Windows 95B (OSR2)

Overview

Windows 95B, also known as OSR2 (OEM Service Release 2), released in 1996, is a major update to Windows 95 that introduced FAT32 support, improved disk performance, better hardware support, and increased system stability. Unlike Windows 95A, OSR2 was never sold at retail and was available only through OEM preinstalled systems. It remains one of the most important updates in the Windows 9x line.

Release Information

  • Release year: 1996
  • Type: Consumer desktop operating system (OEM‑only)
  • Platform: 16/32‑bit hybrid (Windows 4.00.1111)
  • Last update: OSR2.1 (USB Supplement), OSR2.5 (IE4 + USB)
  • Predecessor: Windows 95A
  • Successor: Windows 95C (OSR2.5)

Build and Distribution

  • Distributed only with new OEM PCs.
  • Included FAT32 support for large drives.
  • Improved disk performance and reliability.
  • Did not include Internet Explorer by default.
  • Designed for home and small‑office PCs.

System Requirements

Minimum Hardware

  • CPU: 386DX or higher
  • RAM: 4 MB minimum
  • Storage: 50–55 MB hard drive space
  • Graphics: VGA (640×480)
  • Input: Keyboard and mouse

Recommended Hardware (1996–1998)

  • CPU: 486DX4 or Pentium
  • RAM: 8–16 MB
  • Storage: 500 MB–2 GB hard drive
  • Graphics: SVGA with 1–2 MB VRAM

Supported CPU Architectures

  • x86: 386, 486, Pentium

Supported Components

Graphics Cards

  • VGA and SVGA adapters
  • S3 Trio/Virge, Cirrus Logic, Trident, ATI Mach64
  • VESA Local Bus and PCI graphics cards

Sound

Windows 95B supported Sound Blaster‑compatible cards, Windows Sound System devices, and early PCI audio hardware. Multimedia support was improved over earlier Windows 95 releases.

Input Devices

  • Serial and PS/2 mice
  • Standard keyboards
  • Gameport joysticks

Storage

  • IDE hard drives
  • SCSI controllers (with drivers)
  • 3.5-inch floppy drives
  • CD‑ROM drives

File System Support

Windows 95B introduced FAT32, a major improvement over FAT16, allowing support for large partitions and more efficient disk usage.

Supported File Systems

  • FAT12: Floppy disks
  • FAT16: Legacy hard drive partitions
  • FAT32: New file system supporting large drives

Limits

  • FAT16 limited to 2 GB partitions
  • FAT32 supports partitions up to 2 TB
  • No NTFS support

Networking

Windows 95B included improved networking over earlier versions, supporting dial‑up networking, TCP/IP, and peer‑to‑peer file sharing.

Built‑In Networking Features

  • Dial‑Up Networking
  • Network Neighborhood
  • Basic file and printer sharing

Supported Protocols

  • TCP/IP
  • NetBEUI
  • IPX/SPX

Supported Network Cards

  • NE2000 compatible cards
  • 3Com EtherLink III
  • Intel EtherExpress
  • Various ISA and PCI NICs

Driver Information

Driver Sources (1996–1998)

  • OEM installation media
  • Hardware vendor driver disks
  • Windows 95 driver library

Driver Notes

  • FAT32 support required OSR2 or later.
  • USB support not included until OSR2.1/OSR2.5.
  • Some PCI devices required updated OEM drivers.

Updates & Patches

Windows 95B was followed by OSR2.1 (adding USB supplement) and OSR2.5 (adding IE4 and USB).

Related Versions

  • Windows 95A: FAT16‑only version
  • Windows 95B (OSR2): Introduced FAT32
  • Windows 95C (OSR2.5): Added IE4 and USB supplement

Installation Notes

Installation Media

  • OEM‑only CD‑ROM
  • Preinstalled on new PCs

Typical Installation Steps (Historical)

  1. Boot from floppy or DOS.
  2. Run SETUP.EXE from OEM CD.
  3. Choose installation options.
  4. Copy system files and reboot.
  5. Install drivers for graphics, sound, and network cards.

Virtual Machine Notes

Windows 95B runs reliably in emulators and virtual machines with appropriate settings.

  • PCem
  • 86Box
  • VirtualBox
  • VMware

Known Issues & Fixes

Common Issues

  • USB support requires OSR2.1 or OSR2.5
  • Some PCI devices require OEM drivers
  • Limited memory management compared to later Windows versions

Stability Notes

  • More stable than Windows 95A
  • FAT32 improves disk reliability and performance

End of Support

  • Windows 95B reached end of support in December 2001. It remains historically important as the first Windows version to introduce FAT32.

Retro PC Tips

Best Hardware to Run Windows 95B

  • Pentium or Pentium MMX system
  • 16–32 MB RAM
  • SVGA graphics card
  • Sound Blaster‑compatible audio

Keeping It Stable

  • Use FAT32 partitions for best performance.
  • Install OEM drivers for graphics and sound.
  • Use OSR2.1/2.5 if USB support is needed.

Finding Software and Drivers Today

Software and drivers for Windows 95B are available on archival and retro‑computing websites, as well as communities dedicated to classic Windows systems.

Running on Modern Hardware

  • Best run inside emulators such as PCem or 86Box.
  • Direct installation on modern PCs is not feasible due to hardware incompatibilities.