Nextor 2.0 User Manual
Contents
1. R 1 130 PRINT DE amp H HEXS R 2 140 PRINT HL amp H HEXS R 3 150 PRINT IX amp H HEXS R 4 160 PRINT TY amp H HEXS R 5 23 3 7 New BASIC error codes The following new BASIC error codes are defined to handle the possible errors of the new BASIC commands These errors are available in MSX DOS 1 mode as well for the commands that work in this environment The numbers in parenthesis are the error codes e Invalid device driver 76 This error will be thrown by the CALL MAPDRV command in any of these events o The specified slot number does not contain a Nextor device based driver o No slot number is specified but the drive is not currently mapped to a Nextor device based driver o InMSX DOS 1 mode the drive was not originally mapped to a Nextor device based driver or was mapped to a different driver e Invalid device or LUN 77 This error will be thrown by the CALL MAPDRV command in any of these events o The device and or LUN with the specified index is not available on the specified or implicit driver o The device and or LUN with the specified index exists on the specified or implicit driver but it is not a block device e Invalid partition number 78 This error will be thrown by the CALL MAPDRV command if the specified partition does not exist on the specified or implicit device e Partition already in use 79 This error2. information that depends on the associated driver type driver name and version for Nextor drivers device and logical unit numbers for Nextor device based drivers relative unit for MSX DOS and Nextor drive based drivers MSX DOS drivers are identified as Legacy driver 3 4 5 LOCK the drive lock and unlock tool The LOCK COM utility allows locking and unlocking drive letters The usage syntax for LOCK is LOCK lt drive letter gt ON OFF When ran without parameters a list of the drive letters currently locked is shown If only a drive letters is specified the current lock status for the drive is shown When a drive is marked as locked Nextor will never check the media change status for the drive instead the inserted media is assumed to never change This speeds up media access but be careful since data corruption may happen if the media is changed while it is locked Any disk error which is aborted will automatically unlock the involved drive other than that drives will be unlocked only when the LOCK utility is ran with the OFF parameter Nextor will never automatically lock a drive 3 4 6 RALLOC the reduced zero allocation information mode tool The RALLOC COM utility allows activating or deactivating the reduced allocation information mode for a drive The usage syntax for RALLOC is RALLOC lt drive letter gt ON OFF If no parameters are specified a list of drives currently in reduced allocation information m
3. thus undoing the feature introduced in v2 0 3 of filling it only on Japanese computers Users of computers with the corrupted error messages problem should use the ERRLANG environment variable see 4 2 English error messages in kanji mode e NEXTOR SYS fixed it was displaying garbage instead of the proper error messages in kanji mode e Two variants of NEXTOR SYS are offered now with and without Japanese error messages see 4 3 Reduced NEXTOR SYS without Japanese error messages 5 2 V2 0 3 e The code that calculates the free space on a FAT16 volume used by the ALLOC and DSPACE function calls has been rewritten from scratch for performance Now calculating the free space ona FAT16 volume takes about 1 10 of the time it took in previous versions e The code that decides the FAT type of a volume based on the cluster count has been modified In previous versions a volume with a cluster count of 4095 or less was always considered to be holding a FAT 12 filesystem Now a volume with a cluster count between 4085 and 4095 is considered to hold a FAT 12 filesystem unless the boot sector contains the string FAT16 at position 36 e The maximum cluster count for partitions generated by FDISK has been corrected from 4085 to 4084 in the case of FAT12 partitions and from 65526 to 65524 in the case of FAT16 partitions e The zero allocation information mode has been added see 2 5 Reduced and zero allocation information mode and 3 4 6 RALLOC
4. 2 the NEXTOR SYS version number returned by the DOSVER function call is stored in RAM and can be changed easily see the Nextor 2 0 Programmers Reference for more details A command line tool that allows to easily do this change has been created as well its name is NSYSVER COM and can be used as follows NSYSVER lt major version number gt lt secondary version number gt For example NSYSVER 2 20 Note that this will change only the value of the NEXTOR SYS version number returned by the DOSVER function call the VER command will still display the real file version number Note the version number change performed by this tool is temporary and it will cease to have effect that is the NEXTOR SYS version number will revert to its real value when NEXTOR SYS is reloaded either because the BASIC prompt is entered and exited via CALL SYSTEM or because the computer is rebooted Note do not use this tool with NEXTOR SYS versions older than 2 0 beta 2 16 3 5 The built in partitioning tool The Nextor kernel has an embedded utility for partitioning storage devices attached to Nextor device based drivers To start it just invoke CALL FDISK from the BASIC prompt It works properly on both 40 columns and 80 columns mode Please note that starting the FDISK tool will delete the current BASIC program from memory The tool has a user interface based on menus so anyone should be able to use it by just following the indications provided in t
