The Great Symbian

Operating Systems can be explored from two viewpoints: the user and the system.

USER VIEW
The user view of the computer varies by the interface being used. Most computer users sit in front of a PC, consisting of a monitor, keyboard, mouse and system unit. Such a system is designed for one user to monopolize its resources, to maximize the work that the user is performing. In this case,the operating system is designed mostly for ease of use, with some attention paid to performance, and none paid to resource utilization.

Some users sit at a terminal connected to a mainframe or minicomputer. Other users are accessing the same computer through other terminals. These users share resources and may exchange information. The operating system is designed to maximize resource utilization.

Other users sit at workstations, connected to networks of other workstations and servers. These users have dedicated resources at their disposal, but they also share resources such as networking and servers.

Recently, many varieties of handheld computers have come into fashion. These devices are mostly standalone, used singly by individual users. Some are connected to networks, either directly by wire or through wireless modems. Due to power and interface limitations they perform relatively few remote operations. These operating systems are designed mostly for individual usability, but performance per amount of battery life is important as well.

Some computers have little or no user view. For example, embedded computers in home devices and automobiles may have numeric keypad, and may turn indicator lights on or off to show status, but mostly they and their operating systems are designed to run without user intervention.

SYSTEM VIEW

We can view an operating system as a resource allocator. A computer system has many resources - hardware and software - that may be required to solve a problem. The operating system acts as the manager of these resources.

An operating system can also be viewed as a control program that manages the execution of user programs to prevent errors and improper use of the computer. It is especially concerned with the operation and control of I/O devices.

We have no universally accepted definition of what is part of the operating system. A simple viewpoint is that it includes everything a vendor ships when you order “the operating system”.

A more common definition is that the operating system is the one program running at all times on the computer (usually called the kernel), with all else being application programs. This is the one that we generally follow.

CLIENT-SERVER

-> System or networking is a distributed application architecture that partitions tasks or work loads between service providers (servers) and service requesters, called clients.[1] Often clients and servers operate over a computer network on separate hardware. A server is a high-performance host that is a registering unit and shares its resources with clients. A client does not share any of its resources, but requests a server's content or service function. Clients therefore initiate communication sessions with servers which await (listen to) incoming requests.

-> Client-server describes the relationship between two computer programs in which one program, the client program, makes a service request to another, the server program. Standard networked functions such as email exchange, web access and database access, are based on the client-server model. For example, a web browser is a client program at the user computer that may access information at any web server in the world. To check your bank account from your computer, a web browser client program in your computer forwards your request to a web server program at the bank. That program may in turn forward the request to its own database client program that sends a request to a database server at another bank computer to retrieve your account balance. The balance is returned to the bank database client, which in turn serves it back to the web browser client in your personal computer, which displays the information for you.

A server based network (i.e: not peer-to-peer):

PEER-TO-PEER SYSTEM

-> Peer-to-peer (P2P) system or networking is a method of delivering computer network services in which the participants share a portion of their own resources, such as processing power, disk storage, network bandwidth, printing facilities. Such resources are provided directly to other participants without intermediary network hosts or servers.[1] Peer-to-peer network participants are providers and consumers of network services simultaneously, which contrasts with other service models, such as traditional client-server computing.

SYMMETRIC MULTIPROCESSING

- In computing, symmetric multiprocessing or SMP involves a multiprocessor computer-architecture where two or more identical processors can connect to a single shared main memory. Most common multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors.
SMP systems allow any processor to work on any task no matter where the data for that task are located in memory; with proper operating system support, SMP systems can easily move tasks between processors to balance the workload efficiently.

