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Portable Plus - Additional RAM
03-23-2015, 10:48 PM
Post: #23
RE: Portable Plus - Additional RAM
(03-23-2015 09:38 PM)Dave Frederickson Wrote:  Squish Plus isn't an executable, it's a device driver that creates a compressed drive, like Stacker and DriveSpace.
I see, that's what I assumed as well. (It long predates the DOS preload API, but this doesn't really matter in regard to the general functionality of such a device driver.)

However, there are two basic modes of execution for code stored in ROM. If the software was developed with a clear line between code and data segments and its image is either small enough or modular to be separated into "overlays", the software can often be adapted to execute out of the (possibly paged) ROM, that is "execute in place", with only a tiny fraction of RAM being allocated elsewhere for the necessary runtime data. This keeps the DOS memory footprint very small, but it requires some adaptations to the software. If such adaptations are not possible, or code and data are intermixed for other reasons (f.e. in the case of patchable, self-modifying or otherwise highly dynamic or highly size-optimized code), the software may be still stored in ROM, but it needs to be copied to RAM before execution. In this case, the DOS memory footprint is considerably higher and not different from the footprint of software loaded from disk - apparently 36 KB for Squish Plus (according to the Portable Paper advertisment). That's why I was asking how the ROMed version of Squish Plus is implemented.
Quote:More RAM will need to be allocated to main memory in order to use this tool with TC1.5.
Do you know how much memory needs to be reallocated this way?



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RE: Portable Plus - Additional RAM - matthiaspaul - 03-23-2015 10:48 PM

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