The Amstrad/Schneider PC-1512 was an IBM PC-Compatible computer introduced in 1986. The computer had one or two 360kB 5.25" Floppy Disk Drives and a 10 or 20MByte optional hard drive. The Floppy disks could be upgraded to 1.2MByte capacity ones.

Amstrad had licenses for MS-DOS 3.2 and Digital Research DOS Plus. DR-DOS was compatible with MS-DOS, but also had some CP/M features, and was able to read CP/M disks. Amstrad also licensed the GEM Graphical UI windowing system, which was adapted to run on the customized CGA hardware on the PC-1512.

The PC-1512 sold very well in Europe due to it's price-point of £499, which made it one of the cheapest IBM-compatibles available at the time. The design was compact, and the system ran much more silently than some of the other computers on the market. A big difference was that Amstrad had chosen to put the power supply for the computer inside the monitor, which made swapping the monitor for another one a no-go, since the computer needed the power.

The PC-1512 sold well to both home-users and businesses. Even though the computer was marketed to the home-user, the cheap price-point and the features made it a suitable machine to run office software for businesses.

The computer shiped with 512kB of RAM which could be upgraded to 640kByte with 16 4164-120 DRAM chips and changing a jumper on the motherboard. The video was compatible with the CGA standard, but the hardware also had an extention that allowed all 16 colors to be used in the 640x200 graphics mode. The mouse that was provided with the PC1512 was an Amstrad mouse which was incompatible with many games that expected a serial mouse. Amstrad also had chosen to support Atari-compatible joysticks, the keyboard had a digital joystick port that the joysticks could be connected to. The joystick movements and buttons were mapped to keyboard codes, which allowed many games to use the joysticks, even if the game was meant for keyboard control only.

MS-DOS (Microsoft Disk Operating System) originated in 1981 when Microsoft acquired QDOS (Quick and Dirty Operating System) from Seattle Computer Products and adapted it for IBM’s upcoming 8088-based personal computer. Initially branded as IBM PC-DOS 1.0 for IBM, and MS-DOS for other vendors, it provided a single-user, single-tasking environment that was heavily inspired by CP/M. The system was structured around a kernel (IBMBIO.COM and IBMDOS.COM in PC-DOS, IO.SYS and MSDOS.SYS in MS-DOS) that interfaced with hardware and implemented system services, plus a command interpreter (COMMAND.COM) that offered a user interface and executed batch files. Early versions supported only 160 KB or 320 KB floppy disks, a flat directory structure, and a very limited system call API.

Technically, MS-DOS was designed around the Intel 8086/8088’s segmented memory model, giving programs access to up to 640 KB of conventional memory, with the upper memory area reserved for system BIOS and hardware. The OS itself was not re-entrant and offered no process isolation: a single foreground program owned the machine at any given time, and the kernel simply provided file and device I/O calls. Devices were abstracted as special files (CON, PRN, AUX, NUL), allowing consistent access via the same system calls used for disk files. Its filesystem, FAT12, offered a simple, space-efficient design suitable for floppy media but imposed limits such as 8.3 filenames and small maximum volume sizes.

As the IBM PC platform expanded, MS-DOS evolved rapidly. Version 2.0 (1983), designed for the IBM XT with a hard drive, introduced FAT16, hierarchical subdirectories, file handles, and device drivers that could be dynamically loaded. Later releases added support for larger disks, expanded memory (via EMS/XMS standards), internationalization, and more sophisticated batch scripting. Version 3.x aligned with the IBM AT and its 80286 CPU, supporting 1.2 MB floppies, larger hard disks, and network redirectors. By version 4.0, MS-DOS began showing signs of strain under the growing complexity of PC hardware, and memory management became a recurring challenge due to the 640 KB conventional memory limit and the awkward use of extended and expanded memory schemes.

Despite being inherently single-tasking, MS-DOS was extended through third-party multitasking shells and Microsoft’s own attempts such as MS-DOS 4.0 Multitasking (rarely used). Eventually, MS-DOS served as the underlying runtime for Windows 3.x, which leveraged DOS for file and device I/O but implemented a cooperative multitasking GUI environment on top. With the release of Windows 95 and later, MS-DOS was gradually absorbed into Windows as a bootstrapping layer and compatibility subsystem. Nonetheless, MS-DOS’s simple architecture, reliance on BIOS and device drivers, and its widespread adoption made it the de facto standard for microcomputer operating systems throughout the 1980s, shaping software design and hardware standards for years to come.

The 8086 CPU from Intel is a 16-bit microprocessor and was designed between 1976 and 1978. The 8086 is the foundation of the x86 cpu architecture which is Intel's most successful line of processors.

The 8086 used the same microarchitecture as the 8-bit 8008, the 8080, and the 8085. This allowed assembly language programs to run seamlesly on the 8086. New instructions and features were added and the bus structure was designed to allow for collaboration with co-processors, such as the 8087 that was released later.