5. eee 26 Bsa et ocean erage ge cee ee ee 27 BA V2 0 EE A eect eee nen aie we etestioe 27 5 5 V2 0NA ener mene eee mene a ne ae eee eee re ee ee 27 B02 Os sates atta dss gece sce cece see ea eaes eae pane ee eeeseee 27 By 7 We OG el cree cceicelen ce steeoercaded eaten eaten ook meiesdah soot aie eee eee 27 5 8 V2 0Alpha 2p eee ene eee ee ee ee er een Terre eee ee re rere ee te ee a 28 5 9 VFO 2 reni eee ere 5 em cane xe ued a alee Shea td netted aba RR E 28 MOI IC I ojressedoceasairnaeptiee De A a a a bande a a a a a a 29 1 Introduction Nextor is an enhanced version of MSX DOS 2 the disk operating system for MSX computers It is based on MSX DOS 2 31 with which it is 100 compatible This document provides a description of the features that Nextor adds to MSX DOS 2 and is intended primarily for end users but it explains basic concepts that will be useful for developers as well There are however two other documents aimed specifically at developers Nextor 2 0 Programmers Reference and Nextor 2 0 Driver Development Guide The reader of this document is assumed to have experience with MSX DOS 2 at least at the user level 1 1 Background MSX DOS is the only official disk operating system for MSX computers The last version labeled 2 31 appeared in 1990 accompanying MSX Turbo R computers MSX DOS was developed in a time in which the only option for massive storage in MSX computers was the floppy disk and when used as a floppy disk only
6. every character of the string 15 When the fast STROUT mode is active the string will be copied to a 512 byte buffer in page 3 and then it will be printed in one single call to the kernel code which increases the speed of the printing process The drawback is that the string length is limited to 511 bytes when this mode is active longer strings will be truncated only the first 511 characters will be displayed 3 4 9 DELALL the partition quick format tool The DELALL COM utility will perform a quick format on the filesystem visible on a given drive letter The usage syntax for DELALL is DELALL lt drive letter gt What this tool does is to clean the FAT and root directory areas of the filesystem thus effectively deleting all the information on the filesystem There is no way to undo the operation the files will be permanently lost so please use with care This tool can be used on any drive even those attached to MSX DOS drivers Note that the drive must be mapped to a valid FAT 12 or FAT 16 filesystem otherwise this tool will not work 3 4 10 NSYSVER the NEXTOR SYS version changer Some MSX DOS command line applications are known to check the version number of MSXDOS2 SYS NEXTOR SYS in the case of Nextor and refuse to work if this number is smaller than a certain value typically 2 20 This is a problem since the current NEXTOR SYS version number is 2 0 As a workaround for this issue starting at version 2 0 beta
7. in the MSX DOS 1 prompt you need the usual MSXDOS SYS and COMMAND COM files Also if you have just the kernel and no NEXTOR SYS or MSXDOS SYS files Nextor will boot in the BASIC prompt running AUTOEXEC BAS if present Therefore in order to install Nextor you have two options 1 Burn a ROM with the appropriate Nextor driver directly in the storage device controller 2 Burn a standalone version in a flash ROM cartridge and use it together with your storage device controller in another slot Also you need to copy at least NEXTOR SYS and COMMAND2 COM to your boot device it is recommended to have the associated utilities available as well unless you are happy in the BASIC prompt More details about the boot procedure follow 3 1 1 Note for Sunrise IDE CF users If you want to burn the Nextor kernel ROM in a Sunrise IDE cartridge or in a Sunrise CF reader cartridge you can t use the IDEFLOAD COM program because it assumes that the file to be burned has a size of 64K but the Nextor kernel is bigger 128K including the driver in current version Instead you should use IDEFL128 COM a modified version of the program that burns 128K files This program is available at Konamiman s web page as well See Section 5 Also note that the Sunrise IDE driver supplied with Nextor 2 0 is an experimental driver that has some limitations more precisely e Only LBA mode block devices are supported there is no support for CHS or ATAPI de
8. is assumed to be the same of the device which contains the partition already mapped to the drive if the drive is not currently mapped to a device based driver an Invalid device driver error will be thrown e CALL MAPDRV lt drive gt lt partition gt Maps the specified drive to the specified partition The device is assumed to be the same one that contains the partition already mapped to the drive if the drive is not currently mapped to a device based driver an Invalid device driver error will be thrown e CALL MAPDRV lt drive gt 1 Leaves the specified drive unmapped Further attempts to access the drive will throw a Bad drive name error Disk I O error in MSX DOS 1 mode e CALL MAPDRV lt drive gt 2 e CALL MAPDRV lt drive gt Maps the specified drive to its default value If at boot time the drive was unmapped or was mapped to a MSX DOS driver or to a Nextor drive based driver then the drive will be reverted to its original mapping state Otherwise and automatic mapping procedure will be performed the procedure is equal to the one performed at boot time except that the NEXTOR DAT file will not be searched see Section 3 2 for more details this may result or not on the drive having the same mapping it had at boot time depending on which devices are available and how the other drives are mapped 21 The command parameters syntax is as follows e lt drive gt is a string
