![]() The look and feel mimics that of Microsoft Windows. The graphical user interface (GUI) of SymbOS works in a fully object-oriented manner. Because of the FAT support data exchange with other computers is quite easy, as most 32 and 64 bit operating systems do support the three FAT file systems. Also, the ability to administer files with a size of up to 2 GB is uncommon for an 8-bit system. With the last one, SymbOS can address mass storage devices with a capacity of up to 128 GB. ![]() SymbOS supports the file systems CP/M, AMSDOS, and File Allocation Table (FAT) 12-16-32, on all platforms. The SymbOS kernel supports synchronous and asynchronous IPC. This is necessary inside a multitasking environment to avoid organization problems with the stack, global variables and shared system resources. It makes transparent access to memory and functions placed in other 64 KB banks possible.Ĭommunication between different tasks and the operating system usually does not take place via calls, but is done via messages. That makes it possible to reserve up to 63 KB in one piece.īanking management ensures that the system can administer memory with a size of up to one megabyte, even though the Z80 CPU has only a 16-bit address bus. Applications are always running in a secondary 64 KB RAM bank, where no memory space is occupied by the operating system or the video memory. Memory management divides the entire RAM into small 256 byte blocks, which can be assigned dynamically. Tasks with low priority get CPU time only if all tasks with higher priorities are not then working. Because of this combination it is possible to assign priorities. It does that, if it's finished with its current job or waiting for a certain event. Cooperatively means that a task stops using CPU time by itself. Preemptive means that tasks are interrupted after a certain amount of time by the operating system, in order to share the CPU time with other tasks. Task management įor task management, a combination of preemptive and cooperative multitasking was chosen, which makes different task priorities possible. SymbOS includes a microkernel, which can perform task management, memory management and inter-process communication. In this way, computers like the Amstrad CPC and PCW, MSX, Enterprise or SAM Coupé can access hundreds or thousands of kilobytes of memory. The restriction of Z80 system to a 64 KB address space can be solved with bank switching. The existence of an alternative register set accelerates context switching between tasks dramatically. While the MOS Technology 6502 cannot move the stack pointer, the Z80 can freely relocate it to any position in memory, which makes it easier to implement preemptive multitasking. Yet, it was generally unavailable for home computers. ![]() The MP/M OS proved that multitasking on the Z80 CPU was possible. For example, AmigaOS also lacks memory protection. Features such as memory protection, which the Z80 lacks, are not essential in such an OS. ![]() One of the goals of the project is to allow these old machines to be used like a modern PC, using hardware extensions.Īlthough only an 8-bit CPU, the Z80 can run a preemptive multitasking operating system. SymbOS is one of the largest retro computing software projects of recent years. The release in 2006 proved that such a "mini windows" system is possible on a then 20-year-old home computer with only quantitative limitations. GEOS contributed to the motivation, but the structure and features of SymbOS aren't similar to that system. SymbOS was originally started as an experiment to find out to what extent it is possible to implement a multitasking operating system with a windowed GUI on an 8-bit computer from 1985. ( October 2018) ( Learn how and when to remove this template message) Unsourced material may be challenged and removed. Please help improve this section by adding citations to reliable sources. SymbOS contains a Microsoft Windows like graphical user interface (GUI), supports hard disks with a capacity of up to 128 GB and can already be booted on an unexpanded Amstrad CPC-6128, a 128K- MSX2 and an Amstrad PCW.Īs of Augit is available for the Amstrad CPC series of computers, all MSX models starting from the MSX2 standard, MSX with V9990 graphics chip, all Amstrad PCW models, CPC-TREX, C-ONE and the Enterprise 64/128 computers. SYmbiosis Multitasking Based Operating System ( SymbOS) is a multitasking operating system for Zilog Z80-based 8-bit computer systems.Ĭontrary to early 8-bit operating systems it is based on a microkernel, which provides preemptive and priority-oriented multitasking and manages random-access memory (RAM) with a size of up to 1024 KB. Screenshot of the SymbOS desktop on the Amstrad CPCģ.1 / 30 December 2021 18 months ago ( )Īmstrad CPC, MSX, Amstrad PCW, Enterprise 64/128 ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |