hard disk bad sector problem, how to solve it?

saleemasraf (5:05:18 PM): do u know howw to repair a bad sector in a hard disk
sshaks (5:05:36 PM): u hv tools
sshaks (5:05:47 PM): give a search for disc utility tools in google
saleemasraf (5:06:01 PM): i know
saleemasraf (5:06:16 PM): but nasim panja told me to format and re partition
sshaks (5:06:32 PM): hmm ..
sshaks (5:06:42 PM): i dunno .. u will lose dta that way
saleemasraf (5:06:42 PM): those utilities according 2 him only hides d bad sectors
saleemasraf (5:06:47 PM): is that true
saleemasraf (5:07:08 PM): waise maine already format and partition kar diya hai
saleemasraf (5:07:15 PM): but bad sector increased
saleemasraf (5:07:20 PM): so kya kare
saleemasraf (5:07:35 PM): u r technical in this field
sshaks (5:07:41 PM): normally not .. how the whole thing works is this way
saleemasraf (5:07:49 PM): tell me now
saleemasraf (5:07:51 PM): ok
sshaks (5:07:52 PM): u have the physical hard disc
sshaks (5:08:06 PM): on it u have sectors to which the head writes
saleemasraf (5:08:10 PM): ok
sshaks (5:08:21 PM): on top of this u have a software driver which we call the file system
sshaks (5:08:34 PM): in ur PC it will be normally FAT32
saleemasraf (5:08:42 PM): yes
sshaks (5:08:55 PM): so this s/w knows what is written to what sector .. etc etc
sshaks (5:09:22 PM): now, when there is a bad sector, either the physical hard drive has a problem writing to the sector
saleemasraf (5:09:23 PM): go on pls
sshaks (5:09:49 PM): or the file system thinks there is something written there and doesn't overwrite it , or is prevented from over writing by other software etc etc
sshaks (5:10:02 PM): so if the physical hard disc has a problem, u can't repair it
saleemasraf (5:10:04 PM): hmmm
sshaks (5:10:17 PM): but if there is a s/w problem and the file system has some issues
sshaks (5:10:42 PM): then, reformatting (telling the file system that erase all ur pointers to the data and treat the disc as new) helps
saleemasraf (5:10:54 PM): ok
sshaks (5:11:23 PM): or else running a disc utility program which tries to write to tat sector inspite of errors and then reads back to see if its fine etc helps
sshaks (5:11:34 PM): so either way, it wud solve the problem
sshaks (5:11:52 PM): 1st try the disc utility since u won't lose data that way
saleemasraf (5:12:11 PM): inmy case after formating, and re partitioning the bad sector increased from two to twelve
sshaks (5:12:19 PM): otherwsie u will hv to backup all ur data to another Hard disc or burn CDs !
saleemasraf (5:12:19 PM): lol
saleemasraf (5:12:25 PM): now what u advice
sshaks (5:12:31 PM): if it doesn't help, format !
saleemasraf (5:12:35 PM): i have already losed my data
sshaks (5:12:44 PM): hehehe
sshaks (5:12:46 PM): ok!
saleemasraf (5:12:53 PM): BIG LOL
sshaks (5:13:00 PM): so formatting didn't help
saleemasraf (5:13:01 PM): nasim panja kahan ho tum
sshaks (5:13:05 PM): then run a disc utility
saleemasraf (5:13:07 PM): nope
saleemasraf (5:13:15 PM): u know any utility
sshaks (5:13:36 PM): http://www.freebyte.com/filediskutils/
sshaks (5:13:40 PM): hvn't used it though
saleemasraf (5:13:45 PM): ok
saleemasraf (5:13:49 PM): i will try
saleemasraf (5:14:12 PM): how r u?
saleemasraf (5:14:17 PM): busy in office
sshaks (5:14:26 PM): i am fine
sshaks (5:14:33 PM): kinda

DISTRIBUTED COMPUTING

Introduction

In computer science, a distributed system is an application that consists of components running on different computers concurrently. These components must be able to communicate and be designed to operate separately. As stated by Andrew S. Tanenbaum, "Distributed systems need radically different software than centralized systems do." The software he was discussing must be implemented in some form of distributed programming language.

Distributed computing is very attractive in part because interactive operation leaves most computers idle most of the time. The process which implements the distributed aspect — that is, one running on a machine normally devoted to other work — is usually specially designed to be a low priority process, using only computing power that would be wasted otherwise.

However, having a low-priority process constantly running prevents operating system power management routines from putting the processor into a low-power mode, resulting in increased electricity consumption. For some typically recent and high speed CPUs, the difference can be on the order of tens of watts for a single system.

