Os8088: A Mac-like OS for IBM PCs
The 1984 Macintosh desktop experience comes alive on IBM XT, 286, and 386.
1Key features of Os8088
Os8088 is an operating system written in real-mode assembly for Intel 8086 processors. Bootable from a floppy disk, it mimics the features of the 1984 Macintosh. It offers overlapping windows, pull-down menus, serial mouse support, and loadable programs. Additionally, it includes pre-emptive multitasking, a feature even the original Macintosh lacked.
2Boot process and technical details
Os8088 boots from the first sector of a floppy disk and loads into a graphical desktop. There is no DOS underneath it, and no command line exists anywhere in the system. The 512-byte boot sector loads a 40KB kernel. The kernel determines the machine's display adapter, switches it to graphics mode, borrows the video card's 8x8 character set, and creates a menu bar.
3User interface and experience
Os8088's user interface resembles the 1984 Macintosh. Windows can be dragged by the title bar, menus can be pulled down and dragged through. Each window has close and minimize boxes. Icons represent each floppy drive, and a dock at the bottom shows running programs. Programs load from a second floppy disk and can run simultaneously.
4Hardware requirements and project details
Os8088 runs on Intel 8086 or 8088 processors with 256KB of RAM. These processors were used in the original IBM PC and PC/XT. The project is a hobby effort and is complete enough to be usable. The source code consists of 66,183 lines of NASM assembly, readable in an afternoon.
5Emulator and real hardware tests
All features of Os8088 were tested in an emulator. In August 2026, disk images were written to actual floppy disks and booted on three period machines: a 1981 IBM 5150, a Toshiba T1100 Plus, and a 286. The results were photographed and documented.
6Historical context and similar projects
In February 1985, Digital Research released GEM 1.0 for the IBM PC. This system offered a Macintosh-style desktop with overlapping windows and icons. Apple sued over this system, and in 1986, GEM Desktop 2.0 removed overlapping windows and desktop icons. Os8088 is a project that revives this idea.
7Technical innovations and differences
Os8088 includes pre-emptive multitasking, a feature not offered by GEM or the Macintosh of the period. The project aims to rebuild this idea on the same class of machine forty years later.
8Demo and download options
The browser demo of Os8088 boots the actual floppy image in an emulated PC. If you prefer to run it yourself, the download page offers 360K images for period hardware and 86Box, and 1.44MB images for QEMU.
Original article: Hacker News — Os8088: IBM PC'ler için Mac benzeri işletim sistemi