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For ten years researchers have been attempting to construct programming language systems that support orthogonal persistence above conventional operating systems. This approach has proven to be poor; researchers invariably construct a complete abstract machine above the operating system with resulting loss of efficiency. This paper describes a new approach, the construction of an operating system designed to support orthogonal persistence.
The operating system, Grasshopper, relies upon three powerful and orthogonal abstractions: containers, loci and capabilities. Containers provide the only abstraction over storage, loci are the agents of change, and capabilities are the means of access and protection in the system. This paper describes these three fundamental abstractions of Grasshopper, their rationale and how they are used. The aim of the Grasshopper project is to construct an operating system that supports orthogonal persistence ...
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hi...plz send the ppt and seminar reports for the topics
1 grasshopper operating system
2 graphical virtual perception processor
in my email
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more information about GRASSHOPPER Operating System
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Hi,
visit this thread for getting the full report of grasshopper operating system:
http://studentbank.in/report-grasshopper...ull-report
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hai sir i need the complete ppt of grass hopper operating system
can you kindly...help me in this matter
yours faithfully
greeshma
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why the name grasshopper operating system
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[attachment=13485]
Grasshopper Operating system
What is ?
Why ?
Grasshopper is an operating system that is being developed as a joint effort by University of Sydney and University of Stirling . Two professors (John Rosenberg - University of Sydney and Alan Dearle - University of Stirling) together with three graduate assistants (David Hulse,Anders Lindstorm and Stephen Norris) are working on Grasshopper
It is not only an OS but also an OS that supports orthogonal persistence.
Grasshopper relies upon three powerful abstractions, Containers, Loci and capabilities.
Most existing operating systems suffer from the discontinuity between permanent and temporary data, lack of resilience to failure.
In conventional OS’s permanent data must be accessed via the files system and it is not consistent with data in the virtual memory.
Resilience of data and computations is essential for many applications.
That where Grasshopper comes in. - Orthogonal Persistence and resilience.
What is Orthogonal Persistence?
In 1981, Atkinson proposed that all data in a system should persist for as long as they are required. He called the aspect of longetivity Persistence.
He also proposed that all the data should be treated uniformly regardless of the length of time it has persisted, that is, the persistence of data is orthogonal to its other attributes size, type and ownership.
Orthogonal Persistence has two principles
Data may persist for as long or a short as it is required
the objects are manipulated in the same manner regardless of the time they have persisted.
Architecture of Grasshopper
Relies on three basic abstractions -
Containers
It provide the only abstraction of storage space.
Loci
Loci are the agents of change. They include processes and threads.
Capabilities
Capabilities are the means of access and protection in the system.
Containers
Containers are the single abstraction over storage. They eliminate the need for the file system and address space.
In orthogonal persistent systems, using container eliminate the need for programmers to know the location of data. This means that whether data is in RAM or backing storage, the programmer perceives no difference.
This raises the question of addressing in orthogonal systems. There there models employed.
Single flat address space
Single partitioned address space
Fully partitioned address space.
More containers
Single flat address space
This is similar to conventional OS’s. In this model all data resides in a single address space with no structure imposed.
There is a limitation on the size of address space. But with the advent of 64 bit address spaces, this is possible.
Single partitioned address space
The idea of a large address space is retained. However, this address space is partitioned into semi independent regions. These regions contain logically related set of data.
Fully partitioned address space
The store is fully partitioned with each address being treated as an instance of the flat address space.
Container Mapping
Loci
Loci are the agents of change in the Grasshopper. These are processes.
In the simplest form, they are the content of the registers.
Each loci is associated with a host container. The locus executes in only one container (host container)at time but can move from container to container. This is done by locus invocation.
There are two methods of interactions between entities in an operating system.
Message Oriented
Procedure Oriented.
Capabilities
Capabilities provide inter process(container) communications. Each container and loci contains a list of capabilities.
The list consists of unique key(name), the operations which that container and loci are allowed to perform in a system.
When code executed by a locus call for the manipulation of another object, a list of capabilities must be presented. This identifies the calling objects and the operations it is allowed to perform.
More capabilities
The only way an operation can be performed is by that operation providing a valid capability.
Capabilities derive their power from two points
Names are unique
Capabilities cannot be forged.
They are created and modified by the system in controlled manner.
Data Management
Of great importance in Grasshopper is how to give loci direct access to data and provide resilience and recovery.
At present the container abstraction is implemented using user level entities called container managers.
Grasshopper kernel implements 3 ADTs that allow the container abstraction to work.
Disks – allow container managers to access physical disks
Physical page sets – allow for memory manipulation
Local container Descriptors (LCDs) – are used to store address translation information such as the correspondence between virtual and physical address.
Advantages
Direct hardware access.
Easy and complete memory use.
It is simpler and less error-prone programs.
Disadvantages
Unrestricted access.
No backup is available.
Memory loss dead locks preemptions so on.
Conclusions
Grasshopper satisfies the four principle requirements of orthogonal
persistence namely:
i. support for persistent objects as the basic abstraction, ii. the reliable and transparent transition of data between long and
short term memory,
iii. persistent processes and
iv. control over access to objects. This is achieved through the provision of three powerful and orthogonal abstractions namely containers, loci and capabilities. Containers provide the only abstraction over storage, loci are the agents of change, and capabilities are the means of access and protection in the system. These abstractions are supported by a fourth mechanism, the manager, which is responsible for data held in a container.
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hai sir i need the complete ppt and report of grass hopper operating system
can you kindly...help me in this matter
yours faithfully
neha
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sir plzzzzzzzz kindly mail me the block diagram of this project.
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please mail grasshopper operating system ppd,doc
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please give grasshopper operating system report
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please mail grasshopper operating system pdf doc and ppt
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Hi friend refer the page link for more details (PPT) on GRASSHOPPER Operating System
http://studentbank.in/report-grasshopper...tem?page=2
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