Slides of a course that is given to teach embedded linux to engineers. The full course is 2-days; this is the first time a 'light' version was given lasting a single day.
Focus is on
. What is Linux
. How do I compile
. How do I flash
Linux has become integral part of Embedded systems. This three part presentation gives deeper perspective of Linux from system programming perspective. Stating with basics of Linux it goes on till advanced aspects like thread and IPC programming.
Basics of Operating Systems Definition – Generations of Operating systems – Types of Operating Systems, OS Service, System Calls, OS structure: Layered, Monolithic, Microkernel Operating Systems – Concept of Virtual Machine
The second part of Linux Internals covers system calls, process subsystem and inter process communication mechanisms. Understanding these services provided by Linux are essential for embedded systems engineer.
Slides of a course that is given to teach embedded linux to engineers. The full course is 2-days; this is the first time a 'light' version was given lasting a single day.
Focus is on
. What is Linux
. How do I compile
. How do I flash
Linux has become integral part of Embedded systems. This three part presentation gives deeper perspective of Linux from system programming perspective. Stating with basics of Linux it goes on till advanced aspects like thread and IPC programming.
Basics of Operating Systems Definition – Generations of Operating systems – Types of Operating Systems, OS Service, System Calls, OS structure: Layered, Monolithic, Microkernel Operating Systems – Concept of Virtual Machine
The second part of Linux Internals covers system calls, process subsystem and inter process communication mechanisms. Understanding these services provided by Linux are essential for embedded systems engineer.
This course gets you started with writing device drivers in Linux by providing real time hardware exposure. Equip you with real-time tools, debugging techniques and industry usage in a hands-on manner. Dedicated hardware by Emertxe's device driver learning kit. Special focus on character and USB device drivers.
This presentation gives a brief over view of Embedded Systems. It describes the common characteristics of Embedded systems, the design metrics, processor technologies and also summarizes differences between Microcontrollers and Microprocessors.
Embedded Systems: Lecture 2: Introduction to Embedded SystemsAhmed El-Arabawy
This lecture provides an introduction to Embedded Systems and its applications. It also outlines some of the differences for developing embedded systems compared to traditional systems
-> Deep dive inside the kernel Interrupt management subsystem.
-> Entire presentation is oriented towards 8259 Interrupt controller.
-> Detail understanding of how request_irq() function works.
This course gets you started with writing device drivers in Linux by providing real time hardware exposure. Equip you with real-time tools, debugging techniques and industry usage in a hands-on manner. Dedicated hardware by Emertxe's device driver learning kit. Special focus on character and USB device drivers.
This presentation gives a brief over view of Embedded Systems. It describes the common characteristics of Embedded systems, the design metrics, processor technologies and also summarizes differences between Microcontrollers and Microprocessors.
Embedded Systems: Lecture 2: Introduction to Embedded SystemsAhmed El-Arabawy
This lecture provides an introduction to Embedded Systems and its applications. It also outlines some of the differences for developing embedded systems compared to traditional systems
-> Deep dive inside the kernel Interrupt management subsystem.
-> Entire presentation is oriented towards 8259 Interrupt controller.
-> Detail understanding of how request_irq() function works.
Yocto - Embedded Linux Distribution MakerSherif Mousa
Yocto is an Embedded Linux distribution maker.
This presentation is a quick start guide for Yocto buildsystem to get familiar with the tool and how to start building your own custom Linux system for a specific hardware target.
Building Mini Embedded Linux System for X86 ArchSherif Mousa
Full tutorial to learn how to build your own embedded Linux system as a MiniOS for your X86 device (PC ...).
It's considered a good start for anyone to get into the field of Embedded Linux building and development.
In a presentation for Atainz, Terry Baucher of Baucher Consulting (www.baucherconsulting.co.nz) explains how to handle an IRD Audit & what to do should the IRD come calling.
Baucher also goes into detail about the difference between an IRD Audit and an IRD Review and how each should be treated.
