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Minimum Hardware Requirements for Windows
95
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Intel 386DX, 20MHz processor or higher
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4MB RAM
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VGA Video adapter and display
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20MB free hard disk space
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Windows 95 Setup Options
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Typical- Recommeded setup option for minimum
user interaction.
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Compact- Minimum installation available, for
computers with little hard disk space available.
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Portable- For users with portable computers,
includes utilities for remote computing.
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Custom- Lets user choose which features to
include in installation.
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Detection Log Files
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Windows 95 has several log files generated to detect
and troubleshoot problems.
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SETUPLOG.TXT- Used to log installation of Windows95.
Will note last utility run prior to a system halt.
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DETCRASH.LOG- Used to log hardware detection
during setup. Readable only by setup to determine which module was
running when the system halted.
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DETLOG.TXT- Equivalent of DETCRASH.LOG written
in a readable format.
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NETLOG.TXT- Logs detected network component
information.
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IOS.LOG - Logs error messages from the SCSI
drivers.
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PPPLOG.TXT - Logs PPP and dial-up activity.
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The infamous Windows 95 Registry
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The Registry is designed as a database used by OLE
to store information on OLE servers. It is used by Windows 95 to store
the information typically found in Windows 3.x .INI files and the
reg.dat file. The Registry can be used for troubleshooting and enhancing
perfomance in Windows 95. The registry is a heirarchical tree which
contains information about many things in the computer. The following
is a list of the Registry subtrees and what they contain:
Subtree
|
Information stored within
|
HKEY_CLASSES_ROOT |
Contains information about OLE servers and file associations.
It contains the same information that is typically stored in the
reg.dat in Windows 3.x. |
HKEY_CURRENT_USER |
Contains the preferences of the user who is currently logged
in. Receives stored information from the user's subtree located
in HKEY_USERS. |
HKEY_LOCAL_MACHINE |
Contains hardware information and settings for any device ever
installed in the computer. |
HKEY_USERS |
Contains preferences for every user that has ever logged into
the computer. |
HKEY_CURRENT_CONFIG |
Contains settings for all hardware devices currently installed
in the computer. Does not contain settings for devices included
in HKEY_DYN_DATA. |
HKEY_DYN_DATA |
Contains dynamically stored data on performance monitoring. |
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You can use the program Regedit.exe to modify
the Registry.
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The Registry contains three properties: Name,
Data Type, and Value. The Data Type can be a
binary value (a collection of bits), a string value (a string of readable
characters) and a DWORD value (a binary value limited to 4 bytes).
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Intel Memory Protection Architecture
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The 386 architecture has four priveledge levels designed
to protect data from being damaged. Level 0 is the highest, and level
3 is the lowest. Windows 95 only uses levels 0 and 3. It uses level
0 for 95 core components and level 3 for user applications and non-critical
components.
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Virtual Machines
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A virtual machine is an illusional environment created
by the operating system in memory. Virtual machines run in ring 3
of the Intel architecture. These are designed to allocate resources
to programs that might normally be halted by other programs in memory.
Each MS-DOS application runs in its own virtual machine, as they are
designed to have total and uninterupted access to all system resources.
All other non-MS-DOS based programs run in the System virtual machine.
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Windows 95 Core Components
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Windows 95 has three core components: Kernel, User
and GDI. All three are .DLL files which reside in the system as both
16-bit and 32-bit applications to maintain backwards compatibility.
Kernel - Responsible for basic O/S functionality, managing
virtual memory, task scheduling, and File I/O services.
User - Manages the user interface, including input from devices
and interaction with drivers.
GDI - Responsible for all graphics manipulation.
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Plug and Play
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Plug and Play - designed for hardware installation
to require no intervention from the user.
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A plug and play system needs to consist of the following
to be complete:
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- A plug and play operating system
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- A plug and play BIOS
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- Plug and play hardware
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Legacy Cards - Hardware designed prior to Plug
and Play which, when installed, will not automatically be setup by
the OS and must be setup manually.
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Bus Enumerator - Type of driver based on a
specific bus architecture. Used to build the hardware tree in the
registry.
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Plug and Play Docking
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Docking - The process which a computer uses
to establish connection with a docking station.
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There are three types of docking:
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Hot - Computer can be at full power when it
is docked or undocked
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Warm - Computer can be in sleep mode when it
is docked or undocked
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Cold - Computer can must be turned off before
being docked or undocked
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Disk operations
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IFS (Installable File System) - architecture
which allows multiple file systems to coexist on the same computer.
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VFAT - 32-bit virtualized File Allocation Table
used in Win95.
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VCache - 32-bit protected mode cache driver
which replaces the real-mode SmartDrive.
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Long File Names - Win95 supports extended file
names which can contain up to 255 characters, unlike DOS which was
limited to the 8.3 structure. In Win95, each long file name has a
duplicate 8.3 for backwards compatibility.
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Memory
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Conventional Memory - First 640k of RAM, used
for DOS applications and TSR's.
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Upper Memory - 384k RAM located between 640k
and 1mb. Used to load MS-DOS device drivers to help increase space
available for DOS applications.
