Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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@lang       : en
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                              Memory Management


Atari systems support two kinds of memory. Standard RAM (sometimes referred
to as 'ST RAM') is general purpose RAM that can be used for any purpose
including video and DMA. Current Atari architecture limits the amount of
standard RAM a system may have to 14MB.

Alternative RAM (sometimes referred to as 'TT RAM') can be accessed faster
than standard RAM but is not suitable for video memory or DMA transfers.

The Malloc() and Mxalloc() calls allocate memory blocks from the system
heap. Malloc() chooses the type of memory it allocates based on fields in
the program header (see later in this chapter). Mxalloc() allows the
application to choose the memory type at run-time.

MultiTOS uses memory protection to prevent an errant process from damaging
another. It is possible with Mxalloc() to dynamically set the protection
level of an allocated block.

Memory allocated with either Malloc() or Mxalloc() may be returned to the
system with Mfree(). Memory allocated by a process is automatically freed
when the process calls Pterm().