Archive for the ‘System Basics’ Category

User logon problems are sometimes hard to troubleshoot. Have you checked the Application log on the machine in question? There might be (most likely) some errors in there from source Userenv (ID’s 1053, 1054).
Turning on Userenv debug logging will also help in troubleshooting user logon problems. You can do this by adding a Registry key:

– Key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
– Value: UserEnvDebugLevel
– Value Type: REG_DWORD
– Value Data: 10002 (Hex)

The log will be located in: %systemroot%\debug\usermode\userenv.log.

In the log you will exactly see what happens during logon at what time. If you see a large difference between times you’ll know what part of the logon process is causing the long delay.

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The core function of DHCP is to assign addresses. DHCP functions at the Application Layer of the Open System Interconnection (OSI) reference model, as defined by the International Organization for Standardization (ISO) and the Telecommunication Standards Section of the International Telecommunications Union (ITU-T).

The OSI model is used for reference and teaching purposes; it divides computer networking functions into seven layers. From top to bottom, the seven layers are application, presentation,

session, transport, network, data-link, and physical

 

In brief, DHCP provides four key benefits to those managing and maintaining a TCP/IP network:

 

  • Centralized administration of IP configuration—DHCP IP configuration information can be stored in a single location and enables the administrator to centrally manage all IP configuration information. A DHCP server tracks all leased and reserved IP addresses and lists them in the DHCP console. You can use the DHCP console to determine the IP addresses of all DHCP-enabled devices on your network. Without DHCP, not only would you need to manually assign addresses, you would also need to devise a method of tracking and updating them.
  • Dynamic host configuration—DHCP automates the host configuration process for key configuration parameters. This eliminates the need to manually configure individual hosts when TCP/IP is first deployed or when IP infrastructure changes are required.
  • Seamless IP host configuration—the use of DHCP ensures that DHCP clients get accurate and timely IP configuration parameters, such as the IP address, subnet mask, default gateway, IP address of the DNS server, and so on, without user intervention. Because the configuration is automatic, troubleshooting of misconfigurations, such as mistyped numbers, is largely eliminated.
  • Flexibility and scalability—Using DHCP gives the administrator increased flexibility, allowing the administrator to more easily change IP configurations when the infrastructure changes. DHCP also scales from small to large networks. DHCP can service networks with ten clients as well as networks with thousands of clients. For very small, isolated networks, Automatic Private IP Addressing (APIPA) can be used.

Hubs and switches are similar in many ways. Both contain connection ports into which twisted-pair RJ-45 connectors (similar to phone RJ-11 jacks) plug. They can be administered remotely. Either can be used to create a LAN, and they funnel messages to the network backbones.

 

There are salient differences between hubs and switches, however:

 

  • Shared or dedicated bandwidth —The main distinction is how they operate. Hosts in a hub-based network share the full bandwidth, but a switch is capable of creating independent full-speed connections for any two devices on the LAN that must communicate. Each connection operates at the full switch bandwidth.
  • How they handle signals —A hub acts like a repeater. It takes an incoming frame and retransmits it to all other attached hosts. Each hub port has a single host connected to it. Hubs are dumb devices and cannot learn. Switches examine incoming frames and immediately transmit them to one or more other ports. This process is very fast. Each switch port can have a single host or a LAN segment connected to it. Switches learn media access control (MAC) addresses and build a contentaddressable memory (CAM) table.
  •  Cost —Switches are more expensive than hubs for the same number of ports because they have more powerful hardware and software capabilities. Switches have more memory, a CPU, and a complete suite of software tools to manage them. Hubs have a trimmed-down version of the firmware code.

 

Like switches, bridges are also layer 2 devices. They learn MAC addresses, filter and forward frames, and can be used to segment LANs. However, they usually have 16 or fewer ports. Much of the functionality of bridges has been moved to routers.