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High Memory Area - Region between 1024k and
1088k.
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Extended Memory - Region extending from 1088k
to the end of the memory. Was created for DOS applications to be able
to access RAM outside of the first 640k.
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Expanded Memory - Uses bank-switching to page
data in and out of memory quickly.
Virtual Address Spaces
Each process is alloacted a virtual address space for
the process's threads to use. This virtual space appears to be 4g in
size, with 2g to process for its storage, and 2g for operating system
components.
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0-4M MS-DOS Compatibility Arena
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The lower 4m is reserved for real-mode device drivers,
TSRs and 16-bit applications.
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4M-2G 32-Bit Windows Applications (Private Arena)
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This area is reserved for 32-bit Windows applications,
which receive their own unique address space.
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2G-3G DLLs and Shared Objects (Shared Arena)
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This area is used to share core system components,
shared DLLs, and 16-bit Windows applications.
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3G-4G Reserved System Area
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Ring 0 components are mapped into this area; this
area is not accessible by Ring 3 components.
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Threads and Processes
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Thread - The basic entity to which the operating
system allocates access to the CPU.
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Process - The code, data and resources which
makeup an application. Each process contains at least one thread that
execute's the process code.
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Thread Priorities - Used to determine which
thread will be allowed to run next. Each thread can have a priority
number between 0 and 31 with 31 being the highest priority. The ranges
of 0-31 are for NT compatibility. The priority values are divided
into two sections: 0-15 for variable priority threads, and 16-31 for
fixed priority threads.
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Thread Scheduling - there are three states a thread
can be in:
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Ready - Thread is ready to be executed by the
scheduler.
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Waiting - Thread is waiting for an event to
occur to come into the ready state.
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Running - Thread is running; only one thread
can be running at one time.
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Primary Scheduler - Responsible for making
sure the highest priority thread is running.
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Secondary Scheduler - Makes sure no thread
hogs the CPU.
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Multitasking
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Preemptive multitasking - The O/S divides time
into slices (20ms for Win95) and proportions the evenly between running
applications.
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Cooperative multitasking - Applications are
required to give up control of the CPU and let other applications
take their turn. Some applications tend to hog the CPU using this
method.
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Multithreading - Used by the preemptive multitasking
in Win95 to allow an application to have multiple paths of execution
(threads).
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Video
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VGA fallback - ensures an incompatible video
driver will not prevent you from accessing the system. For this to
work, there must be a line in the [boot] section of the system.ini
reading -- DisplayFallback=0
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The color depth is measured in bpp (bits per pixel).
The following is a chart relative to the realtionship between bpp
and color depth.
Color Depth
|
BPP
|
16 colors |
4 |
256 colors |
8 |
32k colors (16-bit) |
15 |
64k colors (16-bit) |
16 |
16.7 million colors |
24 |
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Printing
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Image Color Matching - Allows applications
to provide closer matches for color between graphics displayed on
the screen and the same graphics when they are printed. Each devices
properties are stored in a profile. These profiles were designed by
InterColor 3.0 (a number of vendors which included Kodak, Microsoft,
Apple, Silicon graphics, etc.).
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Bidirectional printing - Allows two-way communications
between the printer and computer. The printer is able to send status
and diagnostic information to the computer and its operating system.
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What is needed for bidirectional printing:
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- A bidirectional printer
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- An IEEE 1284 compliant printer cable
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- A bidirectional printer port on the computer
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Printer Drivers
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Unidrv.dll - Printer driver which is used to
print to all non-postscript printers.
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Friendly Names - Allows printer to be named
with a "normal" name which is up to 32 characters in length.
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EMF Spooling - Increases performance in the
way the computer spools print jobs to the temporary file and allows
the application to return to a usable state quicker.
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MS-DOS application printing support
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Windows 3.x and DOS-based files have been known to
have printing problems in Windows 95. The problem is that the program
will say that it has spooled the print job to the printer, but the
printer never receives the job. The problem is being caused by the
programs inability to understand the Windows 95 printing system. Windows
95 has included an MS-DOS printing compatibility feature to allow
older programs to print to a virtual LPT port. Windows 95 will map
an LPT port to the desired print queue which the older program recognizes.
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Printer Icons
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Every printer has an icon which refers to how it is
used to print:
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Printer icon with a hand icon - local printer which
is shared
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Printer icon alone - local printer unshared
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Printer icon with cable attached to bottom - network
printer
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Printer icon with diskette - printer which is set
to print to a file
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Point-and-print - the method of using drag
and drop to print a document. For example, you can create a shortcut
to a printer on your desktop. Then, you can take a MS Word document
and drag it to the printer icon. This will then print the document
without the need to start the application.
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Networking
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Universal Naming Convention (UNC) - Universal
network pathname which is integrated into Win95. Named as \\computername\sharename.
The \\computername will be the name given to your computer in the
network properties screen. The \sharename will be the name you give
to a directory when you share it.
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Browse Master - A computer on the network which
is designated to maintain an active list of all computers in the workgroup.
