diff --git a/asminc/cbm510.inc b/asminc/cbm510.inc
index e1a86c487..627ba4991 100644
--- a/asminc/cbm510.inc
+++ b/asminc/cbm510.inc
@@ -15,6 +15,8 @@ IndReg          := $01          ; Controls indirect indexed load-store bank
 
 TXTPTR          := $85          ; Far pointer into BASIC source code
 FNAM            := $90          ; Far pointer to LOAD/SAVE file-name
+FNAM_SEG        := $92
+STATUS          := $9C          ; Kernal I/O completion status
 FNAM_LEN        := $9D          ; Holds length of file-name
 
 ; ---------------------------------------------------------------------------
diff --git a/asminc/cbm610.inc b/asminc/cbm610.inc
index b1b03eb1d..b031b2e9f 100644
--- a/asminc/cbm610.inc
+++ b/asminc/cbm610.inc
@@ -15,6 +15,8 @@ IndReg          := $01          ; Controls indirect indexed load-store bank
 
 TXTPTR          := $85          ; Far pointer into BASIC source code
 FNAM            := $90          ; Far pointer to LOAD/SAVE file-name
+FNAM_SEG        := $92
+STATUS          := $9C          ; Kernal I/O completion status
 FNAM_LEN        := $9D          ; Holds length of file-name
 
 ; ---------------------------------------------------------------------------
diff --git a/asminc/pet.inc b/asminc/pet.inc
index ee96d378c..c51010210 100644
--- a/asminc/pet.inc
+++ b/asminc/pet.inc
@@ -10,6 +10,7 @@ VARTAB          := $2A          ; Pointer to start of BASIC variables
 MEMSIZE         := $34          ; Size of memory installed
 TXTPTR          := $77          ; Pointer into BASIC source code
 TIME            := $8D          ; 60HZ clock
+STATUS          := $96          ; IEC status byte
 KEY_COUNT       := $9E          ; Number of keys in input buffer
 RVS             := $9F          ; Reverse flag
 CURS_FLAG       := $A7          ; 1 = cursor off
diff --git a/libsrc/c128/crt0.s b/libsrc/c128/crt0.s
index ba6a78ac5..b7e760176 100644
--- a/libsrc/c128/crt0.s
+++ b/libsrc/c128/crt0.s
@@ -9,7 +9,6 @@
         .import         push0, callmain
         .import         RESTOR, BSOUT, CLRCH
         .import         __MAIN_START__, __MAIN_SIZE__, __STACKSIZE__
-        .importzp       ST
 
         .include        "zeropage.inc"
         .include        "c128.inc"
@@ -92,7 +91,7 @@ L2:     lda     zpsave,x
 ; Place the program return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Reset the stack and the memory configuration.
 
diff --git a/libsrc/c128/status.s b/libsrc/c128/status.s
index c6f279230..eae91fb4d 100644
--- a/libsrc/c128/status.s
+++ b/libsrc/c128/status.s
@@ -1,5 +1,15 @@
 ;
-; Oliver Schmidt, 2012-09-30
+; Stefan Haubenthal, 2023-01-16
 ;
 
-        .exportzp       ST := $90       ; IEC status byte
+        .export         initst
+
+        .include        "c128.inc"
+
+.proc   initst
+
+        lda     #$00
+        sta     STATUS
+        rts
+
+.endproc
diff --git a/libsrc/c16/crt0.s b/libsrc/c16/crt0.s
index 1df1e5c62..35ececb9a 100644
--- a/libsrc/c16/crt0.s
+++ b/libsrc/c16/crt0.s
@@ -10,9 +10,9 @@
         .import         initlib, donelib
         .import         callmain, zerobss
         .import         MEMTOP, RESTOR, BSOUT, CLRCH
-        .importzp       ST
 
         .include        "zeropage.inc"
+        .include        "c16.inc"
 
 ; ------------------------------------------------------------------------
 ; Startup code
@@ -76,7 +76,7 @@ L2:     lda     zpsave,x
 ; Store the return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Restore the stack pointer.
 
diff --git a/libsrc/c64/crt0.s b/libsrc/c64/crt0.s
index 4e5c7c9d4..d57391b83 100644
--- a/libsrc/c64/crt0.s
+++ b/libsrc/c64/crt0.s
@@ -10,9 +10,9 @@
         .import         BSOUT
         .import         __MAIN_START__, __MAIN_SIZE__   ; Linker generated
         .import         __STACKSIZE__                   ; from configure file
-        .importzp       ST
 
