Minor tweekas after last commit

* Moved DIOMED_MID variable - so it would be overwritten at start of main Calculation
* Removed code in SYS_GETDIOMED1A - since SYS_GETDIOMED6A did exactly this anyway
* Removed code that set MID_HD - since it would now already be set.

Source/HBIOS/hbios.asm

@@ -5243,6 +5243,8 @@ SYS_GETDIOFN:
 ;     E: SLICE, ignored if media is not a hard disk
 ;   RETURNS:
 ;     A: STATUS, -6 (parameter out of range) - if Slice is invalid
+	Other errors Include ERR_NOUNIT, ERR_NOMEDIA,
+	If any error is raised the other return values are undefined
 ;     B: DEVICE ATTRIBUTES, as reported by DIODEVICE
 ;     C: MEDIAID, including MID_HDNEW if hd1k partition is found
 ;     DEHL: LBAOFFSET, of Slice if valid, 0 otherwise.
@@ -5250,11 +5252,11 @@ SYS_GETDIOFN:
 DIOMED_SLICE	.DB	0		; SLICE ARGUMENT (E)
 DIOMED_UNIT	.DB	0		; UNIT ARGUMENT  (D)
 DIOMED_DEVATT	.DB	0		; DEVICE ATTRIBUTES
+DIOMED_MID	.DB	0		; DISCOVERED MEDIAID
 ;
 DIOMED_WRKSTA	.EQU	$
 DIOMED_LBAOFF	.FILL 4,0		; START OF PARTITION / SLICE (SECTORS)
 DIOMED_LBASIZ	.FILL 4,0		; SIZE OF MEDIA / PARTITION (SECTORS)
-DIOMED_MID	.DB	0		; DISCOVERED MEDIAID
 DIOMED_SPS	.DW	0		; DISCOVERED SECTORS PER SLICE (16BIT)
 DIOMED_FND	.DB	0		; DID WE FIND A NON CPM PARTITION
 DIOMED_WRKSIZ	.EQU	$ - DIOMED_WRKSTA ; SIZE OF WORKING DATA
@@ -5297,9 +5299,6 @@ SYS_GETDIOMED:
 ;
 SYS_GETDIOMED1A:
 	; RETURN MEDIA ID (NOT HD) WITH SUCCESS
-	LD	A,(DIOMED_DEVATT)	; GET DEVICE ATTRIBUTES
-	LD	B,A			; ... AND RETURN IN B
-	LD	C,E			; RETURN MEDIA ID IN C
 	LD	DE,0			; LBA VALUE WILL BE ZERO
 	LD	HL,0
 	JP	SYS_GETDIOMED6A		; RETURN SUCCESS
@@ -5405,8 +5404,6 @@ SYS_GETDIOMED3B:
 ;
 SYS_GETDIOMED3C:
 	; NO PARTITION TABLE FOUND / NO CPM PARTITION FOUND -> HD512
-	LD	A, MID_HD		; HD512 MEDIA
-	LD	(DIOMED_MID), A		; STORE IT
 	LD	BC, SPS_HD512		; WITH HD512 SECTORS PER SLICE
 	LD	(DIOMED_SPS), BC	; STORE IT