RT11 sysgen and disk partitions

[Jerome H. Fine]

 >Megan wrote:

>>So I imagine any device drive with the X at the end is the better one to
>>use with the XM monitor?  Or is it mandatory to use X device drivers in
>>the XM monitor?
>>
>It is mandatory... the system knows to append an X to any two-character
>device name
>  
>
Jerome Fine replies:

Since Megan mentioned the monitors for V05.06, these ddX.SYS
device drivers are also used with the RT11ZM.  Note that both
RT11XM and RT11ZM are known as mapped monitors.  In addition,
also starting with V05.06 (although I have never used them myself),
RT11XB and RT11ZB are also mapped, if I understand the
documentation correctly.  I presume that these last two monitors
also use the ddX.SYS device drivers.

All the other monitors are unmapped and use the dd.SYS device drivers.

>>So this brings up another question: I've noticed that I don't explicitly
>>need to LOAD device drivers for the devices I want to use when I boot
>>RT-11.  In particular, I don't need to LOAD DD when I want to use the
>>TU58 simulator.  Are they found and loaded automatically when the OS
>>boots, or...?
>>
>Most utilities and user applications know to .FETCH device drivers they
>need in order to do their task.  After they are done, the drivers are
>.RELEAsed.  If they are LOADed before the program is executed, a .FETCH
>and .RELEA are no-ops.
>  
>
I would modify that to be almost all DEC utilities (probably ALL)
include .Fetch and .Release calls.  As for user applications, certainly
the ones which are widely used will likely include the calls, but if
you get an "Invalid device error" and the LOAD command fixes
the problem, you can figure out the situation for yourself.

One other minor point is that I seem to remember that system jobs
are not allowed to perform .Fetch calls to the monitor.  If a user
uses VBGEXE to run a normal program as a system job, then all
device handlers that are used must first be LOADed.

>If they aren't loaded and aren't .FETCHed, then they simply are not in
>memory.
>  
>
Which does not mean the device drivers are unavailable,
simply not immediately ready.  This means that with
device drivers such as DU(X).SYS using the RQDX1 or
RQDX2, it is best to use the LOAD command if repeated
use is expected since there are many seconds of delay
to initialize the controller.  The RQDX3 is a bit faster.

NOTE that I agree with everything the Megan stated, I
was just adding a bit more detail.

Sincerely yours,

Jerome Fine
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