Back to home page

DOS ain't dead

Forum index page

Log in | Register

Back to the forum
Board view  Mix view

Howto receive 4GB memory as one chunk, DPMI + Watcom C (Developers)

posted by DosWorld(R), 06.02.2019, 23:06


I had develop software (text editor) and I want open very huge files. My problem is - dpmi hosts does not return memory as one chunk. So, watcom memory manager use memory only from one chunk (~64mb, with causeway extender - 220mb). How to received full memory as one chunk?

My target - open 3-3.5gb text file. Now, I can open only little bit more 40mb :(
May be somebody have any advise..

As I understood, need something like virtual memory mapping. (But what is it and how prepare it?)

PS: One time I receive all memory as one chunk, but in very strange way: I compile programm for watcom "compact" memory model for dos4g-extender and run it via HX's dpmild32. I had read recomendations does not use this memory model (because library is not ready, but printf works for me!) and I dont known how to receive access to first megabyte (0000:004xx, b800:0000) in this memory model. At the same time, programm compiled for "hxdos" had 64mb chunks.

PPS: For memory size check I am use source code from Watcom Programmers Guide (I hope, many people see it).

PPPS: I had receive big speed degradation for watcom's malloc, after 500k allocated strings. I think, it will be unusable after 1m malloc's. It is looks like watcom manage memory via linked list structure. So, I want refuse using watcom malloc and switch to my own memory manager (may be he not so fast, but he remember where is stored first free memory block).

Make DOS great again!


Complete thread:

Back to the forum
Board view  Mix view
15889 Postings in 1469 Threads, 269 registered users, 90 users online (0 registered, 90 guests)
DOS ain't dead | Admin contact
RSS Feed
powered by my little forum