[syslinux] Re: Menu system limitations

Murali Krishnan Ganapathy gmurali at cs.uchicago.edu
Wed Apr 28 08:49:42 PDT 2004

The only limit AFAIK is memory. All memory is allocated statically at 
compile time. The maximum size for a COM file is 64K. The code plus all 
the data should fit into this. Assuming about 256 bytes per item (that 
is on the higher side), and 10K for code, and about 6K for the stack, 
you have a limit of about 200 items. If you go over the limit, you 
should not be able to compile the code (the compiler should complain 
that your final executable is more than 64K).

If your items can be dynamically generated, then you may be able to 
leverage the additional 64K available for COM files (this would mean 
changing the code, since currently the code assumes a 16bit pointer). If 
you need more than 200 and odd items and they are static, I see one 
simple workaround...

* Cut your menu tree at some level (say level 2). Then you will have a 
mainmenu.com which displays the first two levels of the menu, and for 
each possible level 2 choice, you will have a different menu.com file. 
Choosing a item from the mainmenu, will call one of the helper menu.com.

- Murali

Aaron McSorley wrote:

>  Are there any hard limits to the amount of items and menus that can
>be in one comboot menu file. Or does this depend on you hardware setup.
>Currently I have sixteen menus and eightyfive items in one comboot file.
>It's been running well for almost a month (good job guys). The number of
>items will grow significantly and I want to be aware of any limitations.
> -Aaron

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