Date   : Wed, 22 Dec 1982 00:52:07-EST (Wed)
From   : Rick Conn <rconn@BRL>
Subject: Re: USER # in BIOS

Dick,

       The problem you describe lies in the Warm Boot routine within the
BIOS.  Whenever the CCP is entered via either the Warm or Cold Boot routines
in the BIOS, the user/disk flag is carried to it in the C register.

       I do not have the problem you describe.  Warm Boots return me to
the user/disk I was logged into.  My BIOS code in the Warm and Cold Boots
which does this is:

COLD BOOT:
       cbdisk  equ     0       ;enter user 0 (high 4 bits), disk A
                               ; (low 4 bits) on Cold Boot (Startup)
       cdisk   equ     4H      ;address of user/disk flag on Page 0
       ...
       mvi     a,cbdisk        ;select default user/disk
       sta     cdisk           ;set user/disk flag
       ...
       jmp     gocpm
WARM BOOT:
       ...
       jmp     gocpm           ;Warm Boot reloads CCP and BDOS
GOCPM:
       ...                     ;Init:
       ...                     ;  JMP at 0, JMP at 5, others
       lda     cdisk           ;get current user/disk flag
       mov     c,a             ;... in C for CCP entry
       ...
       jmp     ccp             ;enter CCP with user/disk in C

       In this type of environment, I have the flexibility of setting
cbdisk to anything I want, such as 21H to come up in user 2 on drive B
when I cold boot or 0A0H to come up in user 10 on drive A on cold boot.

       Hope this answers your question.

               Rick