CON: Tutorial to create folder with name CON
Simple ppl dont know why they cant create File named with "CON"? Very few know that they can still create it someway.. but why are they supposed to do exactly like that.. Now, After reading this tutorial, you will become one of the rest. Not only CON, we cannot create any of these:
CON, PRN, AUX, CLOCK$, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9 and more The reason is that con, prn, lpt1..lpt9, etc are underlying devices from the time dos was written. so if u r allowed to create such folders, there will be an ambiguity in where to write data when the data is supposed to go to the specified devices. In other words, if i want to print something, internally what windows does is -- it will write the data to the folder prn (virtually u can call it a folder, i mean prn, con, etc are virtual folders in device level). So if we are able to create con folder, windows will get confused where to write the data, to virtual con folder or real one. So Now, Try this...
C:\> md \\.\x:\con
Note: x: repersent the Drive letter where want to create. (it may be C:, D: and So on)
Now, Open My Computer and browse through the path where you created CON folder ... Surprising.. ?? Yeah.. you have created it successfully..
Now, try to delete the folder from My computer
OOPS!!! You cant delete it...
Now, try this in command prompt console
C:\> rd \\.\x:\con
You Did it
For More info You can Click on http://support.microsoft.com
Creating a Database File
Before Creating Database in fox pro we should understand
Data type. Various type of data type used according to requirement-
Data type
|
Size (bytes)
|
Description
|
Range
|
Character
|
1 to 254
|
Any Characters and text abb- C
|
ex- a-z, ?, # etc
|
Numeric
|
1 to 20
|
Integer and fraction , abb.-N
|
- .9999999999E+19 to .9999999999E+20
|
Currency
|
8 bytes
|
Amounts, abb.- Y
|
- 922337203685477.5807 to 922337203685477.5807
|
Date
|
8 bytes
|
Date entry, Abb.- D
|
|
Datetime
|
8 bytes
|
Date with time, Abb.- T
|
Time in 00:00:00 to 11:59:59
|
Logical
|
1 bytes
|
Logical entry, Abb.-L
|
Only .T. and .F.
|
Double
|
8 bytes
|
More accurate with fraction, abb.-B
|
- .9999999999E+19 to .9999999999E+20
|
Integer
|
4 bytes
|
Space saver data type for numeric, abb.- I
|
-2,147,483,647 to 2,147,483,647
|
Float
|
1-20
|
Same as numeric, abb-F
|
- .9999999999E+19 to .9999999999E+20
|
Memo
|
4 bytes
|
Used to store more information in foxpro it is not saved in dbf file.
It is saved seperatly in FPT file, abb.-My name
|
Any text, symbol
|
General
|
4 bytes
|
Closely same as memo and its content is housed iin FPT file, abb- G
|
Any OLE document
|
Principal file types related to database-
1.
DBF-( Database file)
it is primary extension of foxpro. It is main storage file of database.
2.
DBC- (Database
container) Contains information aobut data file indexes, relationaships and
other aspects of a database. It is sometime called database dictionary.
3.
DCT- (Database
Container Text) stores the code and other text material for DBC file this is
not directly readable by FoxPro.
4.
FPT- (FoxPro Text)
it can store large quantities of text, picture.
Here general data of general field and memo fields are stored.
5.
CDX-(CompounD indeX)
Contain the indexes or DBF file.
6.
BAK- (BAcK up file)
it is created for DBF file.
7.
PRG- (PRoGram file)
it contain the source code of program
8.
SCX-(Screen File) it
store the form.
9.
FRX-(Report file) it
store the report.
Creating
Database
Ø There are two method to create database in
foxpro-
1.
Type CREATE in command window. in open box type file name -- ok
2.
