Showing posts with label Computer. Show all posts
Showing posts with label Computer. Show all posts

Thursday, April 19, 2007

PCI Express





PCI Express, officially abbreviated as PCIe (and sometimes confused with PCI Extended, which is officially abbreviated as PCI-X), is a computer system bus/expansion card interface format. It was designed as a much faster interface to replace PCI, PCI-X, and AGP interfaces for computer expansion cards and graphics cards. The PCI Express (PCIe) physical connection (slot) is completely different to those of the older standard PCI slots or those for PCI Extended (PCI-X).

As with all computing standards, PCIe is a technology which receives further development and improvement. The current standard version in general use at time of writing is PCIe 1.1; however, PCI-SIG announced the availability of the PCI Express Base 2.0 specification on 15 January 2007. PCIe 2.0 doubles the PCIe bus standard throughput or bandwidth from 2.5Gbps to 5Gbps. PCIe 2.0 is still compatible with PCIe 1.1 as a physical interface slot and from within software, so older cards will still be able to work in machines fitted with this new version. Further information on PCIe 2.0 is detailed below.

PCIe is a flexible hybrid serial-parallel interface format. That is, it uses multiple connections each of which individually transmit a single stream of data in parallel to one another. This type of interfacing is sometimes referred to as Channel bonding. PCIe 1.1 transfers data at 250 MB/s in each direction per lane. With a maximum of 32 lanes, PCIe allows for a total combined transfer rate of 8 GB/s in each direction. To put these figures into perspective, a single lane has nearly twice the data rate of normal PCI, a four lane slot has a comparable data rate to the fastest version of PCI-X 1.0, and an eight lane slot has a data rate comparable to the fastest version of AGP.

Unlike preceding PC expansion interface standards, PCIe is both full duplex and point to point. This means that while standard PCI-X (133mhz 64 bit) and PCIe x4 have the same data transfer rate, PCIe x4 will give better performance if multiple device pairs are communicating simultaneously or if communication within a single device pair is bidirectional.

DDR2 vs DDR

Secara fisik, tidak ada perbedaan yang mencolok antara DDR2 dan DDR. Bahkan letak lekukan penanda (notch) juga sekilas terasa mirip.

184 pin vs 240 pin
Secara fisik yang gampang terlihat adalah jumlah pin-nya. DDR yang selama ni Anda kenal memiliki 184 pin. Sedangkan DDR2 berjumlahkan 240 pin. Lekukan penanda, agar DRAM tidak salah terpasang juga bergeser sedikit. Tidak lebih dari 3 mm. Jadi, hati-hatilah dalam memasangnya, apalagi jika di motherboard tersebut tersedia dua macam slot, baik DDR maupun DDR2. Hal ini masih banyak dijumpai pada beberapa motherboard dengan chipset 915P ataupun 915G yang memang masih mendukung DDR 400/333.

2,5 V vs 1,8 V
Seperti peralihan modul DRAM sebelumnya, terjadi juga perubahan voltage yang digunakan. DDR membutuhkan tegangan sebesar 2,5 Volt. Sedangkan DDR2 membutuhkan tegangan sebesar 1,8 Volt. Secara teori, DDR2 tidak akan menghasilkan panas yang lebih tinggi dibanding DDR. Akhirnya ada juga komponen baru untuk chipset ini yang tidak menyumbang tambahan panas.

DDR2/533 vs DDR400
Untuk sementara, dua kecepatan inilah yang disepakati oleh JEDEC. DDR2/533 jika dioperasikan dengan dual-channel akan dapat menghasilkan bandwidth memory sebesar 8,5 GB/s. Bandingkan dengan dual channel DDR400 yang “hanya” menghasilkan bandwidth maksimal sebesar 6,4 GB/s. Selanjutnya akan hadir DDR2/677 dan DDR2/800 yang semakin membuka ketersediaan memory bandwith.

Pengujian
Yang akan dibandingkan di sini adalah kemampuan DDR dibandingkan penantangnya DDR2. kami memberikan perbandingan antara DDR2 pada chipset 925X, dibandingkan dengan DDR pada chipset 875P. Sebagai pembanding, kami tampilkan juga kinerja DDR dan DDR2 yang terpasang pada motherboard dengan chipset 915P. Karena pada motherboard ini tersedia baik slot DIMM untuk DDR maupun untuk DRAM DDR2.

Kesimpulan
Lagi-lagi ini di luar dugaan kami sebelumnya. Chipset Intel 925X bergabung dengan DDR2 belum jauh lebih baik dibandingkan dengan chipset 875P dengan DDR2. Sedangkan kinerja DDR2 dibanding DDR pada chipset Intel 915P juga tidaklah terlalu menggembirakan.

Akankah ini hanya sebuah blunder, seperti saat Intel memperkenalkan RDRAM dengan chipset Intel 840 (RDRAM PC800 dual channels). Semoga tidak, karena kita sudah mengetahui nasib keduanya (RDRAM dan Intel 840) yang minim peminat di pasaran, karena harganya yang kelewat tinggi jika dibandingkan dengan peningkatan kinerja yang dimiliki.

Thursday, March 22, 2007

enable task manager on my system when it has been disabled by administrator

=============== start copy here ==================
REGEDIT4

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableRegistryTools"=dword:00000000

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableTaskMgr"=dword:00000000
=============== end copy here ==================

copy to notepad, and save with name repair.reg

Friday, December 01, 2006

Wibree



Wibree is the first wireless technology to solve the following needs in a single solution.

* Ultra low peak and average power consumption in both active and idle modes
* Ultra low cost & small size for accessories & human interface devices (HID)
* Minimal cost & size addition to mobile phones & PCs
* Global, intuitive & secure multi-vendor interoperability

Wibree device architecture

Wibree specification has been created by having two equally important implementation alternatives in mind, namely dual-mode and stand-alone. In the dual mode implementation the Wibree functionality is an add-on feature inside Bluetooth circuitry sharing a great deal of existing functionality resulting in a minimal cost increase compared to existing products. The dual modes are targeted at mobile phones, multimedia computers and PCs. The stand alone implementations are power and cost optimized designs targeted at, for example, sport, wellness, and human HID product categories.

Wibree radio specification

Wibree radio specification enables dual-mode implementations to reuse Bluetooth RF part but also to guarantee ultra low power consumption for devices with embedded stand-alone implementation of the Wibree specification. Wibree operates in 2.4 GHz ISM band with physical layer bit rate of 1 Mbps and provides link distance of 5-10 meters.
Wibree link layer specification

Wibree link layer provides ultra low power idle mode operation, simple device discovery and reliable point-to-multipoint data transfer with advanced power-save and encryption functionalities. The link layer provides means to schedule Wibree traffic in between Bluetooth transmissions.

