RT11 sysgen and disk partitions

[Megan]

>>It is mandatory... the system knows to append an X to any two-character
>>device name

For casual users of RT, this is the rule.  For more experienced users,
there is a way of changing the 'X' to some other character.  So, you
could have dd.SYS, for SB and FB, ddX.SYS for XB, XM, ddZ.SYS for ZB
and ZM, or some other mapping...

It is not trivial, as many drivers have the 'X' built in, but it is
possible.


>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.

Right...

>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.

Good point... that is true.  But it is possible for system and
foreground jobs to fetch handlers if certain steps are taken
and if the program is designed a certain way... but it is not
for the faint of heart.  I believe I used the technique in my
RTEFTP program... I'll have to check on the specifics.

>>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

Thanks... good point.

>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.

                                        Megan Gentry
                                        Former RT-11 Developer

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| Megan Gentry, EMT/B, PP-ASEL,ST| email: mbg at world.std.com         |
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