Distributed computing is also an active area of computer science research with abundant literature. So promising is distributed computing technology that numerous US Department of Energy labs are linked for shared computational resources.

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Goal

There are many different types of distributed computing systems and many challenges to overcome in successfully architecting one. The main goal of a distributed computing system is to connect users and resources in a transparent, open, and scalable way. Ideally this arrangement is drastically more fault tolerant and more powerful than many combinations of stand-alone computer systems.

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Examples

An example of a distributed system is the World Wide Web. As you are reading a web page, you are actually using the distributed system that comprises the site. As you are browsing the web, your web browser running on your own computer communicates with different web servers that provide web pages. Possibly, your browser uses a proxy server to access the web contents stored on web servers faster and more securely. To find these servers, it also uses the distributed domain name system. Your web browser communicates with all of these servers over the Internet, via a system of routers which are themselves part of a large distributed routing system.

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Openness

Openness is the property of distributed systems that measures the extent to which it offers a standardized interface that allows it to be extended and scaled. It is clear that a system that easily allows more computing entities to be plugged into it and more features to be easily added to it has an advantage over a perfectly closed and self-contained system.

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Scalability

Main article Scalability

A scalable system is one that can easily be altered to accommodate changes in the amount of users, resources and computing entities affected to it. Scalability can measured in three different dimensions:

• Load scalability — A distributed system should make it easy for us to expand and contract its resource pool to accommodate heavier or lighter loads.
• Geographic scalability — A geographically scalable system is one that maintains its usefulness and usability, regardless of how far apart its users or resources are.
• Administrative scalability — No matter how many different organizations need to share a single distributed system, it should still be easy to use and manage.

Some loss of performance may occur in a system that allows itself to scale in one or more of these dimensions.

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Multiprocessor systems

A multiprocessor system is simply a computer that has more than one CPU on its motherboard or inside its own die. If the operating system is built to take advantage of this, it can run different processes on different CPUs, or different threads belonging to the same process.

Over the years, many different multiprocessing options have been explored for use in distributed computing. CPUs can be connected by bus or switch networks, use shared memory or their own private RAM, or even a hybrid approach.

These days, multiprocessor systems are available commercially for end-users, and mainstream operating systems like Mac OS X, Microsoft Windows and Linux already have built-in support for this. Additionally, recent Intel CPUs have begun to employ a technology called Hyperthreading that allows more than one thread to run on the same CPU. Mac OS X has had this for some time.

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Multicomputer systems

A multicomputer system is a system made up of several independent computers interconnected by a telecommunications network.

Multicomputer systems can be homogeneous or heterogeneous: A homogeneous distributed system is one where all CPUs are similar and are connected by a single type of network. They are often used for parallel computing which is a kind of distributed computing where every computer is working on different parts of a single problem.

In contrast a heterogeneous distributed system is one that can be made up of all sorts of different computers, eventually with vastly differing memory sizes, processing power and even basic underlying architecture. They are in widespread use today, with many companies adopting this architecture due to the speed with which hardware goes obsolete and the cost of upgrading a whole system simultaneously.

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Architecture

Various hardware and software architectures exist that are usually used for distributed computing. At a lower level, it is necessary to interconnect multiple CPUs with some sort of network, regardless of that network being printed onto a circuit board or made up of several loosely-coupled devices and cables. At a higher level, it is necessary to interconnect processes running on those CPUs with some sort of communication system.

• Client-server — Smart client code contacts the server for data, then formats and displays it to the user. Input at the client is committed back to the server when it represents a permanent change.
• 3-tier architecture — Three tier systems move the client intelligence to a middle tier so that stateless clients can be used. This simplifies application deployment. Most web applications are 3-Tier.
• N-tier architecture — N-Tier refers typically to web applications which further forward their requests to other enterprise services. This type of application is the one most responsible for the success of application servers.
• Tightly coupled (clustered) — refers typically to a set of highly integrated machines that run the same process in parallel, subdividing the task in parts that are made individually by each one, and then put back together to make the final result.
• Peer-to-peer — an architecture where there is no special machine or machines that provide a service or manage the network resources. Instead all responsibilities are uniformly divided among all machines, known as peers.

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Parallelism

Main article Parallel computing

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Computing Taxonomies

The types of distributed computers are based on Flynn's taxonomy of systems; single instruction, single data (SISD), multiple instruction, single data (MISD), single instruction, multiple data (SIMD) and multiple instruction, multiple data (MIMD). Other taxonomies and architectures availible at Computer architecture and in Category:Computer architecture.