This presentation was given on behalf of Atainz in March 2013
10 ways hardware engineers can make software integration easierChris Simmonds
Sometimes it seems that hardware engineers go out of their way to may the job of software engineers difficult. Here are my top 10 tips (plus two bonus slides) that will make integration to smoothly
Operating Systems Structure1- Explain briefly why the objectives o.pdfrishabjain5053
Operating Systems Structure
1- Explain briefly why the objectives of a purely batch multiprogramming operating system
conflict with those of an interactive system.
2- What features from the Mainframe operating system Multics do we see in modern operating
systems?
Solution
Answer 2..
The various features of Multics are :
-Segmented memory
-Virtual memory
-High-level language implementation
-Shared memory multiprocessor
-Multi-language support
-Relational database
-Security
-On-line reconfiguration
-Software engineering
Out of the above features, the feature that are present in modern operating system are:
1) security
Each user has to be authenticated with an username and password (network and multi-user
operating system).
Their data and files will be kept private from other users, unless they choose to make some
shareable with others.
The operating system will only allow administrators (\'super users\') to change parts of the
operating system and install applications.
2)Segmented memory
To use shared memory, we have to perform 2 basic steps:
Request to the operating system a memory segment that can be shared between processes. The
user can create/destroy/open this memory
using a shared memory object: An object that represents memory that can be mapped
concurrently into the address space of more than one process..
Associate a part of that memory or the whole memory with the address space of the calling
process. The operating system looks for
a big enough memory address range in the calling process\' address space and marks that
address range as an special range. Changes in that address
range are automatically seen by other process that also have mapped the same shared memory
object.
3)Virtual memory
Virtual memory is a memory management capability of an OS that uses hardware and software
to allow a computer to compensate for physical memory
shortages by temporarily transferring data from random access memory (RAM) to disk storage.
Virtual address space is increased using active memory
in RAM and inactive memory in hard disk drives (HDDs) to form contiguous addresses that
hold both the application and its data.
4)Shared memory multiprocessor
Shared memory is the fastest interprocess communication mechanism. The operating system
maps a memory segment in
the address space of several processes, so that several processes can read and write in that
memory segment without
calling operating system functions. However, we need some kind of synchronization between
processes that read and write shared memory.
Consider what happens when a server process wants to send an HTML file to a client process
that resides in the same machine using network mechanisms:
The server must read the file to memory and pass it to the network functions, that copy that
memory to the OS\'s internal memory.
The client uses the network functions to copy the data from the OS\'s internal memory to its own
memory.
As we can see, there are two copies, one from memory to the network an.
How many total bits are required for a direct-mapped cache with 2048 .pdfEye2eyeopticians10
How many total bits are required for a direct-mapped cache with 2048 entries each holding an 8
word (of 32 bits or 4 bytes) block, assuming a 32-bit address? Discuss with the help of a diagram
the logic to check a hit or miss (that is, presence or absence) of a required memory block in the
cache described in 1(a), and access a specific word of the block in case of a hit. Label all the
fields in a cache word. What is virtual memory? What is the fundamental difference between the
memory hierarehy of Q.1 (a) and this one? Explain how briefly how it helps multiple users share
the limited memory, and still get the illusion of using a dedicated resource?
Solution
2. (a) Virtual Memory: In computing,virtual memoryis a memory management technique that is
implemented using both hardware and software. It mapsmemory addresses used by a program,
calledvirtual addresses, intophysical addressesin computer memory. Main storage as seen by a
process or task appears as a contiguous address space or collection of contiguous segments. The
operating system manages virtual address spaces and the assignment of real memory to virtual
memory. Address translation hardware in the CPU, often referred to as a memory management
unit orMMU, automatically translates virtual addresses to physical addresses. Software within
the operating system may extend these capabilities to provide a virtual address space that can
exceed the capacity of real memory and thus reference more memory than is physically present
in the computer.The primary benefits of virtual memory include freeing applications from having
to manage a shared memory space, increased security due to memory isolation, and being able to
conceptually use more memory than might be physically available, using the technique of
paging.