Wibree host & profile specifications

In the first phase Wibree provides sensor, HID and watch user interface profiles.

Friday, September 15, 2006

ROBOT

A robot is an electro-mechanical device that can perform autonomous or preprogrammed tasks. A robot may act under the direct control of a human (eg. the robotic arm of the space shuttle) or autonomously under the control of a programmed computer. Robots may be used to perform tasks that are too dangerous or difficult for humans to implement directly (e.g. nuclear waste clean up) or may be used to automate repetitive tasks that can be performed with more precision by a robot than by the employment of a human (e.g. automobile production.)

Robot can also be used to describe an intelligent mechanical device in the form of a human. This form of robot (commonly referred to as an android) is common in science fiction stories.However, such robots have yet to become commonplace in reality, especially with the difficulties (and expenses) involved in making a bipedal machine balance itself or move in human-like ways without losing balance (see Current Developments below).Internet bots are named after the word robot because they perform mundane, repetitive tasks.


The
word robot is used to refer to a wide range of machines, the common feature of
which is that they are all capable of movement and can be used to perform
physical tasks. Robots take on many different forms, ranging from humanoid,
which mimic the human form and way of moving, to industrial, whose appearance is dictated by the function they are to perform. Robots can be grouped generally as mobile robots (eg. autonomous vehicles), manipulator robots (eg. industrial robots) and Self reconfigurable robots, which can conform themselves to the task at hand. Robots may be controlled directly by a human, such as remotely-controlled bomb-disposal robots, robotic arms, or shuttles, or may act according to their own decision making ability, provided by artificial intelligence. However, the majority of robots fall in-between these extremes, being controlled by pre-programmed computers. Such robots may include feedback loops such that they can interact with their environment, but do not display actual intelligence.

The word "robot" is also used in a general sense to mean any machine which mimics the actions of a human (biomimicry), in the physical sense or in the mental sense. It comes from the Czech and Slovak word robota, labour or work (also used in a sense of a serf). The word robot first appeared in Karel Čapek's science fiction playR.U.R. (Rossum's Universal Robots) in 1921, and was probably invented by the author's brother, painter Josef Čapek. See the article about Karel
Čapek for more detailed

Robots are growing in complexity and their use in industry is becoming more widespread. The main use of robots has so far been in the automation of mass production industries, where the same, definable tasks must be performed repeatedly in exactly the same fashion. Car production is the primary example of the employment of large and complex robots for producing products. Robots are used in that process for the painting, welding and assembly of the cars. Robots are good for such tasks because the tasks can be accurately defined and must be performed the same every time, with little need for feedback to control the exact process being performed. Industrial Robots can be manufactured in a wide range of sizes and so can handle much larger tasks than a human could.

They are also useful in environments which are unpleasant or dangerous for humans to work in, for example bomb disposal, work in space or underwater, in mining, and for the cleaning of toxic waste. Robots are also used for patrolling these toxic areas, robots equipped for this job are e.g. the Robowatch OFRO, and Robowatch MOSRO.

Often this is referred to as the "Three D's: Dull, Dirty and Dangerous" work. Hundreds of bomb disposal robots such as the iRobot Packbot and theFoster-Miller Talon are being used in Iraqand Afghanistan by the U.S. military to defuse roadside bombs, or improvised explosive devices (IED's) in an activity known as Explosive Ordinance Disposal (EOD). Automated Guided Vehicles (AGVs) are moveable robots that are used in large facilities such as warehouses hospitals and container ports, for the movement of goods, or even for safety and security patrols. Such vehicles follow wires, markers or laser-guidance to navigate around the location and can be programmed to move between places to deliver goods or patrol a certain area. Top manufacturers include

Transbotics, FMC and Jervis B Webb makes AGV "brains" used in freely moving autonomous vehicles that do not require fixed paths as earlier AGVs have done.



Domestic robots are now available that perform simple tasks such as vacuum cleaning and grass cutting. By the end of 2004 over 1,000,000 vacuum cleaner units had been sold. Examples of these domestic robots are the Scooba and Roomba robots from iRobot Corporation, Friendly Robotics' Robomower, Electrolux's Automower, and Samsung.

Other domestic robots have the aim of providing companionship (social robots) or play partners (ludobots) to people. Examples are Sony's Aibo, a commercially successful robot pet dog, Paro, a robot baby seal intended to soothe nursing home patients, and Wakamaru, a humanoid robot ntended for elderly and disabled people. Other humanoid robots are in development with the aim of being able to provide robotic functions in a form that may be more aesthetically pleasing to customers, thereby increasing the likelihood of them being accepted in society. PLEN has been put up for sale.
Robots perform in arts festivals and at museums with works such as James Seawright's House Plants, 1983, in which an artificial flower opens in response to viewer interaction or Ken Rinaldo's Autotelematic Spider Bots, 2006 where robots that appear like spiders, see like bats and act like ants interact with the public and structure each others behaviors through bluetooth communication. One of the earliest electronic art robots is Jim Pallas' 1976 Blue Wazoo which, using TTL IC devices, responds to sound and light with a repertoire of LED patterns, movements, inflations, deflations, whirs, clicks and jiggles.
For education in schools and high schools and mechatronics training in companies robot kits are becoming more and more popular. On the schools side there exists kits from LEGO, Parallax, Inc or Fischertechnik made of plastics components, Microbric, which uses its mainboard as a chassis & on the more professional side there exists e.g. the qfix robot kit and VexLABS robotics kit made of aluminium parts.

Warfare

The future of modern warfare will be fought by automated weapons systems. The U.S. Military is investing heavily in research and development towards testing and deploying increasingly automated systems. The most prominent system currently in use is the unmanned aerial vehicle (IAI Pioneer & RQ-1 Predator) which can be armed with Air-to-Ground missiles and remotely operated from a command center in reconnaissance roles. DARPA has hosted competitions in 2004 & 2005 to involve private companies and universities to develop unmanned ground vehicles to navigate through rough terrain in the Mojave Desert for a final prize of $2 Million. The field of artillery has also seen some promising research with an experimental weapons system named "Dragon Fire II" which automates the loading and ballistics calculations required for accurate predicted fire, providing a 12 second response time to artillery support requests. However, weapons of warfare have one limitation in becoming fully autonomous: there remain intervention points which requires human input to ensure that targets are not within restricted fire areas as defined by Geneva Conventions for the laws of war.

