The x86 architecture continues to demonstrate its remarkable legacy of backwards compatibility, allowing users to run operating systems from the 1990s on contemporary hardware with surprising ease. A recent endeavor by Yeo Kheng Meng showcased this capability by successfully booting Windows 98 SE on a 2020 ThinkPad P12s Gen 1, alongside Windows 11 and Linux, all from a single NVMe drive.
Overcoming Modern Challenges
Building on a prior achievement of running MS-DOS 6.22 from 1994 on a 2020 ThinkPad X13, the transition to Windows 98 SE proved to be a logical next step. The primary hurdles encountered stemmed from the complexities of UEFI and the need for compatible hardware drivers.
Both ThinkPad models share the advantage of supporting UEFI-CSM mode, often referred to as ‘classical BIOS.’ This is particularly significant, as UEFI booting was not even a concept when Windows 98 was originally launched. The challenge then shifted to gathering the necessary hardware drivers to facilitate the installation.
- To address the lack of xHCI (USB 3.0) support in Windows 98, Yeo ingeniously connected a USB 2.0 expansion card through a Thunderbolt dock.
- With this workaround in place, the installation process became straightforward: disabling Secure Boot in the BIOS, enabling UEFI-CSM, activating Thunderbolt BIOS assist mode, and turning off Kernel DMA protection.
Given the often buggy nature of UEFI-CSM implementations, Yeo utilized the CREGFIX DOS driver to enhance stability. Another nostalgic challenge arose as Windows 98, by default, cannot utilize more than 512 MB of RAM. Thankfully, patches from Rudolph Loew provided solutions to this limitation and addressed several other minor issues.
However, the absence of updated drivers from Intel and NVIDIA for Windows 98 means that users must rely on basic VESA support and the SoftGPU driver for graphics acceleration. Disk access is also routed through the BIOS instead of utilizing an NVMe driver, resulting in less-than-optimal performance, though still functional for a Windows 9x environment.
ACPI support presented yet another challenge, as Windows 98 does not recognize it. This can largely be attributed to the convoluted nature of ACPI itself, rather than any shortcomings of the operating system. Yeo managed to navigate this issue by configuring the BIOS to support the S3 power state, restoring functionality to Windows 98.
It is somewhat disheartening that UEFI-CSM is frequently overlooked in newer systems, as this oversight complicates the installation of even Windows 7. This trend has likely contributed to one of the most significant divides within the x86 ecosystem since the introduction of AMD64/x86_64.
