v2.1.0: post-RC1 fixes (#61)

- Fix: broken RAM disk (introduced in RC1).
- Fix: disk errors for old MSX-DOS 1 file functions in BASIC crash the computer (#59).
- Add: new flag returned by LUN_INFO allows to instruct Nextor to ignore devices when searching devices for automatic device to drive mapping (#54).
- Fix: files can't have 3 or 4 in their names in DOS 1 mode (#55).
- Fix: after booting directly yo BASIC by pressing 3, CALL SYSTEM doesn't work.
- Fix: slot disable keys don't work on real MSX computers (#49).
- Add: new boot key, pressing N at boot time disables all the Nextor kernels present.
- Add: default DPB gets a fixed address of 7BAAh in banks 0 and 3, so it can be customized reliably.
- Add: PROMPT routine made available to drivers at address 41E8h (#42).
- Fix: the DOS 1 variables "data buffer changed" and "redirect console output to printer" were not zeroed when switching to DOS 1 mode at boot time.
- Fix: can't change volume name when there are long filename entries in the root directory (#57).
- Fix: absolute sector read/write functions not working properly when a file is mounted to a drive (#43).
- Fix: bad sector buffer management when writing to a mounted file causing data corruption on the mounted file (#58).
- Fix: drive parameters not updated on first access to a drive after a media change if the driver provides drive mapping via DRV_CONFIG, causing bad data read (#45).

Author: Konamiman

Diff for: docs/DRIVER.ASM

@@ -663,6 +663,8 @@ DEV_STATUS:
 ;               be write protected or write enabled is not considered
 ;               to be read-only.
 ;        bit 2: 1 if the LUN is a floppy disk drive.
+;        bit 3: 1 if this LUN shouldn't be used for automapping.
+;        bits 4-7: must be zero.
 ;+8 (2): Number of cylinders
 ;+10 (1): Number of heads
 ;+11 (1): Number of sectors per track

Diff for: docs/Nextor 2.1 Driver Development Guide.md

@@ -42,6 +42,8 @@
 
 [4.2.8. CHGBNK (7FD0h)](#428-chgbnk-7fd0h)
 
+[4.2.9 PROMPT (41E8h)](#429-prompt-41e8h)
+
 [4.3. The driver header](#43-the-driver-header)
 
 [4.3.1. DRV_SIGN (4100h)](#431-drv_sign-4100h)
@@ -102,9 +104,11 @@
 
 [5. Change history](#5-change-history)
 
-[5.1. v2.1.0 beta 2](#51-v210-beta-2)
+[5.1. v2.1.0 final](#51-v210-final)
+
+[5.2. v2.1.0 beta 2](#52-v210-beta-2)
 
-[5.2. v2.1.0 beta 1](#52-v210-beta-1)
+[5.3. v2.1.0 beta 1](#53-v210-beta-1)
 