File menu—New-
-A box will open here select Table/DBF
radio button
-ok
·
In
both case a box will open –
·
Here
define the structure according to requirement- Such as field name data type
it’s range
Field Name
|
Data type
|
Width
|
Name
|
Character
|
20
|
Location
|
Character
|
15
|
Address
|
Character
|
15
|
PIN
|
Character
|
8
|
Mob
|
Character
|
10
|
·
Ok
·
A
box will appear that say input record or not choose yes
·
A
window will appear hear each field name will show in separate row
·
Fill
the record one by one
·
When
finish press Esc button
Name
|
Location
|
Address
|
PIN
|
Mob
|
Tony
|
Station road
|
Barh
|
803213
|
98765778
|
Pyush
|
Bedhna
|
Barh
|
803213
|
99766666
|
Swati
|
Station road
|
Barh
|
876655
|
99877666
|
Kundan
|
GulabBagh
|
Mokama
|
876555
|
08877666
|
Nitish
|
Fathuha
|
Patna
|
876555
|
98766666
|
Note :
1.
don’t
use Numeric type data when not necessary, such as In PIN we can use Number data type but it
require more space in memory hence character is used.
2.
When
we use file menu – new then file will created with untitled.dbf
extension
Command:
1. CREATE: it provide facility to define structure of Database file.
Syntax: CREATE <Path with file name>
Ex:
CREATE address.dbf (create database file address in
current directory)
CREATE d:\address.dbf (create database
file in d: drive)
CREATE d:\my\address.dbf (create database file in directory of
drive d:)
FoxPro 2.6 : Introduction
Fox pro is one of the best Data base Management Software (DBMS) application for PC.- First DBMS for the PC was developed by ASSTON-TATE in 1979-80 that was called dBASE II. Then the company introduced the updated version of dBASE II in 1984 that was called dBASE III. Later company was developed enhanced version of dBASE III called dBASE III plus.
- Arround 1990, Fox Software, Inc. developed a new Programming language FoxBASE become the another very popular DBMS software and share DBMS market with dBASE. FoxBASE was next reanamed as FoxPro and updated for most powerful it was compatible with dBASE III and very userfriendly.
- FoxPro is not only DBMS but more than it and popularly called RDBMS package.
- Initially it was developed for DOS based environment. But after version 2.6 it is also available for windows and other enviornmet.
- Around 1992, Fox Software, Inc. was merged with Microsoft Corporation and released FoxPro 2.6. Soon Microsoft update it and renamed as Visual FoxPro (VFP). Microsoft next released many version some of them are- VFP 5.0, VFP 7.0, VFP 9.0. In 2007 Microsoft announced no anymore version of VFP will released next and development was closed. Latest version of VFP is Visual FoxPro 9.0.
- Using FoxPro we can easily handle Database of small organization or company.
System Requiremet for Fox Pro 2.5 and 2.6
- Processor- 80386 or above
- Memory- 3-4 MB
- Disk Space- 20 MB
- Operating System –Windows, Dos
- CD or FD Drive
Steps to Start
FoxPro
Version to Version Steps of launching FoxPro
may be changed but overall steps are following-
1.
Find the location
of directory where fox pro was installed-
A. DOS-
Ø
Use
CD command to find ex- type CD
C:\FOXPROW
Ø Type FoxPro and Enter
B. Windows-
Ø find the location using my computer
Ø double click on FOXPROW.exe
FoxPro 2.6 For Windows
FoxPro 2.5 For DOS
When
FoxPro window will open then it looks like above
Menu Bar (Pad) :
In any program many options and commands are available. All these
commands are grouped and menu and the place where all these are stay called
menu bar. In DOS based environment it is called Menu Pad. We use menu using
mouse or keyboard-
a.
To select menu form keyboard press ALT or
F10 button. then a character of menu will highlighted when we press this key
form keyboard that menu fly out will open. Such as when want to open File menu
we press ALT then F.
b.
To select menu from mouse move your mouse all
menu that want to open and then click.
Command
Window: In Fox pro Command Window is default available at right side. We
use it to entering the command and directly perform task instead of using mouse
and menu. It is faster way to perform operation. Mostly options can be handled
using command window but some are not performed through where some are not
performed using mouse.