There have been some developments towards developing autonomous fighter jets and bombers. The use of autonomous fighters and bombers to destroy enemy targets is especially promising because of the lack of training required for robotic pilots, autonomous planes are capable of performing maneuvers which couldn't otherwise be done with human pilots (due to high amount of G-Force), plane designs don't require a life support system, and a loss of a plane doesn't mean a loss of a pilot. However, the largest draw back to robotics is their inability to accommodate for non-standard conditions. The idea of artificial people dates at least as far back as the ancient legend of Cadmus, who sowed dragon teeth that turned into soldiers, and the myth of Pygmalion, whose statue of Galatea came to life. In classical mythology, the deformed god of metalwork (Vulcan or Hephaestus) created mechanical servants, ranging from intelligent, golden handmaidens to more utilitarian three-legged tables that could move about under their own power.
Jewish legend tells of the Golem, a clay statue animated by Kabbalistic magic. Similarly, in the Younger Edda, Norse mythology tells of a clay giant, Mökkurkálfi or Mistcalf, constructed to aid the troll Hrungnir in a duel with Thor, the God of Thunder.

The word robot was introduced by Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots) which was written in 1920 (See also Robots in literature for details of the play). However, the verb robotovat, meaning "to work" or "to slave", and the noun robota (meaning corvée) used in the Czech and Slovak languages, has been used since the early 10th
century. It was suggested that the word robot had been coined by Karel Čapek's brother, painter and writer Josef Čapek.

Concepts akin to today's robot can be found as long ago as 450 BC when the Greek mathematician Archytas of Tarentum postulated a mechanical bird he called "The Pigeon" which was propelled by steam. Heron of Alexandria (10AD-70AD) made numerous innovations in the field of automata, including (allegedly) one that could speak.

Al-Jazari (1136-1206) an Ortoqid (Artuk) Turkish inventor designed and constructed automatic machines such as water clocks, kitchen appliances and musical automats powered by water (See one of his works at). One of the first recorded designs of a humanoid robot was wade by Leonardo da Vinci in around 1495. Da Vinci's notebooks, rediscovered in the 1950s, contain detailed drawings of a mechanical knight able to sit up, wave its arms and move its head and jaw. The design is likely to be based on his anatomical research recorded in the Vitruvian Man. It is not known whether he attempted to build the robot

An early automaton was created 1738 byJacques de Vaucanson, who created a mechanical duck that was able to eat grain, flap its wings, and excrete. Many consider the first robot in the modern sense to be a teleoperated boat, similar to a modernROV, devised by Nikola Tesla and demonstrated at an 1898 exhibition in Madison Square Garden. Based on his patents 613,809, 723,188 and 725,605 for "teleautomation", Tesla hoped to develop the "wireless torpedo" into an automated weapon system for the US Navy. (Cheney 1989) Tesla also proposed but did not build remotely operated war planes and ground vehicles. He also predicted these remote controlled machines were merely precursors of "machines possessed of their own intelligence" (Cheney 1989). See also the PBS website article (with photos) :

Tesla - Master of Lightning: Race of Robots
In the thirties, Westinghouse made a humanoid robot known as
Elektro. It was exhibited at the 1939 and 1940 World's Fairs while the first electronic
autonomous robots were created by Grey Walter at Bristol University, England in 1948.

The first human to be killed by a robot was 37 year-old Kenji Urada, a Japanese factory worker, in 1981. According the Economist.com, Urada "climbed over a safety fence at a Kawasaki plant to carry out some maintenance work on a robot. In his haste, he failed to switch the robot off properly. Unable to sense him, the robot's powerful hydraulic arm kept on working and accidentally pushed the engineer into a grinding machine."

Current developments

The development of a robot with a natural human or animal gait is incredibly difficult and requires a large amount of computational power. Now that background technologies of behavior, navigation and path planning have been solved using basic wheeled robots, roboticists are moving on to develop walking robots (eg. SIGMO, QRIO, ASIMO & Hubo). One approach to walk control is Passive dynamics, where the robot's geometry is such that it will almost walk without active control.
Initial work has focused on multi-legged robots (eg. Aibo), such as hexapods, as they are statically stable and so are easier to work with, whereas a bipedal robot must be able to balance. The balancing problem is taken to an extreme by the Robotic unicycle. A problem with the development of robots with natural gaits is that human and animal bodies utilize a very large number of muscles in movement and replicating all of those mechanically is very difficult and expensive. This field of robot research has become known as Biomorphic robotics.

Progress is being made in the field of feedback and tactile sensors which allow a robot to sense their actions and adjust their behavior accordingly. This is vital to enable robots to perform complex physical tasks that require some
active control in response to the situation.

Medical robotics is a growing field and regulatory approval has been granted for the use of robots in minimally invasive procedures. Robots are being used in performing highly delicate, accurate surgery, or to allow a surgeon who is located remotely from their patient to perform a procedure using a robot controlled remotely. More recently, robots can be used autonomously in surgery. Experimental winged robots and other examples exploiting biomimicry are also in early development. So-called "nanomotors" and "smart wires" are expected to drastically simplify motive power, while in-flight stabilization seems likely to be improved by extremely small gyroscopes. A significant driver of this work is military research into spy technologies. Energetically autonomous robots, is a field of study under the category of biologically inspired robotics, which aims to develop artificial agents that can remain self-sustainable in natural environments with minimum human intervention. This field of research spreads further into the fields of alternative energy sources and waste management, as it integrates the

Microbial Fuel Cell technology with robotics, and allows for waste or food waste to be the 'fuel'. This class of robots is at the very early stages of development, however with great impact in applications such as the aforementioned unpleasant or dangerous for humans environments. Two examples of energetically autonomous robots that exist today are EcoBots I and II.

Tactile sensors and artificial skin are close to providing robots with a human-like sense of touch. Technology-friendly South Korea says it will have a robot in every home by 2015-2020.Robot News gives breaking news in robotic developments.

Dangers and fears
Although robots have not developed to the stage where they pose any threat or danger to society, fears and concerns about robots have been repeatedly expressed in a wide range of books and films. The principal theme is the robots' intelligence and ability to act could exceed that of humans, that they could develop a conscience and a motivation to take over or destroy the human race. (See The Terminator) Frankenstein (1818),sometimes called the first science fiction novel, has become synonymous with the theme of a robot or monster advancing beyond its creator. Probably the best known author to work in this area is Isaac Asimov who has placed robots and their interaction with society at the center of many of his works. Of particular interest are Asimov's Three Laws of Robotics. Asimov also coined the term "Robotics" as the science or study of the technology associated with robots.
Currently, malicious programming or unsafe use of robots may be the biggest danger. Although industrial robots may be smaller and less powerful than other industrial machines, they are just as capable of inflicting severe injury on humans. However, since a robot can be programmed to move in different trajectories depending on its task, its movement can be unpredictable for a person standing in its reach. Therefore, most industrial robots operate inside a security fence which separates them from human workers. Manuel De Landa has theorized that humans are at a critical and significant juncture where humans have allowed robots, "smart missiles," and autonomous bombs equipped with artificial perception to make decisions about killing us. He believes this represents an important and dangerous trend where humans are transferring more of our cognitive structures into our machines.