 

Just as routers have replaced bridges at layer 3, switches (as their cost continues to fall) may eventually replace hubs at layer 2, but that has not happened yet. Hubs, it must be pointed out, have become smarter, less expensive, and easier to set up and manage. As more and more LANs are being set up, network managers continue to deploy hubs as an easy and inexpensive way to connect printers, low-traffic servers, PCs, and management consoles. The number of installed hubs is increasing mainly because of cost and simplicity.

Automatic Private IP Addressing

 

Automatic Private IP Addressing (APIPA) is a feature introduced with Windows 2000; it is also included in Windows XP and Windows Server 2003.

 

APIPA allows a computer that is configured to obtain an automatic IP address to assign itself an address from a private range should no DHCP server be available. APIPA assigns addresses in the range 169.254.0.1 through 169.254.255.255—a range reserved by Microsoft for just this purpose.

 

APIPA is really designed for small networks that don’t use a DHCP server. APIPA allows computers running Windows 2000, Windows Server 2003, or Windows XP to plug into a network and recognize one another with little configuration necessary. If your network uses a DHCP server and you see that a client has been assigned an address in the APIPA range, it means the client could not locate a DHCP server.

 

Routing is the process of moving information along a path from a source to a destination.

On a TCP/IP network, the source and destination are called hosts and the information is broken apart into small packets that are transmitted between these hosts. The IP handles the routing of all these packets for the network.

 

Remember that a protocol such as TCP or UDP hands down a packet of data to the IP protocol for transmission to a remote host. IP must determine where the packet goes.

First, it compares the network ID of the local host with the network ID of the destination host identified in the packet. If the two network IDs match, the two hosts are on the same network segment and the packet can be sent directly to the destination host.

 

If IP determines that the network IDs of the local host and the remote host do not match, that means that the two hosts are on different network segments and the packet cannot be sent directly. Instead, IP must send the packet to a gateway, which is a router connecting one network segment to another. When this gateway receives the packet, its IP protocol goes through the process of comparing network IDs to determine the best place to send the packet. If the destination host is on one of the network segments to which the gateway is directly connected, the gateway can forward the packet straight to the destination host. Otherwise, the gateway forwards the packet on to another gateway, and then perhaps another, until the packet finally reaches its destination. Each time a packet crosses a gateway that is referred to as a hop. For example, if a packet must cross three routers to reach its destination that is considered three hops.

 

Usually, the source host is configured with the IP address of a default gateway, a router to which all packets are sent if the destination host is not found on the same network segment. Routers (and all devices with IP installed, for that matter) are able to consult routing tables that are stored in the router’s memory. A routing table holds information on preferred routes for various network IDs. This way, the router can determine the best gateway to which to send a packet based on the network ID of the packet’s destination host. There are two ways in which a router can build its routing table:

 

Static A static router has a routing table that is constructed and updated manually.

In other words, someone must actually access the routing table to create

routes the router can use.

 

Dynamic A dynamic router builds and updates its own routing table as it finds

appropriate routes. When it finds shorter routes, it favors those over longer routes.

Most important, dynamic routers can also share their information with other

routers on the network. Almost all the routers in use today are dynamic routers—

manual routers are just too much work. Dynamic routers use one of two common

routing protocols: Routing Information Protocol (RIP) and Open Shortest Path First

(OSPF).

 

To search Particular set of File Types in a large set of Folders or in a drive, Instead of Windows Search which take long time usually, You can Run a Command which gives you the Log File with the Details of the File name, Location, Drive, space consumed.

To Proceed to Search the files:

1. Open Command Prompt

2. Get to Root Directory (i.e The Drive name in which you want to search)

3. Run the Command “dir /b /n /s *.wma,*.mp3,*.mp4,*.avi,*.mpg,*.mov,*.jpg,*.bmp >C:\ drivespace.txt”

 

You can search any kind of file by editing the above command, I have shown the command to search the Media and Photo files.