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Computer clusters

Main article Cluster computing

A cluster is multiple stand-alone machines acting in parallel across a local high speed network. Distributed computing differs from cluster computing in that computers in a distributed computing environment are typically not exclusively running "group" tasks, whereas clustered computers are usually much more tightly coupled. The difference makes distributed computing attractive because, when properly configured, it can use computational resources that would otherwise be unused. It can also make available computing resources which would otherwise be impossible.

The Second Life grid is a heterogeneous multicomputer and so are most Beowulf clusters.

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Grid computing

Main article Grid computing

A grid consists of multiple computers sharing information over the Internet. Most use idle time on many thousands of computers throughout the world. Such arrangements permit handling of data that would otherwise require the power of expensive supercomputers or would have been impossible to analyze otherwise.

Distributed computing projects also often involve competition with other distributed systems. This competition may be for prestige, or it may be a means of enticing users to donate processing power to a specific project. For example, stat races are a measure of what the most distributed work a project has been able to compute over the past day or week. This has been found to be so important in practice that virtually all distributed computing projects offer online statistical analyses of their performances, updated at least daily if not in real-time.

See List of distributed computing projects for more information on specific projects.

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See also

• Sequential consistency
• Memory models
  • Shared memory
  • Distributed memory
  • Distributed shared memory
• Render farms — The rendering of 3D computer images and movies is often spread between several computers to speed up the process.

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Distributed computing infrastructure

• Remote procedure call — This distribution system maps function calls to the network.
• Distributed objects — Systems like CORBA, Microsoft D/COM, Java RMI, ReplicaNet [1] (http://www.replicanet.com/), and others that try to map object oriented design onto the network.
• SOAP
• XML-RPC
• GLOBE [2] (http://www.cs.vu.nl/~steen/globe/) — Maintained by Andrew S. Tanenbaum and others.
• Acute [3] (http://www.cl.cam.ac.uk/users/pes20/acute/) — Distributed functional programming with migration based on OCaml.
• PYRO (http://pyro.sourceforge.net/) — Python Remote Objects - Free Software Distributed Object Technology
• BOINC — Berkeley Open Infrastructure for Network Computing

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Distributed computing conferences and journals

• The International Conference on Dependable Systems and Networks (http://www.dsn.org/)
• Symposium on Principles of Distributed Computing (http://www.podc.orgACM)
• Journal of Parallel and Distributed Computing (http://www.academicpress.com/jpdc)
• IEEE transactions on Parallel and Distributed Systems (http://www.computer.org/tpds/about.htm)
• Distributed Computing (http://www.springeronline.com)

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Proprietary infrastructure

• United Devices [4] (http://www.ud.com) — Has the largest commercial distributed computing network.
• DataSynaspe [5] (http://www.datasynapse.com)
• Digipede [6] (http://www.digipede.net) — Has a commercial, all .NET distributed computing solution for Windows.
• Entropia [7] (http://www.entropia.com) — Vendor of distributed computing software technologies.
• ICE
• OfficeGRID [8] (http://www.officegrid.net) — A grid solution from MESH-Technologies A/S (http://www.meshtechnologies.com).
• Xgrid — Software developed by Apple's Advanced Computation Group.

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See also

• Application server
• Distributed computing category
• Distributed Systems wikibook
• Distributed computing environment
• Distributed memory
• Distributed operating system
• History of computing category
  • History of computing
• Supercomputer
• List of distributed computing publications
• List of distributed computing projects
• Logical clocks
• Network of Workstations
• Parallel computing
• Peer to peer
• Render farm
• Snapshot algorithm
• Software componentry

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External links

• A primer on distributed computing (http://www.bacchae.co.uk/docs/dist.html)
• distributedcomputing.info
• Distributed Systems Department (http://dsd.lbl.gov/)
• Distributed.net: Node Zero (http://www.distributed.net/)
• Info Sharkz Distributed Computing (http://www.infosharkz.com/dc/)

Retrieved from "http://en.wikipedia.org/wiki/Distributed_computing"