         .include        "zeropage.inc"
+        .include        "c64.inc"
 
 
 ; ------------------------------------------------------------------------
@@ -62,7 +62,7 @@ L2:     lda     zpsave,x
 ; Place the program return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Restore the system stuff.
 
diff --git a/libsrc/c64/status.s b/libsrc/c64/status.s
index c6f279230..79d703489 100644
--- a/libsrc/c64/status.s
+++ b/libsrc/c64/status.s
@@ -1,5 +1,15 @@
 ;
-; Oliver Schmidt, 2012-09-30
+; Stefan Haubenthal, 2023-01-16
 ;
 
-        .exportzp       ST := $90       ; IEC status byte
+        .export         initst
+
+        .include        "c64.inc"
+
+.proc   initst
+
+        lda     #$00
+        sta     STATUS
+        rts
+
+.endproc
diff --git a/libsrc/cbm/getdevice.s b/libsrc/cbm/getdevice.s
index 08ba6d5f8..947ffbdc2 100644
--- a/libsrc/cbm/getdevice.s
+++ b/libsrc/cbm/getdevice.s
@@ -10,7 +10,8 @@
         .import         isdisk
         .import         opencmdchannel
         .import         closecmdchannel
-        .importzp       ST
+        .import         initst
+        .import         READST
         .importzp       tmp2
 
 ;------------------------------------------------------------------------------
@@ -40,8 +41,7 @@ next:   inx
 ; only [in|de]crement the reference count of the shared cmdchannel
 ; so we need to explicitly initialize ST here
 
-        lda     #$00
-        sta     ST
+        jsr     initst
 
         stx     tmp2
         jsr     opencmdchannel
@@ -49,10 +49,7 @@ next:   inx
         jsr     closecmdchannel
         ldx     tmp2
 
-; As we had to reference ST above anyway we can as well do so
-; here too (instead of calling READST)
-
-        lda     ST
+        jsr     READST
 
 ; Either the Kernal calls above were successfull or there was
 ; already a cmdchannel to the device open - which is a pretty
diff --git a/libsrc/cbm510/kreadst.s b/libsrc/cbm510/kreadst.s
index 66c0b880f..cb9363d42 100644
--- a/libsrc/cbm510/kreadst.s
+++ b/libsrc/cbm510/kreadst.s
@@ -16,11 +16,9 @@
 
         jsr     sys_bank
         sty     ktmp                    ; Save Y register
-        ldy     #$9C                    ; STATUS
+        ldy     #STATUS
         lda     (sysp0),y               ; Load STATUS from system bank
         ldy     ktmp
         jmp     restore_bank            ; Will set condition codes on A
 
 .endproc
-
-
diff --git a/libsrc/cbm510/ksetnam.s b/libsrc/cbm510/ksetnam.s
index c338c0de4..e0e488b9e 100644
--- a/libsrc/cbm510/ksetnam.s
+++ b/libsrc/cbm510/ksetnam.s
@@ -22,7 +22,7 @@
         sty     ktmp
 
         txa
-        ldy     #$90                    ; FNAM
+        ldy     #FNAM
         sta     (sysp0),y
 
         lda     ktmp
@@ -33,13 +33,10 @@
         ldy     #$92                    ; FNAM_SEG
         sta     (sysp0),y
 
-        ldy     #$9D                    ; FNAM_LEN
+        ldy     #FNAM_LEN
         pla
         sta     (sysp0),y
         ldy     ktmp
         jmp     restore_bank
 
 .endproc
-
-
-
diff --git a/libsrc/cbm510/status.s b/libsrc/cbm510/status.s
new file mode 100644
index 000000000..a21105710
--- /dev/null
+++ b/libsrc/cbm510/status.s
@@ -0,0 +1,21 @@
+;
+; Stefan Haubenthal, 2023-01-16
+;
+
+        .export         initst
+
+        .include        "extzp.inc"
+        .include        "cbm510.inc"
+
+.proc   initst
+
+        ldx     IndReg
+        ldy     #$0F
+        sty     IndReg          ; Switch to the system bank
+        ldy     #STATUS
+        lda     #$00            ; Initialize value
+        sta     (sysp0),y
+        stx     IndReg
+        rts
+
+.endproc
diff --git a/libsrc/cbm610/crt0.s b/libsrc/cbm610/crt0.s
index 0ad343d7f..15f1dfb7b 100644
--- a/libsrc/cbm610/crt0.s
+++ b/libsrc/cbm610/crt0.s
@@ -394,7 +394,7 @@ _exit:  pha                     ; Save the return code
 ; Place the program return code into BASIC's status variable.
 