 
 ## 1. Introduction
@@ -490,6 +494,25 @@ Output:    -
 Corrupts:  AF
 ```
 
+#### 4.2.9 PROMPT (41E8h)
+
+Starting with Nextor kernel 2.1.0 you can call the PROMPT routine to display a "Insert disk for drive X: and strike a key when ready" message and wait for the user to press a key. This routine is available at address 41E8h in the main bank, and you can invoke it using [CALLB0](#423-callb0-403fh) as follows:
+
+```
+PROMPT:   equ 41E8h
+CODE_ADD: equ 0F1D0h
+CALLB0:   equ 403Fh
+
+    ld hl,PROMPT
+    ld (CODE_ADD),hl
+    call CALLB0
+```
+
+The following work area is used by this routine:
+
+* The zero-based drive number is taken from TARGET, at address F33Fh.
+* The H.PROMPT hook at address F24Fh is called with the zero-based drive number in A before the routine is executed.
+
 ### 4.3. The driver header
 
 The driver header is the first part of a Nextor driver. It contains some information that helps Nextor to identify the driver and determine its type.
@@ -613,7 +636,7 @@ Please note also the following:
 
 #### 4.4.4. DRV_BASSTAT (4139h)
 
-This is the entry for the BASIC extended statements ("CALLs") handler. It works the same way as the standard handlers (see [MSX2 Technical Handbook, chapter 2](https://github.com/Konamiman/MSX2-Technical-Handbook/blob/master/md/Chapter2.md), for details), except that if the handled statements have parameters, the MSX BIOS routine CALBAS (needed to invoke the MSX BASIC interpreter helper routines) can't be used directly; instead, it must be invoked via [the CALLB0 entry](#423-callb0-403fh) in kernel page 0.
+This is the entry for the BASIC extended statements ("CALLs") handler. It works the same way as the standard handlers (see [MSX2 Technical Handbook, chapter 2, "Expansion of CMD command"](https://github.com/Konamiman/MSX2-Technical-Handbook/blob/master/md/Chapter2.md), and [MSX2 Technical Handbook, chapter 5, "Developing Cartridge Software"](https://github.com/Konamiman/MSX2-Technical-Handbook/blob/master/md/Chapter5.md) for details), except that if the handled statements have parameters, the MSX BIOS routine CALBAS (needed to invoke the MSX BASIC interpreter helper routines) can't be used directly; instead, it must be invoked via [the CALLB0 entry](#423-callb0-403fh) in kernel page 0.
 
 If the driver does not handle BASIC extended statements, it must simply set the carry flag and return.
 
@@ -977,7 +1000,8 @@ The information to be returned is a 12 byte block with the following structure:
         bit 0: 1 if the medium is removable
         bit 1: 1 if the medium is read only
         bit 2: 1 if the logical unit is a floppy disk drive
-        bits 3-7: Unused, must be zero
+        bit 3: 1 if the logical unit should not be used for automapping
+        bits 4-7: Unused, must be zero
 +8 (2): Number of cylinders
 +10 (1): Number of heads
 +11 (1): Number of sectors per track
@@ -1020,12 +1044,18 @@ This section contains the change history for the different versions of Nextor. O
 
 This list contains the changes for the 2.1 branch only. For the change history of the 2.0 branch see the _[Nextor 2.0 Driver Development Guide](../../../blob/v2.0/docs/Nextor%202.0%20Driver%20Development%20Guide.md#5-change-history)_ document.
 
-### 5.1. v2.1.0 beta 2
+### 5.1. v2.1.0 final
+
+- [LUN_INFO](#464-lun_info-4169h) can now return a flag indicating that the device/LUN should not be used for automapping.
+
+- Added the [PROMPT](#429-prompt-41e8h) routine.
+
+### 5.2. v2.1.0 beta 2
 
 - **BREAKING CHANGE:** The address of CODE_ADD, used by [the CALLB0 routine](#423-callb0-403fh), has changed to F1D0h (it was F84Ch).
 
 - Fix: there was Nextor kernel code in the 1K free area in pages 0 and 3, so putting anything here caused problems, e.g. DOS 1 mode didn't work.
 
-### 5.2. v2.1.0 beta 1
+### 5.3. v2.1.0 beta 1
 
 Added the "User is requesting reduced drive count" flag to the input of [the DRV_INIT routine](#443-drv_init-4136h) and [the DRV_CONFIG routine](#448-drv_config-4151h). 

Diff for: docs/Nextor 2.1 User Manual.md

@@ -265,7 +265,9 @@ The boot time configuration of Nextor can be modified by keeping pressed some sp
 
 *  **SHIFT**: Prevent MSX-DOS kernels from booting, but allow Nextor kernels to boot normally. This is useful to disable the internal floppy disk drive in order to get some extra TPA memory, especially in MSX-DOS 1 mode.
 
-*  **slot key**: Prevent the Nextor kernel associated to the specified slot key from booting. This is useful when the kernel ROM must be updated so you need to disable it. The associated keys for each slot are:
+* **N**: Prevent any Nextor kernel present from booting. This is useful when the kernel ROM must be updated from an storage device controlled by a non-Nextor controller (e.g. the internal floppy disk drive).
+
+*  **slot key**: Prevent the Nextor kernel associated to the specified slot key from booting. This is useful when the kernel ROM must be updated from a device controlled by another Nextor controller. The associated keys for each slot are:
 
     * Q for primary slot 1
     * A for primary slot 2
@@ -402,9 +404,10 @@ The internal disk drive would not have any drives attached if you pressed SHIFT
 
 After all drives have been assigned to drivers, a device and partition to drive automatic mapping procedure will be run for each of these drives. Each drive is mapped to the first partition found that meets the following conditions:
 
-1. Is a valid FAT12 or FAT16 partition (only FAT12 when booting in MSX-DOS 1 mode)
-2. Has the "active" flag set in the partition table (this can be set using [FDISK](#35-the-built-in-partitioning-tool))
-3. No drives have been already mapped to partitions in the same device
+1. The device doesn't have the "don't use for automapping" flag set (this flag is set by the driver)
+2. Is a valid FAT12 or FAT16 partition (only FAT12 when booting in MSX-DOS 1 mode)
+3. Has the "active" flag set in the partition table (this can be set using [FDISK](#35-the-built-in-partitioning-tool))
+4. No drives have been already mapped to partitions in the same device
 
 If no partitions are found that meet all three conditions, then the search is started over, but this time skipping the "active" flag check. If this fails again, absolute sector 0 of the device is checked (to see if the device doesn't have partitions but holds a valid FAT filesystem) as a last resort before leaving the drive unmapped.
 
@@ -648,11 +651,13 @@ Note: do not use this tool with NEXTOR.SYS versions older than 2.0 beta 2.
 The NEXBOOT.COM tool allows to easily configure the keys to be used as [one-time boot keys](#292-one-time-boot-keys) in the next reset. The syntax is:
 
