Saturday, March 25, 2006

XML by David Hozner : notes chapter 1

Main features:
1. Easy Data Handling
2. Customizing Markup Language
3. Self Describing Data
4. Structured (well-formed) & Integrated (Valid) data

Well formed: each element must be nested properly within any enclosing element.

Valid : Whether the XML document complies with the associated DTD.

DTD : Data type definition. DTDs can be stored in a separate file or in the document itself using a element.

XML parsing instructions start with "< ?" & close with "? >"

XML Tags : Starts with a letter or '_' and may contain letters, digits, underscores, dots (.) or hyphen (-) but no spaces.

Most browsers check for well-formedness but few check for validity.

The most powerful use of XML is to parse the XML document and to break it down into component parts. These component parts can then handling them in a customized way.

CSS : Cascading Style Sheet
XSL : Extensible Style Language
DOM : Document Object Model
CML : Chemical Markup Language (customized markup language using XML)
XHTML : Extensible Hyper Text Markup Language

.xul extension is used for XML based user interface language document.

XML Parsers:

XML4J : XML for Java by IBM Alphaworks. Conforms well to W3C standards. It is written in Java so it connects well to Java code. Download from

SAX : Simple API for XML

SXP : Silfide XML parser. It is a complete XML API in Java.

The Microsoft parser used in Internet Explorer is implemented as a COM component and can be found at

Java standard Extension for XML : A java package for XML.


CSS : it can set format & placement of elements.

XSL : it can reorder elements in a document, change them entirely, display some but hide others, select style based not just on elements but also element attributes, select style based on element location and so on.

XSL : XSL transformations
XSL formatting objects

XLINK : more powerful than simple hyperlink, these can be bi-directional as well as multi-directional &

sophisticated enough to point to the nearest mirror site from which a resource can be fetched.

XPOINTERS : points to a part in the document. These are smart enough to point to a specific element or to nth

occurance of the element, or to the first child element of any element & so on.


ASCII : 1 byte/256 codes : UTF-8
Unicode : 2 Bytes/64K codes : UTF-16 or UCS-2 or ISO-10646-UCS-2
UCS (Universal Character System): 4 Bytes/2 billion codes : UCS-4 or ISO-10646-UCS-4

One can write a document in local language and then use a translator to convert the same into Unicode.

To insert a particular symbol insert its Unicode with "&#". for example to insert a
π with Unicode value "03c0" in hexadecimal use &# x03c0;

List of Character Set at Internet Assigned Number Authority (IANI)

Java program to convert ASCII to unicode (found in Java SDK) :
C:/ native2ascii file.txt file.uni
It can also convert to other codes besides unicode.

XML Applications :

CHANNEL DEFINATION FORMAT (.cdf) : use a .cdf file to add a site to the user's favorite file folder & subscribe to the channel, checking back periodically for updates.

SMIL : Synchronized Multimedia Integration Language : It is W3C standard at
SMIL applet in Java at

SMIL has become a core part of the Real Networks streaming software and Apple Quicktime.

Wednesday, March 22, 2006

Oracle SQL : I

SELECT *|{[DISTINCT] column|expression|group_function(column) [[AS] alias],....)}
FROM table
[WHERE condition(s)]
[GROUP BY group_by_expression]
[HAVING group_condition]
[ORDER BY {columns,column alias,expr} [ASC|DESC]];

DISTINCT : eliminates duplicate rows.
ASC : NULL values are displayed last. DESC : NULL values are displayed first.


Table columns descriptions:
NUMBER(p,s) :
VARCHAR2(s) : variable length character value of max size s.
DATE : date between 1-Jan-4712BC & 31-Dec-9999AD.
CHAR(s) : fixed length character value of size s.

1. Arithmetic Expressions [BMDAS : revised BODMAS? :) ]:

2. Concatenation operator:
|| : same as concat(string,string)

Eg : select last_name||' :1month salary='|| salary FROM employees;

3. Comparision conditions:
<>, !=, ^=

4. Other Comparison conditions:
LIKE : match a character patten.
% : zero of more characters. eg : LIKE 'S%'
_ : one character. eg : LIKE '_O%'

To search for actual wide card characters use ESCAPE.
eg: WHERE job_id LIKE '%sale\_%' ESCAPE '\';


Logical conditions:

Rules of precedence:

1. Arithmetic operators
2. Concatenation Operators
3. Comparison conditions
6. NOT
7. AND
8. OR

null : unavailable, unassigned, unknown or inapplicable.

