Re: ReRe: 0.9.0c

[Gero Kuhlmann <gero@gkminix.han.de>]

Hello,

Roland Rohde <roro@artificial-organs.de> wrote:
> What is the meaning of maxsize and minsize?
> If they are driver dependent, how are they determined?

This is one of the major reasons why the final 0.9 has not yet been released:
the documentation is still missing. Anyway, minsize gives the size in bytes
the network driver needs in memory after it has been started and initialized.
This value can be determined by running the driver under DOS. Then, the DOS
command 'mem /c' prints the amount of memory occupied by the driver. You can
add 1024 to that value for DOS internal use and some safety margin and you end
up with the minsize value. maxsize is the amount of memory to allocate before
the network driver gets loaded and started. To determine this value is rather
complicated. With EXE type drivers (packet and NDIS drivers), this amount can
be found in the EXE file header. Therefore, for those drivers a maxsize value
can safely be ommited, because makerom can determine it by itself. It's
different for COM style drivers, since there is no header included. If it's
a normal COM program (again either packet or NDIS driver), then you should
use the program file size and add some space for DOS internal use (PSP) and
then some stack space. It is probably safe for most drivers to add 4096 to
the file size in order to determine the maxsize value. However, if the network
driver initialization code needs more stack space, this might not be enough.
Also, it is possible to compress COM programs with PKLITE. Drivers compressed
this way need much more loading memory. Unfortunately, there is no easy way
of determining how much is required. The best would be (since the bootrom
gets compressed anyway) to uncompress the PKLITE'ed program before using it
with netboot. However, the next release of netboot will contain some (probably
too simple) mechanism to detect and hopefully corrct for compressed executables.

In general, it is safe to ommit the minsize and maxsize values. They are
intended to allow for better memory organization when loading more than one
DOS program. However, with some large network drivers the maxsize value
determined automatically by makerom might be too small, so in those cases
it might be useful to adjust it.

Hope, this helps. This text really belongs into the netboot documentation.

gero.

-- 
"Classic." A book which people praise and don't read.
  - M. Twain
--
Gero Kuhlmann, Hannover     0511/6497525 (Voice)        gero@gkminix.han.de
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