Some time
Command Window not appear then use any of the following-
1.
Window menu- command
2.
Ctrl+F2
Status
Bar: Status Bar available at bottom of FoxPro window . it show the status
such as – EOF(End of File), Open database. It also display help about what task
performed by this command when cursor is placed on any option.
Time Travel: is it possible
In Metaphysics: Yes, time travel already is a reality. If time travel were not a reality, how then did we get suspended here in this temporal dimension of time and space? Time exists as a polar opposite to eternity, an opposite and equal reaction to time. This is evident when we try to measure the immeasurable universe.
Time travel in our perception would imply rifts in the space-time continuum, causing a paradox, much like that seen in the movies "Back to the Future" and "Minority Report". Time travel is a reality according to Einstein's theory of relativity, where the faster an object travels, the slower time goes. Simply put, this is only possible with exponential proportions of speed, resulting in an explosive force that causes the matter traveling to turn into energy at the speed of light squared--this is to say that matter is what is traveling through time and space.
If time travel ever became a reality for people, wouldn't we already known it by the rifts being caused? Let's say 1,000 years from now someone comes back to this time or to a time before this; we certainly would have historical records of the person that traveled through time; because they may even be pictured or written in history books!
In the Bible: Apparently, time travel must be possible in order for the Bible to stand true, because the religious leaders said, "We are the children of Abraham." And Jesus responded, "I tell you the truth, before Abraham was, I AM." In a manner that truly defies space and time. In this case, this man is, was, and will always be the timeless man who defies the laws of nature; also, in order for people to see the future and write it down as prophecy, time travel must therefore be possible for this to work.
Changing the events of prophecy, such as Nineveh with Jonah predicting their doom, is also apparent. This city turned to God and the prophecy of doom was taken back, and they were forgiven. This idea gives us a paradox of what would have happened had they not turned to God and the city was destroyed; certainly some people alive today would have then not been born! Time travel would therefore be too dangerous for us humans to play with.
In Physics: It is an observation that two watches synched to exactly the same time, will show variations to the thousandth of a second when one watch is sent with a pilot at incredible speeds for a set duration on a fighter jet. However, this is barely measurable or even notable in our standards of "time." Nevertheless, if you had a hypothetical time machine, you could travel at a great speed and come back to earth thousands of years later, and only minutes would have passed in your relative dimension of "time." (But you'd have to travel precisely to the location earth would be in those thousands of years later... since earth is traveling through space! It's a long shot).
Einstein proved with his theory of relativity that time travel is possible, but it's only scientifically proven to be able to travel forward in time.
In conclusion, the only historical evidence of significant time travel is recorded in the Bible, since Jesus must have that power in order to be who he claimed to be--and in order for the prophets to obtain knowledge of the future to precision. This brings many questions to mind about paradoxes and destiny.
In the television series "Heroes", Hiro can travel through time and space, even stop time--this is an interesting concept for those who wish to change the past or see what the future holds.
Answer:
Answer1, two parts:
a) Time travel into the past probably never will be, but if it does happen, it will be only possible to "watch", and not interact or change things. Although this has not yet been proven, there are plenty of logical paradoxes that have been thrown up by time travel thought experiments that should convince us that this is the case.
b) Time travel into the future is possible now. Travelling through space at high speeds means you also travel through time as well, although you only move forwards in time by small amounts unless your speed approaches that of light. The astronauts that went to the moon travelled forwards in time by a few seconds, i.e. the atomic clocks they took with them slowed by a few seconds, and the astronauts aged a few seconds less than they would have on earth.
The answer 2 below is not incorrect (and this answer does not contradict it) - it's just that the further forwards in time you want to go and the faster you want to get to that future, time both get exponentially more difficult and expensive, because the power required gets exponentially great the faster in space you go because your mass increases exponentially towards infinity. If a cheap source of power is found to propel an ordinary space ship towards light speed, it would take a long time to get near to light speed, then time travel forwards will become commonplace.