ASSYMETRIC MULTIPROCESSING

- Asymmetric multiprocessing or ASMP is a type of multiprocessing supported in DEC's VMS V.3 as well as a number of older systems including TOPS-10 and OS-360. It varies greatly from the standard processing model that we see in personal computers today. Due to the complexity and unique nature of this architecture, it was not adopted by many vendors or programmers during its brief stint between 1970 - 1980.
Where as a symmetric multiprocessor or SMP treats all of the processing elements in the system identically, an ASMP system assigns certain tasks only to certain processors. In particular, only one processor may be responsible for fielding all of the interrupts in the system or perhaps even performing all of the I/O in the system. This makes the design of the I/O system much simpler, although it tends to limit the ultimate performance of the system. Graphics cards, physics cards and cryptographic accelerators which are subordinate to a CPU in modern computers can be considered a form of asymmetric multiprocessing.[citation needed] SMP is extremely common in the modern computing world, when people refer to "multi core" or "multi processing" they are most commonly referring to SMP.

OPERATING SYSTEM

- (commonly abbreviated to either OS or O/S) is an interface between hardware and user; it is responsible for the management and coordination of activities and the sharing of the resources of the computer. The operating system acts as a host for computing applications that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. This relieves application programs from having to manage these details and makes it easier to write applications. Almost all computers (including handheld computers, desktop computers, supercomputers, video game consoles) as well as some robots, domestic appliances (dishwashers, washing machines), and portable media players use an operating system of some type. [1] Some of the oldest models may however use an embedded operating system, that may be contained on a compact disk or other data storage device.

GOALS OF THE OPERATING SYSTEM:

It is easier to define an operating system by what it does than what it is, but even this can be tricky. The primary goal of some operating system is convenience for the user. The primary goal of other operating system is efficient operation of the computer system. Operating systems and computer architecture have influenced each other a great deal. To facilitate the use of the hardware, researchers developed operating systems. Users of the operating systems then proposed changes in hardware design to simplify them. In this short historical review, notice how identification of operating-system problems led to the introduction of new hardware features.

PARALLEL SYSTEMS

- Multiprocessor systems with more than one CPU in close communication.

- Tightly coupled system – processors share memory and aclock; communication usually takes place through the shared memory.

- Symmetric multiprocessing (SMP)

·Each processor runs and identical copy of the operating system.

·Many processes can run at once without performance deterioration.

·Most modern operating systems support SMP

- Asymmetric multiprocessing

·Each processor is assigned a specific task; master processor schedules and allocated work to slave processors.

· More common in extremely large systems

Advantages of parallel system:

1. Increased throughput

2. Economical

3. Increased reliability

3.1. graceful

3.2. degradationfail-soft systems

Questions to be answered.

1. What is the reason for technicians to wear special wrist grounding straps?

The safety wrist strap with grounding cord (integrated 1 MOhmresistor) for the derivation of electrostatic charges, which canadhere to persons at ESD work stations. The strap guaranteesconstant earthing and therefore avoids electrostatic charging atpersons. An ungrounded person causes capacity changes whenmoving, which could lead to spikes at worst case. Those spikesagain are able to damage or destroy electronic componentsNormally dangerous body voltages which may destroy electro-nic components are derivated when a person touches conducti-ve table covering. Charging caused by insulating floors, cloth andchair seats also have to be discharged. Furthermore there is nopermanent contact to the floor when the person is sittingTherefore an additional earthing via wrist strap is necessary.

2. After installing a new computer component why is it important to obtain the most current driver for it?

A device driver is a program that controls a particular type of device that is attached to your computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and so on. When you buy an operating system, many device drivers are built into the product. However, if you later buy a new type of device that the operating system didn't anticipate, you'll have to install the new device driver. A device driver essentially converts the more general input/output instructions of the operating system to messages that the device type can understand. You need to have a newer version of your device driver because a newer version of a device driver has new features on it.

3. What are the steps required to install a peripheral device?

Adding a Peripheral Device to a System
Adding a new peripheral device that is not-pluggable usually involves the following:
1.Shutting down the system
2.Connecting the device to the system
3.Rebooting the system
Use How to Add a Peripheral Device to add the following devices that are not hot-pluggable to a system:
CD-ROM
Secondary disk drive
Tape drive
SBUS card
In some cases, you might have to add a third-party device driver to support the new device.
For information on hot-plugging devices, see Chapter 6, Dynamically Configuring Devices (Tasks).
How to Add a Peripheral Device