The Part (>c:\drivespace.txt) : here you can mention the file name and the path to save the file after execution.

 

Ip Address is a unique address assigned to each computer on a network in order to identify and communicate with each other utilizing the Internet Protocol standard (IP)

Basic Format

A IP address consists of 4 parts (known as Octet), each having three digit ranging from 0 -255 separated by a decimal point.

Example of Valid IP:

10.31.11.25

10.31.11.* (* means all numbers ranging from 0-255 in last octet)

10.31.*.* (* means all numbers ranging from 0-255 in 3rd and 4th octet)

10.31.11.25-155 (25-155 means all number ranging from 25 to 155).

CHKDSK —  Creates and displays a status report for a hard disk and can correct errors on the disk if required. Used without any parameters, CHKDSK simply displays the status of the disk in the current drive. Used with parameters. CHKDSK can locate bad sectors, repair the disk and recover readable information.

To see a status report of the disk, at a command prompt, type, chkdsk and press ENTER. If errors are found, any error message will appear.

To repair errors with the disk, at the command prompt, type chkdsk /f/r and press ENTER. The parameter /f fixes errors on the disk, /r locates bad sectors and recovers readable information. If  you receive a message that chkdsk cannot run because the volume is in use by another process, this probably means that you are trying to fix errors  on the disk that you are currently using. You cannot do that but the computer can repair errors at startup, and you should schedule an autostart in the bootup.

There are several advanced Command Line tools, created and intended  for Network Administrators and advanced users, If interested, try with this command line prompts;

> Bootcfg — Use this command to configure, query or change the boot.ini file settings. Be careful about making changes here !!

>Gpresult — Use this command to test group policy and obtain general information about the operating system, the user and the computer including the build number and the service pack details, user name, domain name, profile type, security privileges, disk quota information and the last time the policy was applied.

>Recover — Use this command to recover readable information from a bad or defective disk.

> Schtasks — Use this command to schedule programs to run at a specific time or at specified intervals.

To see a complete list of available commands for Windows XP including the latest editions, check the Command Line Reference.

Computer Acronyms

Posted: June 19, 2010 in System Basics, System Information
Tags:

ADSL – Asymmetric Digital Subscriber Line

AGP – Accelerated Graphics Port

ALI – Acer Labs, Incorporated

ALU – Arithmetic Logic Unit

AMD – Advanced Micro Devices

APC – American Power Conversion

ASCII – American Standard Code for Information Interchange

ASIC – Application Specific Integrated Circuit

ASPI – Advanced SCSI Programming Interface

AT – Advanced Technology

ATI – ATI Technologies Inc.

ATX – Advanced Technology Extended

— B —

BFG – BFG Technologies

BIOS – Basic Input Output System

BNC – Barrel Nut Connector

— C —

CAS – Column Address Signal

CD – Compact Disk

CDR – Compact Disk Recorder

CDRW – Compact Disk Re-Writer

CD-ROM – Compact Disk – Read Only Memory

CFM – Cubic Feet per Minute (ft�/min)

CMOS – Complementary Metal Oxide Semiconductor

CPU – Central Processing Unit

CTX – CTX Technology Corporation (Commited to Excellence)

— D —

DDR – Double Data Rate

DDR-SDRAM – Double Data Rate – Synchronous Dynamic Random Access Memory

DFI – DFI Inc. (Design for Innovation)

