Sufi Infotech

18/12/2018

Nawab Bahadur Road Paschim Darwaza Patna City

15/06/2017

Why to use any folder-locking software when your simple text editor, Notepad can lock your folders? To use this Notepad tricks, follow these steps:

Open Notepad
Copy the following code:
OFF
title Folder Private
if EXIST “Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}” goto UNLOCK
if NOT EXIST Private goto MDLOCKER
:CONFIRM
echo Are you sure you want to lock the folder(Y/N)
set/p “cho=>”
if %cho%==Y goto LOCK
if %cho%==y goto LOCK
if %cho%==n goto END
if %cho%==N goto END
echo Invalid choice.
goto CONFIRM
:LOCK
ren Private “Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}”
attrib +h +s “Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}”
echo Folder locked
goto End
:UNLOCK
echo Enter password to unlock folder
set/p “pass=>”
if NOT %pass%== techgyd.com goto FAIL
attrib -h -s “Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}”
ren “Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}” Private
echo Folder Unlocked successfully
goto End
:FAIL
echo Invalid password
goto end
:MDLOCKER
md Private
echo Private created successfully
goto End
:End

05/06/2012

Promotion

computer science education

30/01/2012

History of Operating Systems
An operating system (OS) is a software program that manages the hardware and software
resources of a computer. The OS performs basic tasks, such as controlling and allocating memory,
prioritizing the processing of instructions, controlling input and output devices, facilitating
networking, and managing files.
The first computers did not have operating systems. However, software tools for managing
the system and simplifying the use of hardware appeared very quickly afterwards, and gradually
expanded in scope. By the early 1960s, commercial computer vendors were supplying quite
extensive tools for streamlining the development, scheduling, and ex*****on of jobs on batch
processing systems. Examples were produced by UNIVAC and Control Data Corporation, amongst
others.
Through the 1960s, several major concepts were developed, driving the development of
operating systems. The development of the IBM System/360 produced a family of mainframe
computers available in widely differing capacities and price points, for which a single operating
system OS/360 was planned (rather than developing ad-hoc programs for every individual model).
This concept of a single OS spanning an entire product line was crucial for the success of
System/360 and, in fact, IBM's current mainframe operating systems are distant descendants of this
original system; applications written for the OS/360 can still be run on modern machines. OS/360
also contained another important advance: the development of the hard disk permanent storage
device (which IBM called DASD). Another key development was the concept of time-sharing: the
idea of sharing the resources of expensive computers amongst multiple computer users interacting
in real time with the system. Time sharing allowed all of the users to have the illusion of having
exclusive access to the machine; the Multics timesharing system was the most famous of a number
of new operating systems developed to take advantage of the concept.
Multics, particularly, was an inspiration to a number of operating systems developed in the
1970s, notably Unix. Another commercially-popular minicomputer operating system was VMS.
The first microcomputers did not have the capacity or need for the elaborate operating systems that
had been developed for mainframes and minis; minimalistic operating systems were developed.
One notable early operating system was CP/M, which was supported on many early
microcomputers and was largely cloned in creating MS-DOS, which became wildly popular as the
operating system chosen for the IBM PC (IBM's version of it was called IBM-DOS or PC-DOS), its
successors making Microsoft one of the world's most profitable companies. The major alternative
throughout the 1980s in the microcomputer market was Mac OS, tied intimately to the Apple
Macintosh computer.
By the 1990s, the microcomputer had evolved to the point where, as well as extensive GUI
facilities, the robustness and flexibility of operating systems of larger computers became
increasingly desirable. Microsoft's response to this change was the development of Windows NT,
which served as the basis for Microsoft's entire operating system line starting in 1999. Apple rebuilt
their operating system on top of a Unix core as Mac OS X, released in 2001. Hobbyist-developed
reimplementations of Unix, assembled with the tools from the GNU project, also became popular;
versions based on the Linux kernel are by far the most popular, with the BSD derived UNIXes
holding a small portion of the server market.
The growing complexity of embedded devices has a growing trend to use embedded
operating systems on them

20/01/2012

CHARACTERISTICS OF COMPUTER
Speed: As we know that computer can work very fast. It takes only few seconds for calculations that we take hours to complete. Do you know our small computer can finish this work in few seconds? The weather forecasting that you see every day on TV is the results of compilation and analysis of huge amount of data on temperature, humidity, pressure, etc. of various places on computers. It takes few minutes for the computer to process this huge amount of data and give the result. we will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second. Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nano-second (10-9 part of a second). From this we can imagine how fast our computer performs work.

Accuracy : The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

Diligence: A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

Versatility: It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.

Power of Remembering: Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.

No IQ: Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can.

No Feeling: It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.