 ```
-NEXBOOT <boot keys>|. [<slot> [<slot>... ]]
+NEXBOOT <boot keys>|. [*|<slot> [<slot>... ]]
 ```
 
 where the boot keys are the numeric keys, C for CTRL and S for shift, and `<slot>` are the slot numbers of the Nextor kernels to be disabled. For example `NEXBOOT 1C` will invert CTRL and 1 keys, `NEXBOOT S 1 23` will invert the SHIFT keys and disable the Nextor kernels in slots 1 and 2-3, and `NEXBOOT . 2` will just disable the Nextor kernel in slot 2.
 
+When using version 1.1 or newer of NEXBOOT.COM you can also specify `*` to disable all the Nextor kernels, this is equivalent to pressing `N` while booting. Note however that this will only with Nextor kernels whose version is 2.1 or newer.
+
 In all cases, the tool resets the computer immediately after apporpriately setting the keys information in RAM.
 
 #### 3.4.12. EMUFILE: the disk emulation mode tool

Diff for: source/kernel/bank0/bdos.mac

@@ -52,6 +52,7 @@ endif
 ;-----------------------------------------------------------------------------
 ;
 KAB_ROUTINE:
+KABR::
 ;
 ;    This  is the KBDOS abort routine which is set up whenever the 0F37Dh BDOS
 ; entry is active.  It is set up by  the  "KB_INIT"  routine  above  and  will
@@ -60,6 +61,9 @@ KAB_ROUTINE:
 ; the  first  BDOS  call,  switches  back to the user's stack and jumps to the
 ; user's defined "BREAKVECT" routine.
 ;
+; The hook at KAB_VECT is set to an intermediate hook KABJ instead of pointing
+; directly here, see KABJ at the end of drv.mac for an explanation of why.
+;
 ;
 		exx				;Save error code in B'
 		ld	b,a			; just for fun to BUFOUT.
@@ -73,6 +77,7 @@ KAB_ROUTINE:
 ;-----------------------------------------------------------------------------
 ;
 KDSK_ROUTINE:
+KDERR::
 ;
 ;    This is the KBDOS disk error routine which is set up whenever the  0F37Dh
 ; BDOS  entry is active.  It is set up by the "KB_INIT" routine above and will
@@ -82,6 +87,9 @@ KDSK_ROUTINE:
 ; routine  returns then the KBDOS paging is re-enabled and control returned to
 ; the KBDOS.
 ;
+; The hook at KDSK_VECT is set to an intermediate hook KDERJ instead of pointing
+; directly here, see KDERJ at the end of drv.mac for an explanation of why.
+;
 ; Entry:    A' = Old error code (passed to DISKVECT in C)
 ;	    A  = New error code (passed to DISKVECT in A')
 ;	    B  = Drive number (decremented & passed to DISKVECT in A)
@@ -195,9 +203,14 @@ if 1
 ; Insure error vectors are directed to us.  Just for bad mannered applications
 ; that call 0005h at one time and F37Dh at another time.  ...HF...
 ;
-		ld	hl,KAB_ROUTINE		;Setup the disk vector and
+; Note: KABJ and KDERJ need to be defined at the same address as defined at drv.mac
+
+KABJ    equ 7BC0h
+KDERJ   equ KABJ+7
+
+		ld	hl,KABJ		;		;Setup the disk vector and
 		ld	(KAB_VECT##),hl		; abort vector routines for
-		ld	hl,KDSK_ROUTINE		; MSX-DOS 1.0 compatability.
+		ld	hl,KDERJ	;		; MSX-DOS 1.0 compatability.
 		ld	(KDSK_VECT##),hl	;
 endif
 		LD	HL,(BDOS_STACK##)

Diff for: source/kernel/bank0/dskab.mac

@@ -0,0 +1,21 @@
+    .z80
+
+    INCLUDE	MACROS.INC
+	INCLUDE	CONST.INC
+    
+    ;org 7FC0h
+
+    nop
+    nop
+    nop
+    nop
+    jp KABR##
+
+    nop
+    nop
+    nop
+    nop
+    jp KDSKR##
+
+    finish	<DSKAB>
+	end