Arithmetic expressions with a null component will return null. x divide by a null value returns null and not error.)

Literals : String & date literals are to be enclosed in single inverted commas (' '), number need not.

Tuesday, March 21, 2006

Win XP tweaks

Following is the extract of useful windows XP teaks i found on the net.

1. bootvis.msi : Analyse the boot up sequence and optimise. My PC boot up speeded up from torturous 7 minuts to a more tolerable 3.5 minutes.

2. Utility at is useful.


on Friday 06 January 2006 by Adam author list email the content item print the content item
in article > Tutorials

These Settings will fine tune your systems memory
You need at least 256MB of ram to do this:
Go to Start > Run then type in REGEDIT -and then to the following key:
HKEY_LOCAL_MACHINE\SYSTEM \CurrentControlSet\Control\Session Manager\Memory Management

1.DisablePagingExecutive -Double click it and in the decimal put a 1 - this allows XP to keep data in memory now instead of paging sections of ram to harddrive yeilds faster performance.

2.LargeSystemCache- Double click it and change the decimal to 1 -this allows XP Kernal to Run in memory and improves system performance a lot.

3.IOPageLockLimit - Create a new dword and name it double click it and set the value in hex - 4000 if you have 128MB of ram or set it to 10000 if you have 256MB set it to 40000 if you have more than 512MB of ram -this tweak will speed up your disckcache.


-Unable to delete from Avi files from HD

XP holds files in it's memory even after you have closed the application using them making it impossible to delete them from your harddrive. To fix this:
Start -> Run -> Regedit
Find the HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shel lex\PropertyHandl er\ directory and delete the "DEFAULT" key.

-Tweak The Swap File

For Users with 256 MB RAM or more this tweak will boost their Windows- and Game-Performance.
What it does: It tells Windows not to use any Swap File until there is really no more free RAM left.
Open the System Configuration Utility by typing msconfig.exe in the RUNConservativeSwapfileUsage =1" under the 386enh section.
Restart your Windows and enjoy better Game performance
command. There in your System.ini you have to add "

-Disable Services

XP Pro runs a lot of services by default that are pointless if your not on a corporate network, the following services are ones that I safely disable thereby freeing up memory but check what each one does first to make sure your not using it for something:

Go to Run and type services.msc, right click on each service, properties and choose disable.

Application Layer Gateway Service,
Application Management
Automatic Updates
Background Intelligent Transfer
Distributed Link Tracking Client
Distributed Transaction Coordinater
Error Reporting Service
Fast User Switching Compatibility
IMAPI CD-Burning
Indexing Service
IPSEC Services
Net Logon
Net Meeting
Remote Desktop Sharing
Network DDE
Network DDE DSDM
Portable Media Serial Number
Remote Desktop Help Session Manager
Remote Registry
Secondary Logon
SSDP Discovery Service
Telnet Themes
Uninterruptible Power Supply
Universal Plug and Play Device Host
Upload Manager
Wireless Zero Configuration
WMI Performance Adaptor

-Speed Up The File System

NTFS is a great file system, but its feature-set comes at a slight cost in performance. You can negate this a little with the following tips:

* By default NTFS will automatically update timestamps whenever a directory is traversed. This isn't a necessary feature, and it slows down large volumes.
Disable it by going to Run and type regedit:

HKEY_LOCAL_MACHINE\SYSTEM \CurrentControlSet\Control\FileSystem and set 'DisableNTFSLastAccessUpd ate' to 1.

* NTFS uses disparate master file control tables to store filesystem information about your drives. Over time these core MFT files grow and become fragmented, slowing down all accesses to the drive. By setting aside a little space, MFT's can grow without becoming fragmented.

In the same key where you disabled the last access feature creat a new DWORD value called 'NtfsMftZoneReservation' and set it to 2.

-Disable DLL Caching

Windows Explorer caches DLLs (Dynamic-Link Libraries) in memory for a period of time after the application using them has been closed. This can be an inefficient use of memory.

1. Find the key [HKEY_LOCAL_MACHINE\SOFTWA RE\Microsoft\Windows\Curr entVersion\Explorer].

2. Create a new DWORD sub-key named 'AlwaysUnloadDLL' and set the default value to equal '1' to disable Windows caching the DLL in memory.

