This was a fun project I did for an employer many years ago. He had an application which would be getting hit from the Internet so fast that he didn't think either Windows or Linux could keep up. Therefore, he wanted to write an operating system which was geared to his specific application, and nothing else.
At the time this was written, there were still a significant number of 8086's, 80286's and 80386's on the market. Therefore, the operating system would first have to determine what type of hardware it was running on, then put up a message telling the user it wouldn't work if it was not at least a 386.
The operating system was launched from MS-DOS, but it quickly took over the entire memory, so in usage the MS-DOS would go away. In practice, I start the OS by allocating as large a chunk of memory as I could in MS-DOS, then memory allocation started in that chunk. Since I could start allocating the physical memory any place I wanted, I allocated this memory first. This allowed me to escape to MS-DOS during the early stages of testing.
I remember the memory allocation procedure were complete. That is, if the user referenced memory, then the OS would put some physical memory at the logical address. I'm not sure how much was completed.
©2008, Baldwin Computer Science
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