v2.1 beta 2

- Nextor will now try to load MSXDOS2.SYS if NEXTOR.SYS is not found in the boot drive.

- The method for selecting partitions for automatic mapping has changed from requiring a NEXTOR.DAT file in the root directory to having the "active" flag set in the partition table.

- Now the first 9 partitions of a device will be scanned during the automatic mapping procedure, this includes extended partitions.

- FDISK allows to change the "active" flag of new and existing partitions.

- FDISK now always creates extended partitions, even if 4 or less partitions are defined.

- FDISK now creates FAT16 partitions with a partition type code of 14 (FAT16 LBA) instead of 6 (FAT16 CHS).

- The numeric keyboard can now be used both when booting and when changing disks in disk emulation mode.

- Russian keyboard is now properly recognized (numeric keys only).

- Introduced the boot key inverters.

- Introduced the one-time boot keys.

- Introduced the NEXBOOT.COM tool to set the RAM based one-time boot keys.

- Introduced the RAM based one-time disk emulation mode.

- The method to enter the old disk emulation mode (now named "persistent") has changed from requiring a NEXT_DSK.DAT file in the root directory to storing a pointer to the emulation data file in the partition table of the device.

- Pressing the 0 key at boot time will delete the pointer to the emulation data file in the partition table, thus permanently disabling the emulation mode - no need to manually do anything else.

- When Nextor is waiting for a disk key press after having pressed GRAPH in disk emulation mode, now you can press GRAPH again to cancel the disk change.

- The first Nextor kernel to boot now clears the screen before invoking the driver initialization.

- ARG is no longer used as temporary work area by the Nextor kernel, this should improve the compatibility of games in disk emulation mode.

- Fix: drive was remapped in case of error (even if it was retried successfully).

- Fix: boot sector checksum calculation had a bug that caused "Wrong disk" errors.

- Fix: #1 pressing CTRL+STOP while Nextor was trying to load NEXTOR.SYS hanged the computer.

- Fix: #23 computer hanged when booting with one single drive letter (e.g. when using single-device controller in a computer without internal disk drive).

- Fix: #29 wrong stack management hangedd the computer when a file handle was read or written to a number of times.

- Fix: computer crashing when more than one Nextor kernel was present as soon as the extended BIOS hook was called (for example, when loading COMMAND2.COM).

- BREAKING CHANGE: The address of CODE_ADD, used by the CALLB0 routine, 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.

- _GPART now returns the status byte of the partition, and allows to retrieve the device sector number that holds the partition table entry instead of information about the partition.

Author: Konamiman

.gitignore

@@ -1,6 +1,7 @@
 syntax: glob
 
 .vs/
+.vscode/
 bin/**
 *.sym
 *.SYM

docs/DRIVER.ASM

@@ -1,4 +1,4 @@
-    ; Dummy disk driver for Nextor 2.0
+    ; Dummy disk driver for Nextor 2.1
     ; By Konamiman, 8/2018
     ;
     ; This code can be used as the basis for developing
@@ -21,7 +21,7 @@ DRV_START:
 ;This is a 2 byte buffer to store the address of code to be executed.
 ;It is used by some of the kernel page 0 routines.
 
-CODE_ADD:	equ	0F84Ch
+CODE_ADD:	equ	0F1D0h
 
 
 ;-----------------------------------------------------------------------------

docs/Nextor 2.1 Driver Development Guide.md

@@ -102,7 +102,9 @@
 
 [5. Change history](#5-change-history)
 
-[5.1. v2.1.0 beta 1](#51-v210-beta-1)
+[5.1. v2.1.0 beta 2](#51-v210-beta-2)
+
+[5.2. v2.1.0 beta 1](#52-v210-beta-1)
 
 
 ## 1. Introduction
@@ -428,7 +430,7 @@ Input:  Address of code to invoke in (CODE_ADD).
 Output: AF, BC, DE, HL, IX, IY returned from the called routine.
 ```
 
-Note: the address of CODE_ADD is F84Ch.
+Note: the address of CODE_ADD is F1D0h.
 
  #### 4.2.4. CALBNK (4042h)
 
@@ -611,13 +613,13 @@ 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, 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 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](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.
 
 If the driver does not handle BASIC extended statements, it must simply set the carry flag and return.
 
 #### 4.4.5. DRV_BASDEV (413Ch)
 
-This is the entry for the BASIC extended devices handler. It works the same way as the standard handlers (see _MSX2 Technical Handbook_, chapter 2, for details), but see the note on DRV_BASSTAT about CALBAS.
+This is the entry for the BASIC extended devices 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), but see the note about CALBAS on [DRV_BASSTAT](#444-drv_basstat-4139h).
 
 If the driver does not handle BASIC extended devices, it must simply set the carry flag and return.
 
@@ -1018,6 +1020,12 @@ 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 beta 1
+### 5.1. 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
 
 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).