Become superuser.
(Optional) If you need to add a device driver to support the device, complete the procedure How to Add a Device Driver.
Create the /reconfigure file.
# touch /reconfigure
The /reconfigure file causes the Solaris software to check for the presence of any newly installed devices the next time you turn on or boot your system.
Shut down the system.
# shutdown -i0 -g30 -y

-i0
Brings the system to the 0 init state, which is the appropriate state for turning the system power off for adding and removing devices.
-g30
Shuts the system down in 30 seconds. The default is 60 seconds.
-y
Continues the system shutdown without user intervention. Otherwise, you are prompted to continue the shutdown process.
Select one of the following to turn off power to the system after it is shut down:
For SPARC platforms, it is safe to turn off power if the ok prompt is displayed.
For x86 platforms, it is safe to turn off power if the type any key to continue prompt is displayed.
Turn off power to all peripheral devices.
For the location of power switches on any peripheral devices, refer to the hardware installation guides that accompany your peripheral devices.
Install the peripheral device, making sure that the device you are adding has a different target number than the other devices on the system.
Often, a small switch is located at the back of the disk for selecting the target number.
Refer to the hardware installation guide that accompanies the peripheral device for information on installing and connecting the device.
Turn on the power to the system.
The system boots to multiuser mode, and the login prompt is displayed.
Verify that the peripheral device has been added by attempting to access the device.
For information on accessing the device, see Accessing Devices.

4. If a newly installed peripheral device does not function properly what steps can be taken to correct the problem?

Check if the product or the hardware you bought has no defect or company defects.

You should also check for driver updates for all your peripheral devices. If you're up to date, and you started having issues around the time you last updated a driver, try backing down to a lower version.

5. Explain the technique used to help protect data on a hard drive when doing a clean install?

One of the techniques available to help protect data is to divide the hard drive into multiple partitions. With a clean install, many technicians prefer to create one partition for data and a separate partition for the OS. This enables an OS to be upgraded without the risk of losing data. It also simplifies backup and recovery of data files.

6. Explain what a software patch is.

A patch is a piece of program code that can correct a problem or enhance thefunctionality of an application program or OS. They are usually provided by themanufacturer to repair a known vulnerability or reported problem.

As people begin to use a software program with frequency, they may note glitches or problems that were not observed during beta testing of the program. Alternately, older software can have compatibility issues with newer systems, or newer software may be incompatible with older systems. In these cases, and often to increase sales or use of software, programmers may create what is called a software patch, designed to fix small bugs, glitches, or address software-to-hardware or operating system compatibility issues.
If you notice consistent problems with a program, it’s easy to research on the Internet whether there is a software patch that might fix the program. In most cases these patches are free, and the majority of them are now simply downloaded from the Internet. A fair percentage of these patches help to address problems, but a poorly composed software patch may actually create new problems.
A software patch has several alternate names. When significant aspects of the software are altered, these may be called software updates instead. Some may be sold instead of available via free download. This is common with various computer games, where you can purchase what are called extension packs. These may change the rules of a game, add new features, or add new scenarios so people continue to play the game. When a game has been on the market for a while, it may be sold in a bundle with several extension packs.
Sometimes, programmers create small free features for current games that don’t warrant being called extension packs. For example in games like Zoo Tycoon® you can download tiny bits of programming that will add a few extra elements to a game, like extra animals you can raise or donation centers to collect more money from your guests. Also, when a game or other software type is popular but has existed for a few years, it may exhibit compatibility problems with newer software, newer computers or newer operating systems. Fans of a type of software that has not been updated to work with newer systems or computers often request that a software patch be made so they can extend the life of the programs they enjoy.
You’ll often find that you need a software patch for programs that were designed primarily for one type of hardware. For instance popular PC programs may not run or work as well on Mac®: computers. Sometimes a programmer needs to create both Mac and PC versions. Other times, a program designed for one system isn’t as effective on another and merely requires a software patch to fix glitches.
The modern installation of the software patch is much easier than in the past. This is especially true on PC systems where a person might have to go through multiple command sets in order to get the patch to work. Instead after downloading the software patch, you usually only need to install it, a matter of a couple of minutes depending upon the size of the patch and the speed of your computer.