilized.
Virtualization based security (VBS) is one of the pillars of the secure-core server design. Features included such as Hypervisor-Protected Code Integrity (HVCI) - also part of Windows 10 (which has some known issues with device drivers).
ASP.NET Razor is a (server-side) markup language, that allows you to embed server-based code into web pages (Visual Basic and C#).
Razor syntax is similar to PHP and Classic ASP.
The following Razor code outputs a series of list items.
<ul>
@for (int i=0; i<5; i++) {
<li>@i</li>
}
</ul>
The foreach loop is of course also supported in Razor.
Managing state reliably in a distributed system is a challenge. Service Fabric rises to the challenge. The key hazards of a distributed system:
1. Messages can get lost
2. Failure of a node
3. Communication channel stalls
So when a stateful service needs to persist state, it must use a Reliable Collection! SF provides reliable Dictionaries and reliable Queues to serve this end.
Reliable data structures are distributed data structures but can be used as if they are local data structures.
Reliable collections are persisted by a Reliable State Manager component (which is represented by a class in the Microsoft.ServiceFabric.Data namespace which lives in the Microsoft.ServiceFabric.Data.dll in the Azure SDK).
The states are replicated by a Transactional Replicator to secondary replicas for availability and reliability.
Most stateful services inherit from a StatefulService class.
SMB 3.0 stands for Server Message Block 3.0. It was introduced in Windows Server 2012. Azure Files offers serverless file shares using the SMB 3.0 protocol.
When you create an Azure VM you are defaulted to have port 3389 open for inbound communication. This port is used by the Remote Desktop Protocol (RDP). All Windows boxes are by default RDP servers. They listen on TCP port 3389 and UDP port 3389.
An Ubuntu Server D2S in Azure will cost around $70 a month. This is the same for SUSE Linux, or Windows 10 Pro, or Windows Server 2019 Datacenter - Gen1, with 2 vCPUs and 8 Gb memory.
The Azure Portal is the place to manage your Azure subscription. Its URL is portal.azure.com.
The Av2 series of Azure VMs are suited for entry level workloads like Development and Test. Proof of concepts can be run Av2 series VMs.
The B-series of Azure VMs previewed in 2017.
They are adapted for bursty workloads such as web server that uses very little CPU until some particular request comes in.
While not utilizing the baseline performance of the CPU, the VM builds up credits.
When the VM builds up enough credits, you can burst your usage up to 100% of the vCPU for the period of time your application requires the higher CPU performance.
The B-series VMs are available in Windows and Linux variants.
There are quite variety of other types of VMs including DC series, designed to protect confidentiality and integrity of code and data.
To understand the architecture of Azure Service Fabric (or A18F) we must first be aware of, and understand, the subsystems underneath it.
First we consider the Transport Subsystem. This provides secure point-to-point communication channels within a Service Fabric cluster and between a Service Fabric cluster and its clients.
Then you have the Federation Subsystem. This forms the foundation of a unified cluster and comprises provision of failure detection, leader election and consistent routing.
The Reliability Subsystem is really important. This manages state replication, failover and load balancing; necessities in a highly reliable and available subsystem.
Recall:
1. Failover is when a request is redirected to an alternate server
2. Load balancing is about distributing request processing across multiple servers
The Management Subsystem relates to managing applications. It has services to manage application binaries; deploying, updating and deprovisioning applications and monitoring application health.
The Hosting Subsystem is responsible for managing application lifecycles on a cluster node.
The Communication Subsystem is actually strangely named. It is more of a "service discovery" subsystem. With workloads and infrastructure separated, services may migrate from host to host. The naming service provided by the communication subsystem allows clients to discover and connect to service instances.
The Testability Subsystem is perhaps the most interesting. It can simulate various failure scenarios to help developers find and address design and implementation deficiencies
Azure Service Fabric is Microsoft's Platform-as-a-Service (PaaS) offering for developers looking to host scalable and highly available distributed systems.
Microsoft has used it for years to support:
Skype for Business | Cortana | Intune (a cloud-based MDM -> Mobile Device Management | Azure Cosmos DB amongst other things.
ASF was open-sourced in March 2018.
Azure pipelines are being used all over the place, including Project Mu. The core documentation is here.
Microsoft Compatibility Telemetry is a Windows 10 service sending technical data to Microsoft periodically. It is one of the "disk killers" in Windows 10 (services that contribute to sending your disk usage to 100%). You can find and disable it in Task Scheduler, under:
Microsoft\Windows\Application Experience
You may be surprised also to find multiple triggers which activate telemetry collation and delivery to Microsoft on a regular basis. To turn it off, end the task and disable it from the Actions window.
A great source of insights into Azure Service Fabric (ASF) is the book "Programming Microsoft Azure Service Fabric" (or "Programming ASF or "PASF") by Haishi Bai.
Haishi is a principal software engineer at Microsoft.
The problem of leader election in distributed computing is one of the motivating problem statements that led to the development of ASF. This is the selection of a unique node in a series of nodes to co-ordinate a task. The algorithm details depend on the connection topology of the nodes e.g. rings, hypercubes etc.
Why is leader election an interesting topic in distributed systems?
Distributed systems may experience network outages or process failures. Consequently a leader node may cease to be the leader in a particular scenario.
To solve this problem, many solutions employ a heartbeat or polling method, so nodes are assured of the presence of the leader. When that leader terminates unexpectedly the nodes must elect a new leader.
Some options are:
1. Node with lowest process ID becomes the leader/
2. Race to acquire a shared distributed mutex. One caveat here is if the leader terminates, the mutex must be released.
3. Apply a leader election algorithm such as the Bully Algorithm or Ring Algorithm.
Containers and Linux support are newer parts of ASF.
GLB files are binary version of the GL (Graphics Language) transmission format (glTF) file which uses JSON encoding. Its creators (Khronos Group) have called it the "JPEG of 3D". For a good source of news on Khronos check out its twitter feed.
UEFI is the Unified Extensible Firmware Interface.
It is a specification for a software program to connect a computer's firmware to its operating system. Its origins came from Intel's Itanium days (64 bit microprocessor family launched in 2001, originally known as IA-64, with clock speeds ranging from 733MHz to 2.66GHz), where BIOS was found to be too restrictive for the larger server platforms being targeted by Itanium. It was then called Intel Boot Initiative and later EFI or Extensible Firmware Interface.
The first open source implementation of UEFI was released by Intel in 2004 and named Tiano. In December 2018, Microsoft forked Tiano and created Project Mu.
UEFI is expected to eventually replace BIOS.
If you have tinkered with Settings in Windows 10 you may be familiar with TPM. Even if not, read on. TPM, or Trusted Platform Module, is an ISO standard (ISO/IEC 11889) for a secure cryptoprocessor, which can execute cryptographic operations on a chip and includes some level of tamper-resistance. TPM was developed by a consortium founded in 2003 called the Trusted Computing Group (who maintain over 90 specifications aimed at building trusted computing environments).