DIMM – Dual Inline Memory Module

DRAM – Dynamic Random Access Memory

DPI – Dots Per Inch

DSL – See ASDL

DVD – Digital Versatile Disc

DVD-RAM – Digital Versatile Disk – Random Access Memory

— E —

ECC – Error Correction Code

ECS – Elitegroup Computer Systems

EDO – Extended Data Out

EEPROM – Electrically Erasable Programmable Read-Only Memory

EPROM – Erasable Programmable Read-Only Memory

EVGA – EVGA Corporation

— F —

FC-PGA – Flip Chip Pin Grid Array

FDC – Floppy Disk Controller

FDD – Floppy Disk Drive

FPS – Frame Per Second

FPU – Floating Point Unit

FSAA – Full Screen Anti-Aliasing

FS – For Sale

FSB – Front Side Bus

— G —

GB – Gigabytes

GBps – Gigabytes per second or Gigabits per second

GDI – Graphical Device Interface

GHz – GigaHertz

— H —

HDD – Hard Disk Drive

HIS – Hightech Information System Limited

HP – Hewlett-Packard Development Company

HSF – Heatsink-Fan

— I —

IBM – International Business Machines Corporation

IC – Integrated Circuit

IDE – Integrated Drive Electronics

IFS- Item for Sale

IRQ – Interrupt Request

ISA – Industry Standard Architecture

ISO – International Standards Organization

— J —

JBL – JBL (Jame B. Lansing) Speakers

JVC – JVC Company of America

– K —

Kbps – Kilobits Per Second

KBps – KiloBytes per second

— L —

LG – LG Electronics

LAN – Local Are Network

LCD – Liquid Crystal Display

LDT – Lightning Data Transport

LED – Light Emitting Diode

— M —

MAC – Media Access Control

MB � MotherBoard or Megabyte

MBps – Megabytes Per Second

Mbps – Megabits Per Second or Megabits Per Second

MHz – MegaHertz

MIPS – Million Instructions Per Second

MMX – Multi-Media Extensions

MSI – Micro Star International

— N —

NAS – Network Attached Storage

NAT – Network Address Translation

NEC – NEC Corporation

NIC – Network Interface Card

— O —

OC – Overclock (Over Clock)

OCZ – OCZ Technology

OEM – Original Equipment Manufacturer

— P —

PC – Personal Computer

PCB – Printed Circuit Board

PCI – Peripheral Component Interconnect

PDA – Personal Digital Assistant

PCMCIA – Peripheral Component Microchannel Interconnect Architecture

PGA – Professional Graphics Array

PLD – Programmable Logic Device

PM – Private Message / Private Messaging

PnP – Plug ‘n Play

PNY – PNY Technology

POST – Power On Self Test

PPPoA – Point-to-Point Protocol over ATM

PPPoE – Point-to-Point Protocol over Ethernet

PQI – PQI Corporation

PSU – Power Supply Unit

— R —

RAID – Redundant Array of Inexpensive Disks

RAM – Random Access Memory

RAMDAC – Random Access Memory Digital Analog Convertor

RDRAM – Rambus Dynamic Random Access Memory

ROM – Read Only Memory

RPM – Revolutions Per Minute

— S —

SASID – Self-scanned Amorphous Silicon Integrated Display

SCA – SCSI Configured Automatically

SCSI – Small Computer System Interface

SDRAM – Synchronous Dynamic Random Access Memory

SECC – Single Edge Contact Connector

SODIMM – Small Outline Dual Inline Memory Module

SPARC – Scalable Processor ArChitecture

SOHO – Small Office Home Office

SRAM – Static Random Access Memory

SSE – Streaming SIMD Extensions

SVGA – Super Video Graphics Array

S/PDIF – Sony/Philips Digital Interface

— T —

TB – Terabytes

TBps – Terabytes per second

Tbps – Terabits per second

TDK – TDK Electronics

TEC – Thermoelectric Cooler

TPC – TipidPC

TWAIN – Technology Without An Important Name

— U —

UART – Universal Asynchronous Receiver/Transmitter

USB – Universal Serial Bus

UTP – Unshieled Twisted Pair

— V —

VCD – Video CD

VPN – Virtual Private Network

— W —

WAN – Wide Area Network

WTB – Want to Buy

WYSIWYG – What You See Is What You Get

— X —

XGA – Extended Graphics Array

XFX – XFX Graphics, a Division of Pine

XMS – Extended Memory Specification

XT – Extended Technology