UPDATE: It was quite hard to find reference information about all this. I vaguely remember reading it in one of the Peter Norton books at the time, but I can

UPDATE: It was quite hard to find reference information about all this. I vaguely remember reading it in one of the Peter Norton books at the time, but I can't really find them. The most relevant thing I can still find on todays internet is this: https://www.pcjs.org/documents/books/mspl13/msdos/advdos/ https://www.pcjs.org/documents/books/mspl13/msdos/advdos/ chapter 3: ... the operating system simply makes the worst-case assumption and gives .COM programs everything that is available. If a .COM program wants to use the EXEC function to invoke another process, it must first shrink down its memory allocation ...