3. Restart Windows for the change to take effect.

-Tweak The Prefetch

1. Run "Regedit"
2. Goto [HKEY_LOCAL_MACHINE\SYSTEM \CurrentControlSet\Contro l\Session Manager\Memory Management\PrefetchParame ters\EnablePrefetcher]

3. Set the value to either 0-Disable, 1-App launch prefetch, 2-Boot Prefetch, 3-Both ("3" is recommended).

4. Reboot.

It will decrease the boot time but double and increase the performance of your XP.

-Performance Increase Through My Computer

Easy enough tweak to usually find out about it on your own, but still, some of us still don't find it right away. So here it is:

Start > right-click on My Computer and select Properties.
Click on the "Advanced" tab.
See the "Performance" section? Click "Settings".
Disable the following:

Fade or slide menus into view
Fade or slide ToolTips into view
Fade out menu items after clicking
Show Shadows under menus
Slide open combo boxes
Slide taskbar buttons
Use a background image for each folder type
Use common tasks in folders
There, now Windows will still look nice and perform faster.

-Remove Windows Messenger

Go to Start/Run, and type: "rundll32 setupapi,InstallHinfSection BLC.Remove 128 %SystemRoot%INFmsmsgs.inf"

Do Not Highlight Newly Installed Programs

Tired of that annoying little window that pops up to tell you that new software is installed? If it gets in the way when you?re logging off, turn it off completely. To do this:

Click Start, right-click at the top of the Start menu where your name is displayed, and then click Properties.
In the Taskbar and Start Menu Properties dialog box, on the Start Menu tab, click Customize.
Click the Advanced tab, and then clear the Highlight newly installed programs check box.
Click OK, and then click OK again.

-Customize the Start menu

The Start menu gets more real estate in XP than in previous versions, and it's more customizable. To make the Start menu display only the applications you want, rather than the default determined by Microsoft:

Right-click in an empty section of the Start menu's left column.
Select Properties > Start Menu > Customize. Here you'll find a list of your most frequently used programs. (XP keeps track of what you use and what you don't, then updates this list dynamically).
Don't want your boss to know that Pinball, Solitaire, and Quake all make your list?

Go to the General tab, click Clear List, and set the counter to zero.

- Search Companion Error

When doing a file search, if you get the error A File That Is Required to Run Search Companion Cannot Be Found

Log on as an Administrator
Click Start
Select Run
Enter in the command - %systemroot%\inf
Right-click the Srchasst.inf file
Click Install

-Installing the Backup Program on the Home Version

By default, the NTBACKUP program is not installed on the home version.

You can find it on the CD in the \VALUEADD\MSFT\NTBACKUP directory

Since not all vendors include the actual source code for XP,
you can download a copy

-Changing Drive Letters

If you want to change the letters assigned to your fixed or removable drives:

Right Click on My Computer
Select Manage
Select Disk Management
For a Fixed Disk:

Select it
Right click
Select Change Drive Letter and Path
Click on the Edit button
Enter in the letter you want to use
For a Removable Disk:

In the lower, right hand panel, right click on the Disk or CD ROM #
Select Change Drive Letter and Path
Click on the Edit button
Enter in the letter you want to use

[COLOR=red]- Turn off the Windows Picture and Fax Viewer as the Default Image Viewer

You can also change the file associations for the specific file types you want.

Open the Windows Explorer
Go to Tools / Folder Options / File Types
Scroll down to the extension you want to change
Click on the Change button
Select the program you want to associate with that extension
Click on the OK button

If the Windows Picture and Fax Viewer is set as the default for many of your
graphic file types,
you can remove it so other graphics programs can be used.

Run Regedit
Go to HKEY_CLASSES_ROOT / SystemFileAssociations / image / ShellEx / ContextMenuHandlers
Delete the key ShellImagePreview
Download reg file

-Allowing Network Access with Blank Passwords

Although you can log in locally without a password, by default, WindowsXP Pro does not allow network users to access the computer without a password.
Typically you will receive an Unknown error 31 if this is the case.