         pla
-        ldy     #$9C            ; ST
+        ldy     #STATUS
         sta     (sysp0),y
 
 ; Set up the welcome code at the stack bottom in the system bank.
diff --git a/libsrc/cbm610/kreadst.s b/libsrc/cbm610/kreadst.s
index d9bbf7c2d..44dc1ebab 100644
--- a/libsrc/cbm610/kreadst.s
+++ b/libsrc/cbm610/kreadst.s
@@ -16,11 +16,9 @@
 
         jsr     sys_bank
         sty     ktmp                    ; Save Y register
-        ldy     #$9C                    ; STATUS
+        ldy     #STATUS
         lda     (sysp0),y               ; Load STATUS from system bank
         ldy     ktmp
         jmp     restore_bank            ; Will set condition codes on A
 
 .endproc
-
-
diff --git a/libsrc/cbm610/ksetnam.s b/libsrc/cbm610/ksetnam.s
index 97ecf0126..d3542c83d 100644
--- a/libsrc/cbm610/ksetnam.s
+++ b/libsrc/cbm610/ksetnam.s
@@ -22,7 +22,7 @@
         sty     ktmp
 
         txa
-        ldy     #$90                    ; FNAM
+        ldy     #FNAM
         sta     (sysp0),y
 
         lda     ktmp
@@ -30,14 +30,13 @@
         sta     (sysp0),y
 
         lda     ExecReg                 ; Assume name is always in this segment
-        ldy     #$92                    ; FNAM_SEG
+        ldy     #FNAM_SEG
         sta     (sysp0),y
 
-        ldy     #$9D                    ; FNAM_LEN
+        ldy     #FNAM_LEN
         pla
         sta     (sysp0),y
         ldy     ktmp
         jmp     restore_bank
 
 .endproc
-
diff --git a/libsrc/cbm610/status.s b/libsrc/cbm610/status.s
new file mode 100644
index 000000000..b8583159e
--- /dev/null
+++ b/libsrc/cbm610/status.s
@@ -0,0 +1,21 @@
+;
+; Stefan Haubenthal, 2023-01-16
+;
+
+        .export         initst
+
+        .include        "extzp.inc"
+        .include        "cbm610.inc"
+
+.proc   initst
+
+        ldx     IndReg
+        ldy     #$0F
+        sty     IndReg          ; Switch to the system bank
+        ldy     #STATUS
+        lda     #$00            ; Initialize value
+        sta     (sysp0),y
+        stx     IndReg
+        rts
+
+.endproc
diff --git a/libsrc/pet/checkst.s b/libsrc/pet/checkst.s
index 8d9d9a4f3..146a358e2 100644
--- a/libsrc/pet/checkst.s
+++ b/libsrc/pet/checkst.s
@@ -6,12 +6,12 @@
 ;
 
         .export         checkst
-        .importzp       ST
 
+        .include        "pet.inc"
 
 .proc   checkst
 
-        lda     ST
+        lda     STATUS
         beq     @L1
         lda     #5              ; ### Device not present
         sec
diff --git a/libsrc/pet/crt0.s b/libsrc/pet/crt0.s
index e56a7eca4..18b9f7e05 100644
--- a/libsrc/pet/crt0.s
+++ b/libsrc/pet/crt0.s
@@ -8,7 +8,6 @@
         .import         zerobss, push0
         .import         callmain
         .import         CLRCH, BSOUT
-        .importzp       ST
 
         .include        "zeropage.inc"
         .include        "pet.inc"
@@ -80,7 +79,7 @@ L2:     lda     zpsave,x
 ; Store the program return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Restore the stack pointer.
 
diff --git a/libsrc/pet/kreadst.s b/libsrc/pet/kreadst.s
index 38f6bfb19..38e399bae 100644
--- a/libsrc/pet/kreadst.s
+++ b/libsrc/pet/kreadst.s
@@ -5,14 +5,12 @@
 ;
 