Even without malicious programming, a robot, especially a future model moving freely in a human environment, is potentially dangerous because of its large moving masses, powerful actuators and unpredictably complex behavior. A robot falling on someone or just stepping on his foot by mistake could cause much more damage to the victim than a human being of the same size. Designing and programming robots to be intrinsically safe and to exhibit safe behavior in a human environment is one of the great challenges in robotics. Developing a robot with a conscience may be helpful.

Literature

List of fictional robots and androids

Robots have frequently appeared as characters in works of literature and the first use of the word "robot" in literature can be found in Karel Capek's play R.U.R. (Rossum's Universal Robots), written in 1920. Isaac Asimov has written many volumes of science fiction focusing on robots in numerous forms and guises. Asimov contributed greatly to reducing the Frankenstein complex, which dominated early works of fiction involving robots. His three laws of robotics have become particularly well known for codifying a simple set of behaviors for robots to remain at the service of their human creators.
Numerous words for different types of robots are now used in literature. Robot has come to mean mechanical humans, while android is used for organic artificial humans and cyborg or "bionic man" for a human form that is a mixture of organic and mechanical parts. Organic artificial humans have also been referred to as "constructs" (or "biologicalconstructs").


Robotics
robotics is the science and technology of robots, their design, manufacture, and application. Robotics requires a working knowledge of electronics, mechanics, and software and a person working in the field has become known as a roboticist. The word robotics was first used in print by Isaac Asimov, in his science fiction short story "Runaround" (1941).
Although the appearance and capabilities of robots vary vastly, all robots share the features of a mechanical, movable structure under some form of control. The structure of a robot is usually mostly mechanical and can be called kinematic chain (its functionality being akin to the skeleton of a body). The chain is formed of links (its bones), actuators (its muscles) and joints which can allow one or more degrees of freedom. Most contemporary robots use open serial chains in which each link connects the one before to the one after it. These robots are called serial robots and often resemble the human arm. Some robots, such as the

Stewart platform, use closed parallel kinematic chains. Other structures, such as those that mimic the mechanical structure of humans, various animals and insects, are comparatively rare. However, the development and use of such structures in robots is an active area of research (e.g. biomechanics). Robots used as manipulators have an end effector mounted on the last link. This end effector can be anything from a welding device to a mechanical hand used to manipulate the environment.

The mechanical structure of a robot must be controlled to perform tasks. The control of a robot involves three distinct phases - perception, processing and action (robotic paradigms). Sensors give information about the environment or the robot itself (e.g. the position of its joints or its end effector). Using strategies from the field of control theory, this information is processed to calculate the appropriate signals to the actuators (motors) which move the mechanical structure. The control of a robot involves various aspects such as path planning, pattern recognition, obstacle avoidance, etc. More complex and adaptable control strategies can be referred to as artificial intelligence.

Any task involves the motion of the robot. The study of motion can be divided into kinematics anddynamics. Direct kinematics refers to the calculation of end effector position, orientation, velocity and acceleration when the corresponding joint values are known. Inverse kinematics refers to the opposite case in which required joint values are calculated for given end effector values, as done in path planning. Some special aspects of kinematics include handling of redundancy (different possibilities of performing the same movement), collision avoidance andsingularity avoidance. Once all relevant positions, velocities and accelerations have been calculated using kinematics, methods from the field of dynamics are used to study the effect of forces upon these movements. Direct dynamics refers to the calculation of accelerations in the robot once the applied forces are known. Direct dynamics is used in computer simulations of the robot. Inverse dynamics refers to the calculation of the actuator forces necessary to create a prescribed end effector acceleration. This information can be used to improve the control algorithms of a robot.
In each area mentioned above, researchers strive to develop new concepts and strategies, improve existing ones and improve the interaction between these areas. To do this, criteria for "optimal" performance and ways to optimize design, structure and control of robots must be developed and implemented.






Sunday, August 27, 2006

Computer



A computer is a machine for manipulating data according to a list of instructions known as a program.

Computers are extremely versatile. In fact, they are universal information-processing machines. According to the Church–Turing thesis, a computer with a certain minimum threshold capability is in principle capable of performing the tasks of any other computer. Therefore, computers with capabilities ranging from those of a personal digital assistant to a supercomputer may all perform the same tasks, as long as time and memory capacity are not considerations. Therefore, the same computer designs may be adapted for tasks ranging from processing company payrolls to controlling unmanned spaceflights. Due to technological advancement, modern electronic computers are exponentially more capable than those of preceding generations (a phenomenon partially described by Moore's Law).

Computers take numerous physical forms. Early electronic computers were the size of a large room, while entire modern embedded computers may be smaller than a deck of playing cards. Even today, enormous computing facilities still exist for specialized scientific computation and for the transaction processing requirements of large organizations. Smaller computers designed for individual use are called personal computers. Along with their portable equivalent, the laptop computer and personal computers are ubiquitous information processing and communication tools that are usually what most people think of as "a computer". However, the most common form of computer in use today is the embedded computer. Embedded computers are usually relatively simple and physically small computers used to control another device. They may control machines from fighter aircraft to industrial robots to digital cameras.

History of computing


Originally, the term "computer" referred to a person who performed numerical c alc ulations, often with the aid of a mechanical calculating device or analog computer. Examples of these early devices, the ancestors of the computer, included the abacus and the Antikythera mechanism, an ancient Greek device for calculating the movements of planets which dates from about 87 BC.[1] The end of the Middle Ages saw a reinvigoration of European mathematics an d engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers.[2]

In 1801, Joseph Marie Jacquard made an improvement to existing loom designs that used a series of punched paper cards as a program to weave intricate patterns. The resulting Jacquard loom is not considered a true computer but it was an important step in the development of modern digital computers.

Charles Babbage was the first to conceptualize and design a fully programmable computer as early as 1820, but due to a combination of the limits of the technology of the time, limited finance, and an inability to resist tinkering with his design, the device was never actually constructed in his lifetime. By the end of the 19th century a number of technologies that would later prove useful in computing had appeared, such as the punch card and the vacuum tube, and large-scale automated data processing using punch cards was performed by tabulating machines designed by Hermann Hollerith.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated special-purpose analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. These became increasingly rare after the development of the programmable digital computer.
A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features of modern computers, such as the use of digital electronics (largely invented by Claude Shannon in 1937)[3] and more flexible programmability.