To change this setting:

Run gpedit.msc
Go to Computer Configuration / Windows Settings / Security Settings / Local Policies / Security Options
Double click on Accounts: Limit local account use of blank passwords to console login only
Disable this option

-Changing the Default DOS Window Properties

If you want to change the default DOS windows properties like:

Buffer Size
Window / Full Screen
Open up a DOS window
Right click on the Title Bar
Select Defaults
Make any of the changes you like
All subsequent DOS windows will assume these defaults

-Changing the Registered Owner

Start Regedit
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion
From there you can edit the name in the Registered Owner key

-Opening a Command Prompt to a Particular Directory from Explorer

If you want to open a command prompt to a directory that is selected in the

Start Regedit
Go to HKEY_CLASSES_ROOT \ Directory \ shell
Create a new key called Command
Give it the value of the name you want to appear in the Explorer. Something like Open DOS Box
Under this create a new key called command
Give it a value of cmd.exe /k "cd %L"
Now when you are in the Explorer, right click on a folder, select Open DOS Box, and a command prompt will open to the selected directory.
Download reg file

-Adding Time Servers

With WindowsXP, you can double-click on the time in the System Tray and connect to Time Servers on the Internet to synchronize with.
To add to the list of available servers:

Start Regedit
Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\DateTime\Servers
Add new string keys named 2, 3, etc. with a value of the time server you want to use.

-Creating a Boot Floppy

To create a bootable floppy from within WindowsXP:

Insert a floppy into the A: drive
Open the Explorer
Right click on the A: Drive
Select Format
Check Create an MS-DOS startup disk
Click on the Start button
This will create a Millennium boot disk

-Changing the Login Screen Saver

If you want to change the screen saver that runs at the login prompt:

Start Regedit

Go to HK_USERS / .DEFAULT / Control Panel / Desktop
Double click on SCRNSAVE.EXE
Enter in the screen saver you want to use

-Running NetMeeting

To run NetMeeting:

Do a Start / Run
Enter conf
Answer the prompts along the way for name, e-mail etc.

-Set the Online Registration as Being Completed

You can set WindowsXP to assume the online registration has been completed.

Run Regedit
Go to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT CurrentVersion
Create a String Value called RegDone
Give it a value of 1
Download reg file

-Decreasing Boot Time

Microsoft has made available a program to analyze and decrease the time it takes to boot to WindowsXP
The program is called BootVis

Uncompress the file.
For a starting point, run Trace / Next Boot + Driver Delays
This will reboot your computer and provide a benchmark
After the reboot, BootVis will take a minute or two to show graphs of your system startup.
Note how much time it takes for your system to load (click on the red vertical line)
Then run Trace / Optimize System
Re-Run the Next Boot + Drive Delays
Note how much the time has decreased
Mine went from approximately 39 to 30 seconds.

-Re-Enabling System Restore

If you previously disabled system restore through the Group Policy Editor,
the option to start it again does not show in the System Properties.
You can re-enable it again by:

Run the Group Policy Editor (gpedit.msc)
Go to Computer Configuration / Administrative Templates / System / System Restore
Set Turn off System Restore and Turn off Configuration to Disable
Right click on My Computer
Select Manage
Go to Services and Applications / Services
Scroll down to System Restore Service
Set it for Automatic
Click on the Start button to start the service
Close down this window
Go back to the Group Policy Editor and configure both to Not configured
Now when you right click on My Computer, there should be a tab for System Restore and you can configure how much space will be used.

-Hide/Unhide Logon Names

If you want to hide or unhide the names of users that are displayed on the initial logon screen:

Start Regedit
Go to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ Winlogon \ SpecialAccounts \ UserList
Add a DWORD with the name of the user account you want to hide
Make sure it has a value of 0
If there is an existing account, you can unhide it by giving it a value of 1

-Speed up start menu

Start -> Run -> regedit

HKEY_CURRENT_USER\Control Panel\Desktop and then right click on ""MenuShowDelay" and click on "Modify", the figure you have here is in milliseconds. The standard is 400, I have mine set to 50, 0 is instant.
Take your pick

Set your L2 cache

It was on 0 kb after my windows installation.

1. Go to run -> type Regedit

2. Go to _> hkey_local_machine\system\currentcontrolset\contro l\session manager\memory management.

3. At 'secondleveldatacache' set it to
'200' for a Level2 Cache of 512 Kb
For 1 Mb L2 cache fill in '400' ... and so on

(With this freeware you can see how much L2 cache you have

Some of them are from

Source - e107.


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