The demo is divided in the boot loader and demo 3 parts
The demo is intended to work with a 64K RAM (or more) PCjr. Booting from its own boot loader is needed to save precious memory. DOS alone takes ~20K of RAM. That is 30% of the total memory. You don’t want to waste that memory.
The Cromemco System Three is a Z-80 based computer. Which is nice, because I always wanted to learn Z-80 (this is my second Z-80 computer, the other one is a MSX2).
But What I like about the Cromemco is how well-built it is. I love it.
The computer is that not big, but it is a very heavy computer.
At the moment I don’t have the needed cables to test it. If I can’t find them, I might be able to build them myself (or not). If manage to get the cables, and provided that the computer works, I promise to write a game or something for it 🙂
But how fast is an IBM PC 5150 compared to a PCjr ? or to a Tandy 1000? or how fast is the Tandy 1000 HX in fast mode (7.16Mhz) compared to the slow mode (4.77Mhz) ? Or how fast is a nop compared to a cwd ?
I created a test (perf.asm) that measures the performance of different opcodes and run it on different Intel 8088 machines. I run the test multiple times just to make sure the results were stable enough. All interrupts were disabled, except the Timer (of course). And on the PCjr the NMI is disabled as well.
IBM PCjr zero-day data-destroy vulnerability (AKA: Joykill).
This vulnerability allows local and remote attackers to destroy the contents of the floppy diskette. User interaction is required to exploit this vulnerability. The issue results from the lack of proper validation when starting the manufacturing system test.
With PVM with released an intro for the Tandy 1000 HX.
The Tandy 1000 HX uses the Intel 8088-2 CPU. Which is a suuuuper slow CPU (slower than the 8086). With all its wait states and its limitations on the video card (no hardware sprites, no charset redefinition) it makes it comparable with a Commodore 64. In fact, for certain things a Commodore 64 if way faster.