Virtual memory makes application programming easier by hiding fragmentation of physical
memory; by delegating to the kernel the burden of managing the memory hierarchy(eliminating
the need for the program to handle overlays explicitly); and, when each process is run in its own
dedicated address space, by obviating the need to relocate program code or to access memory
with relative addressing. Memory virtualization can be considered a generalization of the
concept of virtual memory.
Virtual memory is an integral part of a modern computer architecture; implementations require
hardware support, typically in the form of a memory management unit built into theCPU. While
not necessary, emulators and virtual machines can employ hardware support to increase
performance of their virtual memory implementations. Consequently, older operating systems,
such as those for the mainframes of the 1960s, and those for personal computers of the early to
mid-1980s (e.g. DOS), generally have no virtual memory functionality, though notable
exceptions for mainframes of the 1960s include:
and the operating system for the Apple Lisa is an example of a personal computer operating
system of the 1980s that features vir.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2. INTRODUCTION In case of embedded systems, the rise in processing speeds of embedded processors and microcontroller evolution has lead to the possibility of running computation and data intensive applications on small embedded devices that earlier only ran on desktop-class systems. From a memory stand point, there is a similar need for running larger and more data intensive applications on embedded devices.However, support for large memory address spaces, specifically, virtual memory, for MMU-less embedded systems is always lacking. But by implementing virtual memory scheme for MMU-less systems as a software , based on an application level virtual memory library and a virtual memory aware assembler. This type of implementation is open to programmer and always available for changes.
3. Many software developers in recent years have turned to Linux as their operating system of choice. Until the advent of uClinux developers of smaller embedded systems, usually incorporating microprocessors with no memory management unit could not take advantage of Linux in their designs. UClinux is a variant of mainstream Linux that runs on 'MMU-less' processor architectures. Component costs are of primary concern in embedded systems, which are typically required to be small and inexpensive. Microprocessors with on-chip memory management unit (MMU) hardware tend to be complex and expensive, and as such are not typically selected for small, simple embedded systems which do not require them. With many advantages of MMU less Systems (like : speed and cost efective ness) use of them is increasing day by day and a proper , stable and real time Operating system is required , and in this paper i am going to study this type of operating systems and schemes of implementing Virtual memory using software.
4.
5.
6.
7.
8.
9.
10. Memory Management and Memory Management Unit Memory management is the act of managing computer memory. In its simpler forms, this involves providing ways to allocate portions of memory to programs at their request, and freeing it for reuse when no longer needed. The management of main memory is critical to the computer system. A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware component responsible for handling accesses to memory requested by the central processing unit (CPU). Its functions include translation of virtual addresses to physical addresses (i.e.,virtual memory management ) , memory protection, cache control, bus arbitration etc.
11.
12. Why create an MMU-less Linux? Linux has become popular on embedded devices—especially consumer gadgets, telecom routers and switches, Internet appliances and automotive applications. Because of the modular nature of Linux, it is easy to slim down the operating environment by removing utility programs, tools, and other system services that are not needed in an embedded environment. Advantages of Linux is that it is a fully functional OS, with support for network that is becoming a very important requirement in embedded systems. We can add or unload modules from the kernel at runtime, this makes embedded Linux very flexible. It is more encouraging that the Linux code is widely available , portable to any processor, scalable and stable .
13.
14. Diagram Below shows the data flow towards target system , The application source code. Important is Application’s view of address space is as large as the secondary storage i.e., the virtual address space. The virtual memory library. This library consists of an implementation of virtual to physical address translation (vm.c). It also includes a header file (vm.h) with configurable parameters (page size, ram size etc.)
15.
16.
17.