         .export         READST
-        .importzp       ST
 
+        .include        "pet.inc"
 
 .proc   READST
 
-        lda     ST
+        lda     STATUS
         rts
 
 .endproc
-
-
diff --git a/libsrc/pet/status.s b/libsrc/pet/status.s
index 2e2e858a0..d7324b93c 100644
--- a/libsrc/pet/status.s
+++ b/libsrc/pet/status.s
@@ -1,5 +1,15 @@
 ;
-; Oliver Schmidt, 2012-09-30
+; Stefan Haubenthal, 2023-01-16
 ;
 
-        .exportzp       ST := $96       ; IEC status byte
+        .export         initst
+
+        .include        "pet.inc"
+
+.proc   initst
+
+        lda     #$00
+        sta     STATUS
+        rts
+
+.endproc
diff --git a/libsrc/plus4/crt0.s b/libsrc/plus4/crt0.s
index 6b44a2b7e..71e734353 100644
--- a/libsrc/plus4/crt0.s
+++ b/libsrc/plus4/crt0.s
@@ -11,7 +11,6 @@
         .import         __INTERRUPTOR_COUNT__
         .import         __MAIN_START__, __MAIN_SIZE__   ; Linker generated
         .import         __STACKSIZE__                   ; Linker generated
-        .importzp       ST
 
         .include        "zeropage.inc"
         .include        "plus4.inc"
@@ -106,7 +105,7 @@ L2:     lda     zpsave,x
 ; Place the program return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Restore the stack pointer.
 
diff --git a/libsrc/plus4/kreadst.s b/libsrc/plus4/kreadst.s
index 2571f80f5..f833b8126 100644
--- a/libsrc/plus4/kreadst.s
+++ b/libsrc/plus4/kreadst.s
@@ -7,12 +7,11 @@
         .export         READST
 
         .include        "plus4.inc"
-        .importzp       ST
 
 ; Read the status byte from the zero page instead of banking in the ROM
 
 .proc   READST
-        lda     ST                      ; Load status
+        lda     STATUS                  ; Load status
         rts                             ; Return to caller
 .endproc
 
diff --git a/libsrc/plus4/status.s b/libsrc/plus4/status.s
index c6f279230..0eceb6ba9 100644
--- a/libsrc/plus4/status.s
+++ b/libsrc/plus4/status.s
@@ -1,5 +1,15 @@
 ;
-; Oliver Schmidt, 2012-09-30
+; Stefan Haubenthal, 2023-01-16
 ;
 
-        .exportzp       ST := $90       ; IEC status byte
+        .export         initst
+
+        .include        "plus4.inc"
+
+.proc   initst
+
+        lda     #$00
+        sta     STATUS
+        rts
+
+.endproc
diff --git a/libsrc/vic20/crt0.s b/libsrc/vic20/crt0.s
index c5486063b..a98a1acb3 100644
--- a/libsrc/vic20/crt0.s
+++ b/libsrc/vic20/crt0.s
@@ -10,9 +10,9 @@
         .import         RESTOR, BSOUT, CLRCH
         .import         __MAIN_START__, __MAIN_SIZE__   ; Linker generated
         .import         __STACKSIZE__                   ; Linker generated
-        .importzp       ST
 
         .include        "zeropage.inc"
+        .include        "vic20.inc"
 
 ; ------------------------------------------------------------------------
 ; Startup code
@@ -72,7 +72,7 @@ L2:     lda     zpsave,x
 ; Place the program return code into BASIC's status variable.
 
         pla
-        sta     ST
+        sta     STATUS
 
 ; Restore the stack pointer.
 
diff --git a/libsrc/vic20/status.s b/libsrc/vic20/status.s
index c6f279230..17c015a1f 100644
--- a/libsrc/vic20/status.s
+++ b/libsrc/vic20/status.s
@@ -1,5 +1,15 @@
 ;
-; Oliver Schmidt, 2012-09-30
+; Stefan Haubenthal, 2023-01-16
 ;
 
-        .exportzp       ST := $90       ; IEC status byte
+        .export         initst
+
+        .include        "vic20.inc"
+
+.proc   initst
+
+        lda     #$00
+        sta     STATUS
+        rts
+
+.endproc