Defining one point along this road as "the first digital electronic computer" is exceedingly difficult. On 12 May 1941 Konrad Zuse completed his electromechanical Z3, being the first working machine featuring automatic binary arithmetic and feasible programmability (therefore the first digital operational programmable computer, although not electronic); other notable achievements include the Atanasoff-Berry Computer (shown working around Summer 1941), a special-purpose machine that used valve-driven (vacuum tube) computation, binary numbers, and regenerative memory; the secret British Colossus computer (demonstrated in 1943), which had limited programmability but demonstrated that a device using thousands of valves could be both made reliable and reprogrammed electronically; the Harvard Mark I, a large-scale electromechanical computer with limited programmability (shown working around 1944); the decimal-based American ENIAC (1946) — which was the first general purpose electronic computer, but originally had an inflexible architecture that meant reprogramming it essentially required it to be rewired.

The team who developed ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which has become known as the Von Neumann architecture (or "stored program architecture"). This stored program architecture became the basis for virtually all modern computers. A number of projects to develop computers based on the stored program architecture commenced in the mid to late-1940s; the first of these were completed in Britain. The first to be up and running was the Small-Scale Experimental Machine, but the EDSAC was perhaps the first practical version that was developed.

Valve (tube) driven computer designs were in use throughout the 1950s, but were eventually replaced with transistor-based computers, which were smaller, faster, cheaper, and much more reliable, thus allowing them to be commercially produced, in the 1960s. By the 1970s, the adoption of integrated circuit technology had enabled computers to be produced at a low enough cost to allow individuals to own a personal computer.

How computers work: the stored program architecture

While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the stored program architecture (sometimes called the von Neumann architecture). The design made the universal computer a practical reality.

The architecture describes a computer with four main sections: the arithmetic and logic unit (ALU), the control circuitry, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by bundles of wires (called "buses" when the same bundle supports more than one data path) and are usually driven by a timer or clock (although other events could drive the control circuitry).

Conceptually, a computer's memory can be viewed as a list of cells. Each cell has a numbered "address" and can store a small, fixed amount of information. This information can either be an instruction, telling the computer what to do, or data, the information which the computer is to process using the instructions that have been placed in the memory. In principle, any cell can be used to store either instructions or data.

The ALU is in many senses the heart of the computer. It is capable of performing two classes of basic operations. The first is arithmetic operations; for instance, adding or subtracting two numbers together. The set of arithmetic operations may be very limited; indeed, some designs do not directly support multiplication and division operations (instead, users support multiplication and division through programs that perform multiple additions, subtractions, and other digit manipulations). The second class of ALU operations involves comparison operations: given two numbers, determining if they are equal, or if not equal which is larger.

The I/O systems are the means by which the computer receives information from the outside world, and reports its results back to that world. On a typical personal computer, input devices include objects like the keyboard and mouse, and output devices include computer monitors, printers and the like, but as will be discussed later a huge variety of devices can be connected to a computer and serve as I/O devices.

The control system ties this all together. Its job is to read instructions and data from memory or the I/O devices, decode the instructions, providing the ALU with the correct inputs according to the instructions, "tell" the ALU what operation to perform on those inputs, and send the results back to the memory or to the I/O devices. One key component of the control system is a counter that keeps track of what the address of the current instruction is; typically, this is incremented each time an instruction is executed, unless the instruction itself indicates that the next instruction should be at some other location (allowing the computer to repeatedly execute the same instructions).

Since the 1980s the ALU and control unit (collectively called a central processing unit or CPU) have typically been located on a single integrated circuit called a microprocessor.

The functioning of such a computer is in principle quite straightforward. Typically, on each clock cycle, the computer fetches instructions and data from its memory. The instructions are executed, the results are stored, and the next instruction is fetched. This procedure repeats until a halt instruction is encountered.

The set of instructions interpreted by the control unit, and executed by the ALU, are limited in number, precisely defined, and very simple operations. Broadly, they fit into one or more of four categories: 1) moving data from one location to another (an example might be an instruction that "tells" the CPU to "copy the contents of memory cell 5 and place the copy in cell 10"). 2) executing arithmetic and logical processes on data (for instance, "add the contents of cell 7 to the contents of cell 13 and place the result in cell 20"). 3) testing the condition of data ("if the contents of cell 999 are 0, the next instruction is at cell 30"). 4) altering the sequence of operations (the previous example alters the sequence of operations, but instructions such as "the next instruction is at cell 100" are also standard).

Instructions, like data, are represented within the computer as binary code — a base two system of counting. For example, the code for one kind of "copy" operation in the Intel x86 line of microprocessors is 10110000 [4]. The particular instruction set that a specific computer supports is known as that computer's machine language. Using an already-popular machine language makes it much easier to run existing software on a new machine; consequently, in markets where commercial software availability is important suppliers have converged on one or a very small number of distinct machine languages.

More powerful computers such as minicomputers, mainframe computers and servers may differ from the model above by dividing their work between more than one main CPU. Multiprocessor and multicore personal and laptop computers are also beginning to become available.

Supercomputers often have highly unusual architectures significantly different from the basic stored-program architecture, sometimes featuring thousands of CPUs, but such designs tend to be useful only for specialized tasks. At the other end of the size scale, some microcontrollers use the Harvard architecture that ensures that program and data memory are logically separate.

Tuesday, April 18, 2006

Active Desktop - Enable/Disable

Active Desktop - Enable/Disable

The user is normally given the option of disabling Active Desktop through the
display properties. This tweak removes the ability to disable Active Desktop.

Open your registry and find the key below.

Create a new DWORD value named "ForceActiveDesktopOn" and set the value to "1"
to force the use of Active Desktop.

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

Value Name: ForceActiveDesktopOn

Data Type: REG_DWORD (DWORD Value)

Value Data: (0 = default, 1 = enabled)

* This tweak will remove the Active Desktop options from Settings on the
Start Menu.

Open your registry and find the key below.

Create a new DWORD value named "NoSetActiveDesktop", and set the new value to
equal "1" to enable the restriction or "0" to disable the restriction.

Note: This restriction can be used either on a user by user basis by adding it
to HKEY_CURRENT_USER or on a computer wide basis by adding it to
HKEY_LOCAL_MACHINE.

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

Value Name: NoSetActiveDesktop

Data Type: REG_DWORD (DWORD Value)

Value Data: (0 = disable restriction, 1 = enable restriction)


" This tweak allows you to have Active Desktop enabled, but to

restrict any changes to the settings "

Open your registry and find the key below.

Create a new DWORD value, or modify the existing value called 'NoActiveDesktopChanges'
set the value to equal '1' to enable the restriction.