how to repair bad sector i n a hard disk

zaman_sn (6:50:37 PM): yes
saleemasraf (6:50:45 PM): hi
saleemasraf (6:50:49 PM): ki korisa
zaman_sn (6:50:51 PM): hi
saleemasraf (6:50:59 PM): bohiye thaka neki
zaman_sn (6:51:01 PM): eku nai kora
zaman_sn (6:51:16 PM): no slept
saleemasraf (6:51:20 PM): ok
saleemasraf (6:51:35 PM): can u tellme how to repair bad sector in hard disk
zaman_sn (6:51:47 PM): format it
saleemasraf (6:52:21 PM): than
zaman_sn (6:52:35 PM): there is a software also which hides the bad sector, but it is no good
zaman_sn (6:52:57 PM): formatting it will make new track
zaman_sn (6:53:40 PM): formtting is a good solution, but take back up of files
saleemasraf (6:53:49 PM): only formatting
zaman_sn (6:53:55 PM): yes
saleemasraf (6:53:55 PM): nothing else
saleemasraf (6:54:09 PM): no use of any software
saleemasraf (6:54:18 PM): http://www.unistal.com/disk_repair.html
zaman_sn (6:54:26 PM): no nothing else. but what is d extent of damage?
saleemasraf (6:54:31 PM): pls view this url
saleemasraf (6:54:44 PM): only one point in drive d
saleemasraf (6:54:57 PM): i have two drives in d office computer
saleemasraf (6:55:01 PM): c &D
zaman_sn (6:55:25 PM): then just format
saleemasraf (6:56:06 PM): ok
saleemasraf (6:56:13 PM): have u seen d url
zaman_sn (6:56:23 PM): please wait
zaman_sn (6:58:23 PM): yes i have seen the site. that's what i was talkinmg about. this software hides the bad sector. just format ur hdd
zaman_sn (6:59:17 PM): but just download the software and see what is it.
saleemasraf (6:59:43 PM): ok
saleemasraf (7:00:12 PM): so just format
saleemasraf (7:00:14 PM): ok
zaman_sn (7:00:19 PM): yes
saleemasraf (7:00:23 PM): saah khala
zaman_sn (7:00:41 PM): nai khua. magribar pisat
saleemasraf (7:01:18 PM): magrib tu ki bastu
zaman_sn (7:02:14 PM): ye take nejane pai, urdut pachimak magrib buli koi
zaman_sn (7:03:33 PM): pachimat beli dubile aami namaz porhu
saleemasraf (7:03:44 PM): ye
saleemasraf (7:03:50 PM): hoi niki
zaman_sn (7:04:00 PM): hoi tu
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saleemasraf (7:05:32 PM): bahut bhabi sinti likhisa dei
zaman_sn (7:05:39 PM): azn honi abasye namaz porhib pari
saleemasraf (7:06:06 PM): amar junab tuwe dawat thakile hunkalay azan diye
zaman_sn (7:06:21 PM): i am because i think
saleemasraf (7:06:21 PM): so cant trust him
zaman_sn (7:07:05 PM): bapre. ki modern junab
saleemasraf (7:07:22 PM): he also uses mobile and
saleemasraf (7:07:27 PM): oppps computerr
zaman_sn (7:07:46 PM): he belongs to post-modernism
saleemasraf (7:07:48 PM): and rides a viki
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saleemasraf (7:08:46 PM): assa,,,,  tupi pindhilay helmet pin dhibo lagay nay nalagay
zaman_sn (7:09:38 PM): our faith is not in our darhi, but in our inner self. only allah knows about the depth of our faith.
zaman_sn (7:10:13 PM): helmet pindha bhal. accident hole murtu sepeta huar bhoi nethake
zaman_sn (7:11:57 PM): hey
zaman_sn (7:12:09 PM): hey hey hey
zaman_sn (7:12:29 PM): ki hol? asa ne?
saleemasraf (7:13:56 PM): moi nai dey
saleemasraf (7:14:04 PM): saah khaboi loi jao
zaman_sn (7:14:44 PM): sahor logt ki khaba? sah dekhun comutrar usartukhaba para
saleemasraf (7:14:59 PM): tab
saleemasraf (7:15:20 PM): moi tabassum
zaman_sn (7:15:36 PM): ok hi tabbassum
saleemasraf (7:15:46 PM): kene asa
saleemasraf (7:16:06 PM): amar ghorot ahiba n4eki
zaman_sn (7:16:26 PM): bhal tumar ki khobor?
saleemasraf (7:16:29 PM): kuwa etiya
zaman_sn (7:16:37 PM): aahim
saleemasraf (7:16:40 PM): saah khini computer usorot loi anilu
saleemasraf (7:16:53 PM): aru aji ki korila din tu
zaman_sn (7:16:59 PM): nepelab kintu
zaman_sn (7:17:11 PM): nepalaba kintu
saleemasraf (7:17:11 PM): azan dilay
saleemasraf (7:17:19 PM): magribor kijani
zaman_sn (7:17:45 PM): magribar azan. hura guri sapriloi monot porise
saleemasraf (7:17:59 PM): moi hura guri dekha nai
zaman_sn (7:18:00 PM): eeyatu azan dile
saleemasraf (7:18:09 PM): handohor guri dekhisu
saleemasraf (7:18:19 PM): sauolor guri dekhisu
zaman_sn (7:18:50 PM): moioo nai dekha. pise hura guri sapori aaru magribar azan kiba meele