sys.txt

GNU FreeDOS兼容MS DOS很好的东东.

SYS documentation by Jeremy Davis
Updated by Bart Oldeman

SYS's standard behavior is very similar (though in
my opinion improved) to that of other DOSes.
SYS (no options) should provide a general usage,
and SYS CONFIG /help (or SYS CONFIG /?) should
provide usage for the new configuration options.

Admittedly its brief, but it is there.
Below is a more detailed documentation on its
usage (from memory, but I believe it is close to right).
The best documentation (and maybe only) is the
source itself.


The simplest usage:

SYS dest:

dest should be the drive (A:, B:, C:, ...) you wish
to be bootable with FreeDOS (kernel & command.com)
When using this form, KERNEL.SYS and COMMAND.COM
must reside either in the current directory (which
is searched first) or in recent revisions may also
be in the root directory of the current drive.

Complete form:

SYS [source] dest: [bootsect [BOTH]]

Here dest is the same as before, but this time
you specify where KERNEL.SYS and COMMAND.COM are.
Source may simply be a drive (in this case it
is similar to PC & MS SYS).  The current directory
of the specified drive is first searched for
KERNEL.SYS & COMMAND.COM and if not found then
the root directory of the specified drive is tried.
Alternatively, you may specify a path (either fully
qualified or relative) to where KERNEL.SYS and
COMMAND.COM may be found; note that this should 
only search this directory and will fail if they
are not found, ie it will not check for them on
the root directory of the drive specified when
a path is given.  It should also fail if the
source and destination drive are both the same
and would result in trying to SYS from the root
to the root (ie trying to SYS from C:\ to C:\).

If you specify a name for "bootsect", for instance,
bootsect.fd, SYS will write to that file instead of
the real boot sector. You will obtain a 512-byte file
containing the boot sector, which can then be used
for dual booting or diagnostic purposes.

If you also specify BOTH, sys will write to both
the image file and the boot sector.


Kernel Configuration Options:

Simplest form:

SYS CONFIG

This will simply display the current settings
for the file KERNEL.SYS in the current directory.
It is useful to see what the options are currently
set to, what options are supported, and should
show valid values along with defaults (defaults are
the valid values with a '*' next to them).

Optionally specify file:

SYS CONFIG [drive][path]KERNEL.SYS

This form behaves as above, except will display
the settings for the kernel file you specify.
drive and path are optional, and generally just
a \ will be used to indicate root directory of
current drive.  KERNEL.SYS specifies the filename
of the kernel, which may not be "KERNEL.SYS",
for example when testing you want to alter
KERNTEST.SYS and later copy (or rename) this to
KERNEL.SYS for booting.


Changing options:

SYS CONFIG OPTION1=value [OPTION2=value ...]

This form will read the current settings from
the kernel (KERNEL.SYS in the current directory)
and set the options specified to the value given.
If the value is potentially invalid (too large, too
small, etc) then a warning will be displayed, but
the change will still occur.  The kernel file is
only updated if at least one option is different from the
current settings.  If you wish to force the kernel
file to be written to, then set the same option
twice (OPTION1=oddvalue OPTION1=desiredvalue), with
the 1st time the value being different from the
current one and the rightmost one being the desired
value.  Currently three options are supported.
Note: currently only the 1st three letters are
actually checked, so they may be abreviated to
DLA, SHO, and SKI and with my recent patch you may
specify the value as either a decimal number 0,10,255,...
or as a hexidecimal number 0x0,0xA, 0xFF...

DLASORT which may be set to 0 or 1
DLASORT=0 or DLASORT=1
This option is for specifying whether Drive Letter
Assignment should follow the normal MSDOS way of
all primary partitions across drives and then
extended partitions, or the more logical
all partitions (primary & extended) on the 1st 
drive, then repeat for all following drives 
(all primary & extended, then try next drive).
0 corresponds to MS way and 1 corresponds to first
drive completely, then next ...

SHOWDRIVEASSIGNMENT which may be 0 or 1
SHOWDRIVEASSIGNMENT=0 or SHOWDRIVEASSIGNMENT=1
If 1 then the normal drive assignment information
is displayed upon booting.  If 0 then this information
is supressed (not shown).

SKIPCONFIGSECONDS which may be -128 to 127.
A negative value ( < 0 ) indicates that F5/F8
processing will be skipped (the kernel won't check
if you pressed these keys, so you can't skip config
file (CONFIG.SYS) processing).  A 0 means you must
have pressed the key precisely for when the kernel
checks for it - essentially skipping, though a well
timed finger will still get to use it.  And any value
greater than 0 is the number of seconds the kernel will
display the prompt and wait for you to press the key
before assuming you didn't.

FORCELBA which may be 0 or 1
FORCELBA=0 or FORCELBA=1
If 1 then the kernel will use LBA (extended INT13)
techniques to address all partitions if possible,
even if these have a non-LBA partition type and
are completely below cylinder 1023 (usually the 8GB
boundary). This is 0 by default, for compatibility
reasons. Setting this to 1 may bypass some buggy 
BIOSes and gives slightly better performance.

GLOBALENABLELBASUPPORT which maybe 0 or 1
GLOBALENABLELBASUPPORT=0 or GLOBALENABLELBASUPPORT=1
If 0 then LBA will be completely disabled, irrespective
of the FORCELBA setting. You need this if FreeDOS thinks
you have LBA available, but in reality you do not.
This setting is set to 1 by default.

Example: To set the kernel in the current directory
to have a timeout of 5 seconds (default is 2) run
SYS CONFIG SKI=5


Changing options of specified file:

SYS CONFIG [drive][path]KERNEL.SYS OPTION1=value ...]

This is just like previous section on setting options,
except the first argument after CONFIG specifies which
kernel file to use.  The filename is the same form used
for displaying options of specified kernel file described
above.

Example2: To set a kernel in the root directory to
not show drive assignment and change the timeout
to never check
SYS CONFIG \KERNEL.SYS SKI=-1 SHOWDRIVEASSIGNMENT=0x0