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]

Value Name: NoActiveDesktopChanges

Data Type: REG_DWORD (DWORD Value)

Value Data: (0 = disable restriction, 1 = enable restriction)

" Features of the Windows Active Desktop can be selectively controlled by
modifying options in the Windows registry. Following the instructions in this
tweak "

Open your registry and find the key below.

Create a new DWORD value based on the options below, and set the new value to
equal "1" to enable the restriction or "0" to disable the restriction.

NoChangingWallpaper - Disable the ability to change wallpapers.

NoComponents - Disable components.

NoAddingComponents - Disable the ability to add components.

NoDeletingComponents - Disable the ability to delete components.

NoEditingComponents - Disable the ability to edit components.

NoCloseDragDropBands

NoMovingBands - retrict adjustments to desktop toolbars

NoHTMLWallPaper - only allow bitmaps (BMP) as wallpaper

Note: These restrictions can be used either on a user by user basis by adding it
to HKEY_CURRENT_USER or on a computer wide basis by adding it to
HKEY_LOCAL_MACHINE.

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop]

System Key: [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop]

Data Type: REG_DWORD (DWORD Value)

Value Data: (0 = disable restriction, 1 = enable restriction)

Wednesday, March 15, 2006

Cannot Start Windows XP if the System or Software Hive Is Missing or Damaged


When you try to start or restart your Windows XP-based computer, you may receive
one of the following error messages:

Windows XP could not start because the following file is missing or corrupt:
\WINDOWS\SYSTEM32\CONFIG\SYSTEM

Windows XP could not start because the following file is missing or corrupt:
\WINDOWS\SYSTEM32\CONFIG\SOFTWARE

To resolve this issue, use one of the following methods.
Use the Recovery Console Tool:

To restore a damaged registry hive, use the Recovery Console to restore the

backup copy of the hive from the Repair folder. The Repair folder contains a
copy of the system's registry hives that were created after the first successful
startup of Windows XP.

WARNING : Although data should not be affected by the following procedure, you
may need to restore changes you previously made to programs or system settings
since the first time you successfully started Windows XP.

To replace the damaged registry hive and restore the backup copy of the hive
from the Repair folder: Start your computer to the Recovery Console.

Determine if the file that is mentioned in the "Symptoms" section of this
article is present, and if it is, rename it:

In Recovery Console, change to the c:\Windows folder.

Type cd system32\config , and then press ENTER.

Type dir system , and then press ENTER.

If you cannot run the preceding command successfully (because the file is
missing), skip to step 3. If you can run the preceding command successfully,
type ren system system.bak , and then press ENTER.

NOTE : If the message that you received referred to the software file, replace
"system" with "software" in the preceding command. For example, you would type
ren software software.bak (instead of ren system system.bak ), and then press
ENTER.

Type copy c:\windows\repair\system , and then press ENTER.

NOTE : If the message that you received referred to the software file, replace
"system" with "software" in the preceding command. For example, you would type
copy c:\windows\repair\software (instead of copy c:\windows\repair\system ), and
then press ENTER.

You should receive a "One file copied" informational message. For additional

information about how to use Recovery Console during startup, click the article
number below to view the article in the Microsoft Knowledge Base:

Q307654 HOW TO: Install and Use the Recovery Console for Windows XP

IMPORTANT : If you encounter problems when you run the preceding commands, you
may need to use the Change Directory command ( cd ) one folder at a time before
you run the preceding commands. For example, type cd system32 , press ENTER,
type cd config , and then press ENTER.

Type exit , and then press ENTER to quit Recovery Console and restart the
computer.

Tuesday, February 14, 2006

Removing Invalid Entries in the Add/Remove Programs Tool

Start/Run/Regedit

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall

Each program listed in Add/Remove Programs has a subkey listed here. Locate the correct subkey for the program in question and right click it, then select Delete. You may want to choose Export, first, to export the key to a REG file. The REG file can be re-imported if you find you made a mistake.

You may have to contact the manufacturer of the program that you want to remove if you need to clean up the disk and registry entries. The procedure described in this section does not remove all the files and registry entries used by the program; it removes only the reference in the Add/Remove Programs tool.

Note: Other checkpoints to consider when trying to remove a program:

Check to see if the software/program is listed here: Start/Run/Regedit

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

1. Right click the Program's shortcut/Properties to gain the Target Path.

2. Go to Start/Run/Msconfig/Startup and make sure it is not listed or checked there. If so, uncheck it and remove the program listing from here: Start/Run/Regedit

For items that were in the Start menu, Programs, Startup folder:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupfolder. You'll find a subkey for each disabled item.

For items loaded from the Registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupreg. Again, you'll find a subkey for each disabled item.

Clear Disabled Items from Msconfig Startup (Line 148)
http://www.kellys-korner-xp.com/xp_tweaks.htm

3. Go to Windows Explorer/Tools/Folder Options/File Types. If the program file type is listed, either use Change or Delete.

4. Go to Start/Run/Regedit and navigate to this key: HKEY_CLASSES_ROOT\Applications. If the program is listed, right click, delete.

5. Go to Start/Run/Regedit and navigate to these keys:
HKEY_CURRENT_USER\Software and HKEY_LOCAL_MACHINE\SOFTWARE. If the program is listed, right click, delete.

6. Go to Start/Run/Regedit. Edit/Find and under Find What type in the program path gained from step one. From there either use Find next or F3.

7. Removing Invalid Entries in the Add/Remove Programs Tool
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

8. The Windows Installer CleanUp Utility can remove a program's Windows Installer configuration information.
http://support.microsoft.com/default.aspx?scid=kb;en-us;290301

9. Third Party: Displays the entries in the Add/Remove Programs list of Windows Registry, checks if each is valid, and uninstalls the selected program or removes the entry from the list. http://superwin.swmirror.com/adrmpro2.exe

10. You Cannot Reinstall a Program with the Add/Remove Programs Tool

Friday, January 06, 2006

NTLDR is missing, press any key to restart

The quick test to make sure your OS installation is still good is to create an MBR and NTLDR on a floppy disk and check your partitions, this disk will check many of the partitions for a working windows installation. Here are the instructions to do this:

1. Get a blank floppy (whatever is on it will be erased), and put it into a working computer.

2. Download fixntldr.exe onto a working computer

3. Run the fixntldr.exe file by double clicking it. Click OK to overwrite the blank floppy disc in the working computer, you should see some screens about writing a new floppy disk.

4. Do you remember if the folder you had your Windows installation in was named "Windows"? If you can't remember just keep going.

5. Put the new floppy you have just created into the computer that gets the NTLDR is missing error message, turn the broken computer off.

Using the boot disk in the computer with the "NTLDR is missing" error.