18. Virtual Memory Approach Algorithm for Virtual to Physical memory Address Translation 1: function virtual-to-physical 2: Input va : virtual address, wr : 1 => write ;0 => read 3: Output pa : physical address 4: Decompose va into ( tag ; page ; off set ) 5: pte PTE [ page ] 6: if pte . tag = va . tag and pte . valid = 1 then 7: if wr = 1 then 8: pte : dirty 1 9: end if 10: return pa = page * sizeof ( page ) + offset 11: end if 12: if pte . valid = 1 and pte . dirty = 1 then 13: write RAM [ page ] to secondary store 14: end if 15: Read newpage | va (belongs to) newpage from secondary store 16: Update pte . tag, pte . page , pte . valid 17: if wr = 1 then 18: pte . dirty 1 19: end if 20: return pa = page * sizeof ( page ) + offset
19. Approach 1 - Pure VM In application every memory access is in a virtual address space which is translated to physical address during runtime using a predesigned algorithm. This is a transparent approach towards application where they access memory directly and have full control on it. Drwaback : When every memory address is virtualized algorithm(function) to change virtual address to physical address is called which is an extra load on the system.
20. Approach 2 - Fixed Address VM In this approach, a region of the memory is marked as virtualized. Any memory access (load/store) that belongs to this marked region is translated. This approach requires the programmer to indicate to the vm-assembler the region marked as virtual. As opposed to the previous approach, in this case, the overhead of translation from virtual to physical address is reduced to only the memory region marked as virtual. This however, requires a runtime check to be made at every load/store to determine if the address is virtualized.This is achieved by modifying the vm-assembler so that it inserts code that does runtime check on every memory access and translates only those addresses that are virtualized. In our experiments, we tested this approach by marking all the data region belonging to global variables as belonging to virtual address space.
21. Approach 3 - Selective VM Selective VM is similar to the previous approach, but is more fine-grained in terms of memory that is virtualized. Note that in the previous approach, a runtime check was required on every memory access to determine if the address is virtualized. Selective VM avoids this runtime check overhead by annotating data structures at source level. It requires the programmer to tag individual data structures as belonging to virtual address space (as opposed to an entire region). This annotation is done at variable declaration, using a #pragma directive. Any use or def of annotated data structure in the source is modified to a call to the virtual-to-physical function. This approach significantly reduces the runtime overhead by restricting the translation only to large data structures that can reap benefit out of virtualization. It gives the embedded programmer more control on what is virtualized. However, this approach is the least transparent to the application programmer compared to the other two approaches.
22.
23.
24. Future Perspective My future work will focus on optimizing the virtual to physical translation that can lead to reduction in execution time cycles. I had also planned to focus on considering additional caching techniques , such as associative schemes. I am also trying to find some way of implementing software MMU for normal systems (Laptops or Desktops) so that the interaction of Memory can be reduced and hence increase in the speed of the system.
25. Conclusion Right now my study is towards a software virtual memory scheme for MMU-less embedded systems. I am trying this using a vm-aware assembler and a virtual memory library.The virtual memory system that is presented can be customized by adjusting two configuration parameters, namely, RAM size and Page size. My future work will focus on optimizing this virtual memory implementation that can lead to reduction in execution time cycles. Also i want to extend and use this project for reducing the energy consuption for Systems contaning MMU (CPU's , Laptops and other Embedded Devices).
26.
Editor's Notes
The processor generated virtual address consists of B-bits (If the secondary storage is large enough, we could have B = N ). This address is broken down into offset ( K least significant bits), page ( M - K bits) and tag ( N - M bits). The page bits of virtual address point to an entry in the PTE. The virtual address tag bits are compared to the tag field of this PTE. If the valid bit is set and the tag bits match, we have a hit (i.e., the physical address is in main memory). The actual physical address is computed by concatenating offset bits of virtual address with “page” entry of the PTE. There can be cases other than a hit, depending on the result of comparing tags, valid bit and dirty bit. These are described in the virtual-to-physical translation algorithm. This algorithm is similar to a direct mapped address translation used in traditional operating systems. Note that the virtual memory library, mentioned in previous section, has the implementation of 1.