Jim Leonard
2017-02-08 23:31:40 UTC
As the subject says. Since MS-DOS ever since version 2.0 has memory management functions (INT 21h/AH=48h, INT 21h/AH=49h, and INT 21h/AH=4Ah), why did Borland feel it necessary to implement their own heap manager?
The only possible reason I can think of is that Borland's management only uses 8 bytes of overhead instead of DOS's 16 bytes per overhead (per MCB), so I guess the advantage was that you could use 8 less bytes per allocation, and also allow a minimum allocation of 8 bytes instead of DOS's 16 bytes. The thing is, the heap manager compiles to nearly 1K, so it seems like this would have eaten up any savings gained by a smaller heap structure...? Any thoughts or comments welcome.
The only possible reason I can think of is that Borland's management only uses 8 bytes of overhead instead of DOS's 16 bytes per overhead (per MCB), so I guess the advantage was that you could use 8 less bytes per allocation, and also allow a minimum allocation of 8 bytes instead of DOS's 16 bytes. The thing is, the heap manager compiles to nearly 1K, so it seems like this would have eaten up any savings gained by a smaller heap structure...? Any thoughts or comments welcome.