Answer 2: No, TIME TRAVEL IS NOT POSSIBLE.
According to Einstein, time travel is not possible. We know that E=M(C*C). That is Energy = Mass into square the speed of light in vacuum speed of light in vacuum.
Suppose we invent a machine for time travel and as we reach the speed of light, think of the energy needed to move the machine forward.
i.e.: E=M(C*C)
As the speed increases, the energy required to move the machine forward also increases and it is directly proportional to the fuel required as we near the speed of light; the energy required becomes nearly infinity and the fuel required to push the machine forward also nears infinity. But, the resources available right now in finite, so logically, time travel is not possible.
Answer 3: Food for thought.
I recall news announcements a few years back about a spaceship that was being built. It was past the theory of warping space to be able to travel to Mars, I think, in only hours. I seem to recall it was a European country?. If true perhaps this will mean time travel is indeed likely.
There was an article on newscientist.com that described this, but has now been removed it seems. It was based on something called a Z particle. And it is USA not Europe sorry.
After all, what man dreams today is tomorrows reality.I think we all are travellers in time. Time and space, as I see it are being created at the border of the known universe. The bigger the universe becomes, the more space is created. In order to travel through space time is required. We think of speed as distance per time. I would like to turn this upside down and make time per distance of it. Now if one would like to travel faster than time, one would have to travel at less than zero seconds per distance! This implicates back in time. As E equals MC square, the energy added to increase speed would be converted to mass. I don't think time travelling is practicable.
The answer above is practical. Talking more, it is actually possible to travel time. Relativity claims that time is another dimension, so like any other dimension it is possible to break the barrier of time too. The theory states that anything faster than light can travel time. But again the problem is the theory itself. It states (by equation E=MC2) that as the speed tends to increase the mass required to keep the speed increases and proportionately the energy required to power the body too increases. Thus by the speed of light the mass turns infinite and thus the energy turns infinite too. It is impossible to achieve infinite energy thus it is impossible to travel time. Ha, ha, ha, what a catch to the theory right. But the law doesn't stop using Tachyons which always travel faster than light. But Tachyons can only be used for information.
What Is a Hacker?
The Jargon File contains a bunch of definitions of the term "hacker", most having to do with technical adeptness and a delight in solving problems and overcoming limits. If you want to know how to become a hacker, though, only two are really relevant.
There is a community, a shared culture, of expert programmers and networking wizards that traces its history back through decades to the first time-sharing minicomputers and the earliest ARPAnet experiments. The members of this culture originated the term ‘hacker’. Hackers built the Internet. Hackers made the Unix operating system what it is today. Hackers run Usenet. Hackers make the World Wide Web work. If you are part of this culture, if you have contributed to it and other people in it know who you are and call you a hacker, you're a hacker.
The hacker mind-set is not confined to this software-hacker culture. There are people who apply the hacker attitude to other things, like electronics or music — actually, you can find it at the highest levels of any science or art. Software hackers recognize these kindred spirits elsewhere and may call them ‘hackers’ too — and some claim that the hacker nature is really independent of the particular medium the hacker works in. But in the rest of this document we will focus on the skills and attitudes of software hackers, and the traditions of the shared culture that originated the term ‘hacker’.
There is another group of people who loudly call themselves hackers, but aren't. These are people (mainly adolescent males) who get a kick out of breaking into computers and phreaking the phone system. Real hackers call these people ‘crackers’ and want nothing to do with them. Real hackers mostly think crackers are lazy, irresponsible, and not very bright, and object that being able to break security doesn't make you a hacker any more than being able to hotwire cars makes you an automotive engineer. Unfortunately, many journalists and writers have been fooled into using the word ‘hacker’ to describe crackers; this irritates real hackers no end.
The basic difference is this: hackers build things, crackers break them.
If you want to be a hacker, keep reading. If you want to be a cracker, go read the alt.2600 newsgroup and get ready to do five to ten in the slammer after finding out you aren't as smart as you think you are. And that's all I'm going to say about crackers.
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