Z-DOS is a discontinuedOEM version ofMicrosoft'sMS-DOS specifically adapted to run on the hardware of theZenith Z-100 personal computer.^{[citation needed]}

Z-DOS isZenith Data Systems's name for a version ofMicrosoft'sMS-DOS operating system designed for theZenith Z-100 computer.^[1] The Z-100 uses a8086-family microprocessor, (theIntel 8088), but otherwise has a completely different internal architecture from theIBM PC.

Microsoft's MS-DOS was not specifically designed to any specific hardware platform, but can be tailored to run on most any system as long as it uses a8086-compatible microprocessor, a situation similar toCP/M, which typically uses a8080-compatible (8080,8085 andZ80 among others) microprocessor. In order to achieve this, MS-DOS, like CP/M, relies on a platform-specific (DOS-)BIOS, which is written for the target machine, so that the hardware-independent DOS kernel can run on it. Beside IBM's OEM version of MS-DOS released asPC DOS there aredozens of other OEM versions of MS-DOS designed for a specific non-IBM-compatible OEM hardware—among them Zenith's Z-DOS. When almost 100% IBM-compatibleclones became the norm, "MS-DOS" became the generic version which could run on most of them. Later such generic versions of MS-DOS cannot run on older non-IBM-compatible machines like the Z-100.

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