| 70-063 Minimum Hardware Requirements for Windows 95
Intel 386DX, 20MHz processor or higher
4MB RAM
VGA Video adapter and display
Mouse or equivalent pointing device
20MB free hard disk space
Windows 95 Setup Options
Typical- Recommended setup option for minimum user interaction.
Compact- Minimum installation available, for computers with little
hard disk space available.
Portable- For users with portable computer’s, includes utilities
for remote computing.
Custom- Lets user choose which features to include in installation.
Detection Log Files
Windows 95 has several log files generated to detect and troubleshoot
problems:
SETUPLOG.TXT- Used to log installation of Windows95. Will note
last utility run prior to a system halt.
DETCRASH.LOG- Used to log hardware detection during setup. Readable
only by setup to determine which module was running when the system
halted.
DETLOG.TXT- Equivalent of DETCRASH.LOG written in a readable format.
NETLOG.TXT- Logs detected network component information.
IOS.LOG - Logs error messages from the SCSI drivers.
PPPLOG.TXT - Logs PPP and dial-up activity.
The infamous Windows 95 Registry
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 performance
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.
You can use the program Regedit.exe to modify the Registry.
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).
Intel Memory Protection Architecture
The 386 architecture has four privelege 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.
Virtual Machines
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.
Windows 95 Core Components
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.
Plug and Play
Plug and Play - designed for hardware installation to require no
intervention from the user. A plug and play system needs to consist
of the following to be complete:
A plug and play operating system
A plug and play BIOS
Plug and play hardware
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.
Bus Enumerator - Type of driver based on a specific bus architecture.
Used to build the hardware tree in the registry.
Plug and Play Docking
Docking - The process which a computer uses to establish connection
with a docking station. There are three types of docking:
Hot - Computer can be at full power when it is docked or undocked
Warm - Computer can be in sleep mode when it is docked or undocked
Cold - Computer can must be turned off before being docked or undocked
Disk operations
IFS (Installable File System) - architecture which allows multiple
file systems to coexist on the same computer.
VFAT - 32-bit virtualized File Allocation Table used in Win95.
VCache - 32-bit protected mode cache driver which replaces the
real-mode SmartDrive.
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.
Memory
Conventional Memory - First 640k of RAM, used for DOS applications
and TSR's.
Upper Memory - 384k RAM located between 640k and 1mb. Used to load
MS-DOS device drivers to help increase space available for DOS applications.
High Memory Area - Region between 1mb and 1088k.
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.
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.
0-4M MS-DOS Compatibility Arena
The lower 4m is reserved for real-mode device drivers, TSRs and
16-bit applications.
4M-2G 32-Bit Windows Applications (Private Arena)
This area is reserved for 32-bit Windows applications, which receive
their own unique address space.
2G-3G DLLs and Shared Objects (Shared Arena)
This area is used to share core system components, shared DLLs,
and 16-bit Windows applications.
3G-4G Reserved System Area
Ring 0 components are mapped into this area; this area is not accessible
by Ring 3 components.
Threads and Processes
Thread - The basic entity to which the operating system allocates
access to the CPU.
Process - The code, data and resources which makeup an application.
Each process contains at least one thread that execute's the process
code.
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.
Thread Scheduling - there are three states a thread can be in:
Ready - Thread is ready to be executed by the scheduler.
Waiting - Thread is waiting for an event to occur to come into the
ready state.
Running - Thread is running; only one thread can be running at one
time.
Primary Scheduler - Responsible for making sure the highest priority
thread is running.
Secondary Scheduler - Makes sure no thread hogs the CPU.
Multitasking
Preemptive multitasking - The O/S divides time into slices (20ms
for Win95) and proportions the evenly between runnin applications.
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.
Multithreading - Used by the preemptive multitasking in Win95 to
allow an application to have multiple paths of execution (threads).
Video
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
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 (Bits per Pixel)
16 colors 4
256 colors 8
32k colors (16-bit) 15
64k colors (16-bit) 16
16.7 million colors 24
Printing
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.).
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.
What is needed for bidirectional printing:
A bidirectional printer
An IEEE 1284 compliant printer cable
A bidirectional printer port on the computer
Printer Drivers
Unidrv.dll - Printer driver which is used to print to all non-postscript
printers.
Friendly Names - Allows printer to be named with a "normal"
name which is up to 32 characters in length.
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.
MS-DOS application printing support
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.
Printer Icons
Every printer has an icon which refers to how it is used to print:
Printer icon with a hand icon - local printer which is shared
Printer icon alone - local printer unshared
Printer icon with cable attached to bottom - network printer
Printer icon with diskette - printer which is set to print to a
file
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.
Networking
See the Networking Essentials page to study the OSI model. The
OSI model is relavant to networking with Win95.
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.
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.
Security levels
Share-level security - Used in Windows 95 to share resources. A
password is needed to access the resource.
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.
Networking with Novell Netware
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.
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).
Client for Netware is needed for connecting to Novell Netware servers.
Client for Netware uses NCP (Netware Core Protocol) as the redirector.
ODI is Novell's version of NDIS.
File and Print sharing for Netware is needed when sharing files
to other Netware clients. This requires user-level securit for pass-through
authentication to a Netware server.
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.
TCP/IP
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.
Subnet mask - A value that is used to distinguish the network ID
portion of the IP address from the host ID.
Default gateway - A TCP/IP address for the host which you would
send packets to to be sent elsewhere on the network.
Common TCP/IP problems are caused by incorrect subnet masks and
default gateways.
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.
Name Resolving
Win95 uses three methods to resolve NetBIOS names to IP addresses:
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.
LMHOSTS - a file normally located in the windows directory which
contains a list of frequently used IP address and hostnames.
WINS (Windows Internet Naming Service) - Win95 contacts an NT Server
running these services to dynamically resolve NetBIOS names to IP
addresses.
Server-Based Setup
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.
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.
Advanced Administration
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.
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.
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.
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.
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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