Start back up the broken computer with the floppy in the floppy drive. Once your computer gets past the BIOS screen your computer should try to access the floppy drive and you should see a black screen with white letters that says:

1ST TRY THIS seleccione esto primero
2ND TRY THIS essayez ceci en deuzieme
3RD TRY THIS wahlen Sie diesen Third
4TH TRY THIS selezioni questo fourth
5TH TRY THIS selecione este fifth
6TH TRY THIS seleccione este sexto
7TH TRY THIS essayez ceci en septieme
8TH TRY THIS wahlen Sie dieses achte
9TH TRY THIS selezioni questo nono
10TH TRY THIS selecione este decimo

(I threw in some Spanish / French / German / Italian / Portuguese for international flavor.)

This file is set up to automatically select the "1ST TRY THIS" choice after 30 seconds. Try it first, if it was the wrong selection, you will likely get one of these three errors:

1. Windows could not start because file "\system32\hal.dll was missing or corrupt

2. Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware. Please check the Windows documentation about hardware disk configuration and your hardware reference manuals for additional information.

3. I/O Error accessing boot sector file multi(0)disk(0)fdisk(0)\BOOTSECT.DOS

4. Immediate reboot

If you get the immediate reboot or some other weird error, try pressing F8 at the "1st Try This" selection screen, it will give you a prompt where you can select Safe Mode, and then try the "1st Try This" option again. Safe Mode is a special "minimal" version of Windows that doesn't load certain parts of the operating system that might have caused the problem.

One of the choices should eventually boot you back into Windows. (If you go all the way to option 10 and still get errors on startup, try changing boot.ini to windows.ini, then winnt.ini to boot.ini, and run through all 10 possibilities again.

Use windows to fix the boot files on the hard drive.

Once you get back into windows, try to change back whatever you were last doing and boot normally, it that doesn't work, go to the root of your C:\ drive and rename boot.ini to boot.ini.bak, ntldr to ntldr.bak, and ntdetect.com to ntdetect.com.bak, then copy the files that are on your floppy disk to the root of your C:\ drive (if you used the CD-ROM, download the fixntldriso.zip file and use the boot files from there) so that the files are on the root, like C:\ntldr C:\ntdetect.com C:\boot.ini. If it prompts you to overwrite a file, press "Yes". After they have been copied over, be sure to remove the "Read-Only" attribute from the properties of the files. (Right click on a file, choose properties, and uncheck the Read-Only box). Take the floppy out and reboot the computer (you should see the "1st Try This" menu, make the same selection you did before.

If you get back into Windows again, you can change that "1st Try This" menu by going into Start > Control Panel > System > Advanced tab > Startup and Recovery section, Settings button > System Startup; then change the "Default Operating System:" to the selection that worked for you, and change the box that says "Time to display list of operating systems" to however many seconds you want (usually 1 second). Click OK twice.

Sunday, December 18, 2005

Recovery Console in Windows XP

Recovery Console in Windows XP

Description of the Windows Recovery Console

This section describes the functionality and limitations of the Windows Recovery Console. The Windows Recovery Console is designed to help you recover when your Windows-based computer does not start properly or does not start at all.

When you use the Windows Recovery Console, you can obtain limited access to NTFS, FAT, and FAT32 volumes without starting the Windows graphical interface. In the Windows Recovery Console you can:

Use, copy, rename or replace operating system files and folders, Enable or disable services or devices from starting when you next start your computer, Repair the file system boot sector or the Master Boot Record (MBR), Create and format partitions on drives.

Note that only an administrator can obtain access to the Windows Recovery Console so that unauthorized users cannot use any NTFS volume. More Information.

To install the Recovery Console as a Startup Option

With Windows running, insert the Setup CD into your CD-ROM drive. Start/Run/X:i386\winnt32.exe /cmdcons. Follow the instructions on the screen.

Notes:

To run the Recovery Console, restart your computer and select the Recovery Console option from the list of available operating systems.

You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure.

To see the commands available on the Recovery Console, type help at the at the console prompt.

To start the computer and use the Recovery Console

From the Setup CD-ROM

Insert the Setup compact disc (CD) and restart the computer. If prompted, select any options required to boot from the CD.
When the text-based part of Setup begins, follow the prompts; choose the repair or recover option by pressing R. If you have a dual-boot or multiple-boot system, choose the installation that you need to access from the Recovery Console. When prompted, type the Administrator password. At the system prompt, type Recovery Console commands; type help for a list of commands, or help commandname for help on a specific command.

To exit the Recovery Console and restart the computer, type exit.

If you have already installed the Recovery Console

During Startup, select Recovery Console from the startup options menu. If you have a dual-boot or multiple-boot system, choose the installation that you need to access from the Recovery Console. When prompted, type the Administrator password. At the system prompt, type Recovery Console commands; type help for a list of commands, or help commandname for help on a specific command. To exit the Recovery Console and restart the computer, type exit.

Important Note: Because the Recovery Console is quite powerful, it is recommended for use only by advanced users or administrators.

To Delete the Recovery Console

Open My Computer.
Double-click the hard drive on which you installed the Recovery Console.
On the Tools menu, click Folder Options.
Click the View tab.
Click Show hidden files and folders, clear the Hide protected operating system files check box, and then click OK.
At the root directory, delete the \Cmdcons folder.
At the root directory, delete the file Cmldr.
At the root directory, right-click the Boot.ini file and then click Properties.
Clear the Read-only check box, and then click OK.
Open Boot.ini in Notepad, and remove the entry for the Recovery Console. It will look similar to this:
C:\cmdcons\bootsect.dat="Microsoft Windows Recovery Console" /cmdcons

Save the file and close it.

Modifying the Boot.ini file incorrectly may prevent your computer from restarting. Be sure to delete only the entry for the Recovery Console. Notes:

To open My Computer, double-click the My Computer icon on the desktop.
It is recommended that you change the attribute for the Boot.ini file back to read-only after you complete this procedure. You may also want to hide your system files again.


The commands available when using the Recovery Console are:
Attrib CD Chdir
Chkdsk Cls Copy
Del Delete Dir
Disable Diskpart Enable
Exit Expand Fixboot
Fixmbr Format Help
Listsvc Logon Map
MD Mkdir More
Rd Ren Rename
Rmdir Type Systemroot

Attrib: Changes the attributes of a file or directory.
Batch: Executes the commands specified in the text file.
ChDir (Cd): Displays the name of the current directory or changes the current directory.
Chkdsk: Checks a disk and displays a status report.
Cls: Clears the screen.
Copy: Copies a single file to another location.
Delete (Del): Deletes one or more files.
Dir: Displays a list of files and subdirectories in a directory.
Disable: Disables a system service or a device driver.
Diskpart: Manages partitions on your hard drives.
Enable: Starts or enables a system service or a device driver.
Exit: Exits the Recovery Console and restarts your computer.
Expand: Extracts a file from a compressed file.
Fixboot: Writes a new partition boot sector onto the system partition.
Fixmbr: Repairs the master boot record of the partition boot sector.
Format: Formats a disk.
Help: Displays a list of the commands you can use in the Recovery Console.
Listsvc: Lists the services and drivers available on the computer.
Logon: Logs on to a Windows 2000 installation.
Map: Displays the drive letter mappings.
Mkdir (Md): Creates a directory.
More: Displays a text file.
Rename (Ren): Renames a single file.
Rmdir (Rd): Deletes a directory.
Set: Displays and sets environment variables.
Systemroot: Sets the current directory to the systemroot directory of the system you are currently logged on to.
Type: Displays a text file.

