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DOS and BIOS had some pretty crappy interrupt calls for Serial port access and as DOS was single threaded and you could hang the PC if not careful. In timing cr
by boznz 5y ago
DOS and BIOS had some pretty crappy interrupt calls for Serial port access and as DOS was single threaded and you could hang the PC if not careful. In timing critical cases you were safer accessing the serial controller directly.. Of course strictly verboten under any real OS and one of the reasons a lot of older timing critical software was problematic to move to windows or other hardware.
- deadlyllama 5y agoNot just timing critical stuff. BIOS calls for serial were slow, character at a time. If you wanted to fill a buffer and keep processing you wrote your own interrupt driven serial code or used a good library. No serious software on DOS would use the BIOS serial code. This sort of thing was just normal. No multitasking so you had full control of the hardware. Third party libraries or custom code for serial, sound, graphics, often keyboard. Drop into assembly for extra speed. DOS was basically a library for filesystem access, process creation and limited memory management! I still have 1.193180Mhz burned in my brain...
- ksec 5y ago>This sort of thing was just normal. No multitasking so you had full control of the hardware. Third party libraries or custom code for serial, sound, graphics, often keyboard. Drop into assembly for extra speed. DOS was basically a library for filesystem access, process creation and limited memory management! I sometimes think if we will one day cycle back to that model. It was at least an era where I thought I had some understand of computer. Now I seriously dont. But it works.