- MS-DOS (/ˌɛmˌɛsˈdɒs/ em-es-DOSS; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as “DOS” (which is also the generic acronym for disk operating system). MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
- Reverse engineering the Intel 386 processor’s register cell (righto.com)
The groundbreaking Intel 386 processor (1985) was the first 32-bit processor in the x86 line. It has numerous internal registers: general-purpose registers, index registers, segment selectors, and more specialized registers. In this blog post, I look at the silicon die of the 386 and explain how some of these registers are implemented at the transistor level. The registers that I examined are implemented as static RAM, with each bit stored in a common 8-transistor circuit, known as “8T”. Studying this circuit shows the interesting layout techniques that Intel used to squeeze two storage cells together to minimize the space they require.