Win95 can be designated as having the Browse Master disabled (cannot
be a browse server), enabled (will be a browse server) or automatic
(will become a browse server if necessary). In a client/server environment,
it is best to keep the Browse Master disabled as it has been known
to cause conflicts with servers acting as the Browse Master.
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Security levels
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Share-level security - Used in Windows 95 to
share resources. A password is needed to access the resource.
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User-level security - Used in Windows NT to share
resources. When you attempt to access a shared resource, the server
will make sure your user account has been authorized to access the
resource. User-level security can be implemented in Windows 95 if
specified in the Network Properties menu under the Access
Control tab.
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Networking with Novell Netware
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Novell Netware typically uses the IPX (AKA NWLink)
protocol for network communications. Novell Netware 4.11 has TCP/IP
capabilties. Frame type describes the format used to encapsulate IPX
packets, and must be the same on connecting systems.
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Novell Netware by default does not support long file
names. To enable long file names on your netware server, enable OS/2
name space (HPFS).
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Client for Netware is needed for connecting to Novell
Netware servers.
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Client for Netware uses NCP (Netware Core Protocol)
as the redirector.
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ODI is Novell's version of NDIS.
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File and Print sharing for Netware is needed when
sharing files to other Netware clients. This requires user-level security
for pass-through authentication to a Netware server.
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NetWare servers advertise their services using the
Service Advertising Protocol (SAP) to make broadcasts over the network.
Routers will maintain a database of available NetWare servers.
NetWare commands
syscon - administers accounting, file server, user and group
information.
filer - configures volume, file, and directory information.
pconsole - manages NetWare print queues.
netadmin - manages NDS services.
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TCP/IP
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TCP/IP is an internet protocol currently used
for most networking situations. Each computer using TCP/IP will contain
a unique address in a x.x.x.x format (where each x equals
a number between 0 and 255) and a subnet mask.
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Subnet mask - A value that is used to distinguish
the network ID portion of the IP address from the host ID.
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Default gateway - A TCP/IP address for the
host which you would send packets to to be sent elsewhere on the network.
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Common TCP/IP problems are caused by incorrect subnet
masks and default gateways.
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Win95 uses three methods to resolve NetBIOS names
to IP addresses:
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- broadcasts - a computer will broadcast the NetBIOS
name it is searching for across the network. The machine with the
mataching NetBIOS name will send a reply to the broadcasting computer
with its IP address.
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- LMHOSTS - a file normally located in the windows
directory which contains a list of frequently used IP address and
hostnames.
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- WINS (Windows Internet Naming Service) - Win95 contacts
an NT Server running these services to dynamically resolve NetBIOS
names to IP addresses.
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DHCP (Dynamic Host Configuration Protocol)
- Win95 contacts an NT Server running this service to automatically
obtain an IP address each time it logs onto the network.
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Server-Based Setup
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Windows 95 can use a server-based setup to be installed
from a server. This will keep most or all of the files on a server,
which your PC will connect to upon each boot.
Machine Directory - directory on server which
stores computer-specific configuration files (system.dat, user.dat,
.ini files, etc.) for a PC. Is mandatory to use when the PC does not
have a hard drive. Machine directory can be shared for multiple PCs
with the same configuration.
Shared installation files can be stored in one of
three places:
Startup disk - Boot disk which contains mini-registry which
will give it enough information to boot to the network/shared server.
Machine Directory
Shared installation directory - Contains all Win95 filesand
is flagged as read-only.
You can use Batch.exe (located in the admin\nettools\netsetup
directory on the CDROM) to create batch setup scripts for use after
the installation.
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Advanced Administration
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User Profiles - user preference settings which
are stored locally or on the server, which are reloaded to the system
everytime the user logs in. The settings can be specified to contain
user preferences for the Start Menu, Network Neighborhood,
and the desktop settings. User Profiles can be enabled via the Passwords
Properties menu in the Control Panel.
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Policies - settings which are controlled by
the administrator to control what the user is able to do on their
computer. To use policies, you must have User Profiles enabled. Changes
are made to Policies by using the System Policy Editor (Poledit.exe)
which is located on the Win95 CD. Policies can be setup for individuals,
groups, and also computers. Policies can be stored locally or on the
server. The default policy file is config.pol. To use this
across the network, the file must be placed in the NETLOGON share
of the Primary Domain Controller on a Windows NT network.
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Net Watcher - program which enables the administrator
to remotely view a PC and view the active connections, shares and
open files. Is available when the net watcher service installed in
Network Properties. Does not require user-level security.
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Remote Registry Editor - enables abililty to
remotely edit the registry within regedit.exe. Is only available
if the PC has user-level security enabled, and the remote registry
service installed in Network Properties.
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Remote Administration - administration tool
which enables the administrator to gain access to a remote PC's file
system. To use this, you must have Remote Administration enabled in
the Passwords Properties menu in the Control Panel under
the Remote Administration tab. To gain access to this utility,
enter Network Neighboorhood, right-click on the computer you
would like to administer, and click on Properties. In the next
window, click the Administer button.
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