17/01/2012

The newspaper adverts scream out prices, and include seemingly meaningless abbreviations such as MHz, ATA-100, DDR, XGA. Do you know what these buzzwords really mean? Does anyone?
The PC may be the single most important tool for many workers, but because it is often purchased in a high street camera store or even a supermarket, it is often treated as a commodity item, almost a ‘white good’ such as a fridge, freezer or microwave.
First the good news. There are no bad Personal Computer systems. The least powerful system available today is better than the most expensive system of a few years ago. High quality components are produced in such large numbers at such low prices, that there is no profit building substandard systems.
The bad news is that the process doesn’t stop, and the most expensive or most powerful system you buy today will be (practically) obsolete next year.
If you want to know how a PC works and what all the jargon means, this section will attempt to answer your questions. No technical background is assumed, and even very complex issues will be explained in terms that everyone can understand.
Who Made It?
Your computer wasn’t made by the company from which you bought it. If you buy a car from Ford, you expect the frame, engine, transmission, generator, and other parts to come from Ford or at least be built to Ford specifications. That isn’t how the computer industry works. The companies that sell computers and whose names you know, such as Dell, Gateway, IBM, and Compaq, don’t make any of the important parts. Instead, they assemble a computer from parts made by other companies.
Your computer was really made by companies such as Asus, Abit, ATI, and AMD. This is really an international business with companies scattered around the world. They are not scattered uniformly. For reasons that are not clear, different countries seem to specialize in particular parts. The US companies build the CPU (Intel, AMD). The motherboard comes from Taiwan (Asus, Abit, Shuttle, MSI, ...). Disks come from Singapore or Indonesia (Seagate, Western Digital, IBM, Maxtor). Memory most often comes from Korea. The external case and the power supply come from any of a dozen Chinese companies.
You can buy the components from any number of sites on the internet and assemble a computer yourself, but you won’t save any money this way. The big computer makers buy parts in lots of a thousand, packaged in bulk
Personal Computer Hardware

17/01/2012

information

computer science education

14/01/2012

Most modern operating systems employ a method of extending RAM capacity, known as "virtual memory". A portion of the computer's hard drive is set aside for a paging file or a scratch partition, and the combination of physical RAM and the paging file form the system's total memory. (For example, if a computer has 2 GB of RAM and a 1 GB page file, the operating system has 3 GB total memory available to it.) When the system runs low on physical memory, it can "swap" portions of RAM to the paging file to make room for new data, as well as to read previously swapped information back into RAM. Excessive use of this mechanism results in thrashing and generally hampers overall system performance, mainly because hard drives are far slower than RAM.

14/01/2012

The two main forms of modern RAM are static RAM (SRAM) and dynamic RAM (DRAM). In static RAM, a bit of data is stored using the state of a flip-flop. This form of RAM is more expensive to produce, but is generally faster and requires less power than DRAM and, in modern computers, is often used as cache memory for the CPU. DRAM stores a bit of data using a transistor and capacitor pair, which together comprise a memory cell. The capacitor holds a high or low charge (1 or 0, respectively), and the transistor acts as a switch that lets the control circuitry on the chip read the capacitor's state of charge or change it. As this form of memory is less expensive to produce than static RAM, it is the predominant form of computer memory used in modern computers.
Both static and dynamic RAM are considered volatile, as their state is lost or reset when power is removed from the system. By contrast, Read-only memory (ROM) stores data by permanently enabling or disabling selected transistors, such that the memory cannot be altered. Writeable variants of ROM (such as EEPROM and flash memory) share properties of both ROM and RAM, enabling data to persist without power and to be updated without requiring special equipment. These persistent forms of semiconductor ROM include USB flash drives, memory cards for cameras and portable devices, etc. As of 2007, NAND flash has begun to replace older forms of persistent storage, such as magnetic disks and tapes, while NOR flash is being used in place of ROM in netbooks and rugged computers, since it is capable of true random access, allowing direct code ex*****on.
ECC memory (which can be either SRAM or DRAM) includes special circuitry to detect and/or correct random faults (memory errors) in the stored data, using parity bits or error correction code.
In general, the term RAM refers solely to solid-state memory devices (either DRAM or SRAM), and more specifically the main memory in most computers. In optical storage, the term DVD-RAM is somewhat of a misnomer since, like CD-RW, a rewriteable DVD must be erased before it can be rewritten.

14/01/2012

An early type of widespread writable random-access memory was magnetic core memory, developed from 1955 to 1975, and subsequently used in most computers up until the development and adoption of the static and dynamic integrated RAM circuits in the late 1960s and early 1970s. Before this, computers used relays, delay line/delay memory, or various kinds of vacuum tube arrangements to implement "main" memory functions (i.e., hundreds or thousands of bits), some of which were random access, some not. Drum memory could be expanded at low cost but retrieval of non-sequential memory items required knowledge of the physical layout of the drum to optimize speed. Latches built out of vacuum tube triodes, and later, out of discrete transistors, were used for smaller and faster memories such as random-access register banks and registers. Prior to the development of integrated ROM circuits, permanent (or read-only) random-access memory was often constructed using semiconductor diode matrices driven by address decoders, or specially wound core memory planes.

14/01/2012

Random access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in bursts, although the name DRAM / RAM has stuck. However, many types of SRAM, ROM, OTP, and NOR flash are still random access even in a strict sense. RAM is often associated with volatile types of memory (such as DRAM memory modules), where its stored information is lost if the power is removed. Many other types of non-volatile memory are RAM as well, including most types of ROM and a type of flash memory called NOR-Flash. The first RAM modules to come into the market were created in 1951 and were sold until the late 1960s and early 1970s.

13/01/2012