Function, Structure, Operation and File Management
  • MS-DOS filenames must have 1 to 8 characters. There can be no spaces or punctuation in the filename. The file extension can have up to 3 characters, allowing 11 total characters in the filename.

  • Long File Names - Win95 supports extended file names which can contain up to 255 characters. In Win95, each long file name has a duplicate 8.3 file name for backwards compatibility.

  • PROGMAN.EXE - is the program that starts Windows 3.x sessions during the loading process. Located in the C:\WINDOWS (unless directory is specified otherwise in installation) directory.

  • CONTROL.INI - Contains desktop settings and is located in the C:\WINDOWS directory.

  • 386SPART.PAR - Permanent swap file in Windows 3.x.

  • WIN386.SWP - Temporary swap file in Windows 3.x.

    Windows 95 is a true operating system, but Windows 3.x is only a graphical interface to MS-DOS.

    Windows 95 can run either 32 or 16 bit applications.

    Windows 3.x can only run 16 bit applications.

    COMMAND.COM - Acts as a "translator" for processing requests before they are sent directly to the processor.

    The Control Panel in both Windows 3.x and Windows95 only configures system settings.

  • MSDOS.SYS - Only used by MS-DOS, not Windows 95.

  • WIN.COM - Starts Windows 3.x

    Windows 95 uses the fat32 file system.

    MS-DOS uses the fat16 file system.

    Loading order of MS-DOS:

      1) IO.SYS
      2) MSDOS.SYS
      3) CONFIG.SYS
      4) COMMAND.COM

    Minimum files that MS-DOS needs to load:

    • IO.SYS

    BUFFERS= and Smartdrv both have to do with caching in MS-DOS.

    The DEVICE= command in CONFIG.SYS loads device drivers into the memory.

    INTERNAL dos commands are in COMMAND.COM.

    PIF is a Program Information File for DOS programs.

    DLL files are shared executable pieces of code that help reduce the size of applications that use them.

    The Add/Remove Programs applet in Control Panel can be used to create startup disks.

    The F4 key allows you to boot into an old operating system in a system that has Windows 95 as the default OS.

  • SHARE.EXE - allows file locking in MS-DOS.

  • MSD - MS-DOS utility that allows you to view the system's processor type.

    DIR and CHKDSK can both give the total disk space on an MS-DOS system.

    The ROM BIOS is programming that communicates directly with a computer's hardware.

    Giving an application the Execute in Foreground option from the 386 Control Panel applet in Windows 3.x helps to speed up the application.

    SYSTEM.INI - Contains drivers and VXD's for Windows devices in Windows 3.x and Windows 95.


    The [boot] portion of the SYSTEM.INI has the drivers that are loaded at startup.

    Windows 95 detection log files:

    • 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.

    The Windows 95 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.

  • REGEDIT.EXE - Used to modify the Registry.

    The Windows 95 Registry is composed of USER.DAT and SYSTEM.DAT.

    The majority of the configuration settings of Windows 95 are in the Registry.

    A virtual machine is an illusional environment created by the operating system in memory. 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 has three core components:

    • 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.
    All three are .DLL files which reside in the system as both 16-bit and 32-bit applications to maintain backwards compatibility.

    Plug and Play is designed so that no user intervention is required in order to install hardware.

    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.

    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.

    Hard Drive caching in Windows 95 is handeled with VCache.

  • Memory Management
    Conventional Memory 1k-640k Used for DOS applications and TSR's.
    Upper Memory 640k-1024k Used to load MS-DOS device drivers to help increase space available for DOS applications.
    High Memory Area 1024k - 1088k. Reserved for use by single application or utility.
    Extended Memory 1088k - end of memory Was created for DOS applications to be able to access RAM outside of the first 640k.
    Expanded Memory Uses virtual memory Uses bank-switching to page data in and out of memory quickly.

  • MEM.EXE - MS-DOS utility that allows you to view memory usage.

  • MEMMAKER.EXE - Used to optimize memory usage in MS-DOS.

    Windows 3.x must have 2048k minimum to run in 386 Enhanced mode.

    HIMEM.SYS and EMM386.EXE are both memory managers.

  • Installation, Configuration, and Upgrading
    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

    Minimum Hardware Requirements for Windows 3.x:

    • 286 computer (will only run in standard mode on a 286)
    • MS-DOS 5.0 or above previously installed
    • 2mb of disk space for an upgrade from previous windows version; 5mb for a new installation
    • 640k conventional and 1024k extended memory for enhanced mode; 640k conventional and 256k of extended memory for standard mode
    • Pointing device
    • Video card that has a compatable Windows 3.x driver

    Windows 95 Setup Options:

    • Typical- Recommeded setup option for minimum user interaction.
    • Compact- Minimum installation available, for computers with little hard disk space available.
    • Portable- For users with portable computers, includes utilities for remote computing.
    • Custom- Lets user choose which features to include in installation.

    The Express setup of Windows 3.x does not allow you to choose the location of the Windows directory.

    Old system files are not saved when using the Windows 95 Custom setup.

  • SETUP.EXE - File used to install MS-DOS, Windows 3.x, and Windows95.

    Pressing F3 during the install of MS-DOS, Windows 3.x, or Windows 95 will terminate the setup.

    The default directory for MS-DOS installation is C:\DOS.

    Windows 3.x Express setup automatically chooses which applications and utilities will be installed on a system, and automatically creates icons for pre-existing Windows programs.

    • Use the /A option for installing Windows 3.x if you plan to run Windows off of a network. (You must use /N in combination with this)
    • Use the /N option to install Windows 3.x from the network.
    • Use the /I option to have setup ignore the hardware it detects and allows you manually select it.

    Network configuration is part of the Windows 95 installation process, but can be done later after the setup is complete.

  • Diagnosis and Troubleshooting
    General Protection Faults (GPFs) happen when the same memory is allocated to more than one application.

    Safe Mode is a diagnostic mode that loads only the minimum drivers necessary to launch Windows 95.

    The F8 key allows you to choose between the following boot options for Windows 95: Normal, Safe Mode, Safe Mode with network support, Step by Step Confirmation, Command Prompt, and Previous Version of MS-DOS.

    The F5 key allows you to boot directly into the Safe Mode of Windows 95.

    The F5 key bypasses the AUTOEXEC.BAT file and the CONFIG.SYS file in both MS-DOS and Windows 95.

    Pressing the F8 key in MS-DOS allows you to step through config.sys and autoexec.bat line-by-line.

    If COMMAND.COM is missing, you will recieve a "Bad or missing command interpreter" error message.

    CHKDSK and SCANDISK are both hard drive testing programs.

  • DEFRAG.EXE - Used to defragment the hard drive.

    Make sure you document any troubleshooting performed.

  • Networks
    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.

    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.

    TCP/IP is an Internet protocol currently used for most networking situations. Each computer using TCP/IP will contain a unique IP address in a x.x.x.x format (where each x equals a number between 0 and 255) and a subnet mask.

    TCP/IP is the protocol that must be loaded in Windows 95 in order to connect to the Internet.

  • 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.