This list can be obtained in the Console by typing "help" without the quotes.

A Discussion About the Bootcfg Command and Its Uses

The bootcfg command is a Microsoft Windows XP Recovery Console command that manipulates the Boot.ini file. This command has a function that can scan your hard disks for Microsoft Windows NT, Microsoft Windows 2000, and Windows XP installations, and then add them to an existing Boot.ini file or rebuild a new Boot.ini file, if one does not exist. The bootcfg command enables additional Boot.ini file parameters to be added to existing or new entries.

To use the bootcfg command, start the Recovery Console with the Windows XP CD-ROM, and then click Recovery Console. Or, install the Recovery Console locally, and then select the command from the Boot menu. More Information.

How to Boot Windows Preinstall Environment from a Hard Disk

This section describes how to configure the Windows Preinstall Environment (WinPE) to boot from a hard disk.

NOTE: More than likely the supported methods to boot WinPE (by means of a CD-ROM or from a Remote Installation Services (RIS) server) are the most commonly used methods. The method that is described in this article is provided for
informational purposes. More Information.

Access Floppy Drive from Recovery Console

To enable write access to floppies from within the R.C., click Start, Programs, Administrative Tools, Local Security Policy. Under Local Policy, Security Options, double-click "Recovery Console: Allow floppy copy and access to all drives and all folders." Select Enabled, then click OK.

Note: The following steps may also be necessary:

"After you enable the security policy, it must be applied (possibly across the domain) before becoming the effective policy on the local computer. This is necessary before the set command is truly enabled and available for use during a Recovery Console session. You can run the following command to force a refresh of the local computer's policy after performing the policy change listed above: secedit /refreshpolicy machine_policy

After the local policy is refreshed and the enabled Recovery Console security policy is in effect, you should be able to start Recovery Console and use the set command to enable any of the four environment options."

In the Recovery Console, you must then type: set AllowRemovableMedia = TRUE

Accessing Other Folders in Recovery Console

This security policy will also access to files and folders other than the defaults (normally access is restricted to \winnt and \cmdcons). To enable access to other folders, simply boot to the Recovery Console command prompt and type: set AllowAllPaths = true

You will then be able to access other files and folders on your computer. Please keep in mind that this is a potential security problem, and that you should be careful to restrict physical access to computers that are configured in this way.

Friday, July 15, 2005

Windows Update Site Problems

To protect your computer, you need the proper updates for your operating system. This is Number Two on the list of "Must do" to protect your computer.

Any operating system must be kept up to date. Without the updates, your computer will become increasingly more vulnerable to new threats.
Some of these threats are made possible by weaknesses discovered in Windows after Windows was released. Other weaknesses became apparent as new technology creates a weakness where there was none before.
Windows has made it easy to keep up to date
You can perform Windows Update automatically, prompted or manually.

Windows ME, 2000 & XP:
To set Windows Update on automatic (recommended for most home users)
Right click "My Computer"
Click "Properties"
Click "Automatic Updates"
Place check in "Keep my computer up to date"
Also place a bullet in "Automatically download the updates"
NOTE: Be sure your computer is powered on the day/time you set.
To set Windows Update to prompt for the updates choose one of the other two bullets on that page.
To manually update:
Start/All Programs/Windows Update
Follow the prompts.

Windows 9X:
Double click "My Computer"
Double click "Scheduled Tasks"
Double click "Windows Critical Update Notification"
You can make selections as desired.
If the option is not available install Windows Critical Update Notification:
1. Go here:
http://windowsupdate.microsoft.com
2. Click "Scan for updates"
3. On the left side click "Windows 98 and Windows 98 Second Edition"
4. Click "Add" by "Windows Critical Update Notification recommended update"
5. Click "Review and install updates"
6. Click "Install Now"

You should install ALL Critical Updates.
Install the Recommended Updates that you have determined apply to you.
Get the drivers directly from the manufacturer

If you have not updated in a while, you may have a lot of updates.
Install Service Packs first and by itself
Reboot
Install updates no more than three at a time.
Reboot
Install next three.

Don't forget to check for and install updates for other software such as Microsoft Office.

Saturday, May 14, 2005

Repair the Boot Sector

If XP won't start it may be due to a damaged boot sector or a missing or corrupt ntldr or ntdetect.com files.

To replace damaged ntldr and ntdetect.com you can copy fresh files from the XP CD using the COPY command. Boot with the XP CD and enter the Recovery Console (as above). At the Command Prompt type the following (where "X" is your CD-Rom drive letter) allowing the files to overwrite the old files
COPY X:\i386\NTLDR C:
COPY X:\i386\NTDETECT.COM C:

To repair a damaged Boot Sector at the command prompt type FIXBOOT and press Enter. Then answer "Y"

Thursday, March 10, 2005

How To Create a Boot Disk to Start Windows XP

Create a Windows startup disk when you first install Windows on the computer. This disk is different from an MS-DOS startup disk. Unlike MS-DOS, the whole Windows operating system cannot fit on one floppy disk. A Windows startup disk contains only the files that you must have to start the operating system with the remainder of the Windows system files installed on the hard disk drive. To create the startup disk, follow these steps:
1.Insert a blank floppy disk in drive A, and then format the disk by using Windows XP.
2.From the root folder of the system partition of your hard disk drive (for example, C:\-), copy the following files to the floppy disk:
Boot.ini
NTLDR
Ntdetect.com
You may have to remove the hidden, system, and read-only attributes from the files.
3.Restore the hidden, system, and read-only attributes to the files on your hard disk if you removed these attributes.
4.If the Bootsect.dos file or the Ntbootdd.sys file resides in the system partition, repeat steps 2 through 4 to copy these files to the boot disk.

Wednesday, January 19, 2005

How to access Last Known Good Configuration

Reboot your computer while holding down the F8 Key. At the Advanced Options Menu select Last Known Good Configuration.

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Reboot your computer while holding down the F8 Key. At the Advanced Options Menu select the option for Safe Mode and press Enter.