9. operating system MSX DOS works indeed just fine Over the years however more modern massive storage options have appeared in the form of amateur made hardware from the early 90 s SCSI and IDE hard disk controllers to today s multimedia card readers MSX DOS has been used to manage these devices but not without some problems e MSX DOS handles sector numbers as 16 bit entities and the only filesystem it supports is FAT12 This limits the size of a single filesystem volume to 32MB Unofficial patches have been developed to add support for the FAT 16 filesystem e The actual device driver the code that interacts with the massive storage controller hardware is embedded within the operating system kernel ROM present in computers with built in floppy disk drives and in external floppy disk controllers There is no officially documented way to embed a custom device driver within the kernel ROM developers of custom storage controller hardware have to reverse engineer the kernel code in order to embed a custom driver e There is a fixed direct one to one correspondence between the drive letters as seen by the user and the device units exposed by the device driver API For example in order to access drive A MSX DOS asks the driver to access its first device while the second device is queried when accessing drive B This is OK for floppy disks but when using more complex devices that have one or more partitions it is up to the driver an
10. please refer to the Nextor 2 0 Programmers Reference document Please note that none of these tools work in MSX DOS 1 mode However there are equivalent BASIC CALL commands that provide equivalent functionality for most of the tools Some of the tools admit a lt driver slot gt parameter In all of these number 0 may be specified instead of a slot number with the meaning of the primary controller 3 4 1 MAPDRV the drive mapping tool MAPDRV COM is a tool that allows mapping a drive letter to a partition on a device controlled by a Nextor device based driver It is possible to map any drive even those initially unmapped or associated to a MSX DOS driver or a Nextor drive based driver The usage syntax for MAPDRV is MAPDRV L lt drive gt lt partition gt d u lt device index gt lt LUN index gt lt driver slot gt lt driver subslot gt 12 Partition number 1 refers to the first primary partition on the device Partitions 2 to 4 refer to extended partitions 2 1 to 2 4 if partition 2 of the device is extended otherwise they refer to primary partitions 2 to 4 Partitions 5 onwards always refer to the extended partition 2 P 1 If partition number 0 is specified then the drive is mapped to the absolute sector zero of the device There are three options for specifying the device where the partition is located e Do not supply any parameter after the partition number In this case the partition is assumed to
11. the recipe for embedding the driver within the Nextor kernel are provided so that no more reverse engineering is needed The driver main purpose is to enumerate and access storage devices but it also contains some extensibility points to add custom BASIC statements via CALL command extended BIOS commands or a timer interrupt service routine The following resources are available for Nextor device driver developers e The Nextor 2 0 Driver Development Guide document e A template driver file DRIVER ASM that can be used as the skeleton for developing custom drivers e Acommand line utility MKNXEROM that will do all the work of embedding a device driver within the Nextor kernel ROM It is provided as a Windows executable MKNEXROM EXE and as a standard C source file MKNEXROM C Note at this time it is not possible to invoke the FORMAT command on a drive mapped to a device controlled by a Nextor device based driver This will change in a future version of Nextor 2 3 Drive to device partition mapping management Driver developers can choose between two driver styles when developing a Nextor device driver the drive based driver and the device based driver The former mimics the MSX DOS drivers by providing a one to one mapping between OS drive letters and driver units it is still the responsibility of the driver to manage the drive to device and partition mapping The latter is way more interesting Device based drivers do no
12. variants are offered since NEXTOR SYS version 2 01 released together with kernel version 2 0 4 Note that version 2 00 was already reduced but had a bug that caused garbage to be displayed instead of the proper error messages in kanji mode Note that error messages will be displayed in English regardless of the variant used if the ERRLANG environment item exists with value EN see 4 2 English error messages in kanji mode 25 5 Change history This section contains the change history for the different versions of Nextor Changes that affect application or driver development are not listed here instead you should look at the Nextor 2 0 Programmers Reference and Nextor 2 0 Driver Development Guide documents for a list of changes of that type 5 1 v2 0 4 e Fixed a bug introduced in v2 0 3 that caused the free disk space to be reported incorrectly by one cluster e Fixed a bug that caused File already in use errors when copying files within the same drive e Fixed a bug that caused the computer to crash when copying files from to a floppy disk drive in DOS 1 mode e Fixed a bug that caused the computer to crash when activating the kanji mode CALL KANJI from BASIC e Introduced the ERRLANG environment item for displaying error messages in English when in kanji mode see 4 2 English error messages in kanji mode e The system variable KANJTABLE at amp HF30F now is always filled regardless of the computer s character set
13. 1 mode The CHDRV MAPDRV and _LOCKDRV commands can now use a number to specify the drive O default drive 1 A etc The computer boots with load assigned to the F7 key even in MSX1 and MSX2 The drive from which NEXTOR SYS is loaded is no more automatically locked All the Nextor new CALL commands show help when ran without parameters The order and of the parameters for the MAPDRV COM has been changed to be the same as the _ MAPDRV command Fixed a bug in the DEVINFO COM tool the device manufacturer and name were shown swapped Command line tools now show a short usage information when invoked without parameters FDISK allows now to create partitions up to 4GB FDISK default partition size is now 16M instead of device capacity in DOS 1 mode FDISK now shows warning only partitions of 16M or less can be used in DOS 1 mode in DOS 1 mode FDISK now shows please reset message after partitioning The DEVINFO COM tool now shows the device size in MB if the size is under 10GB or in KB if the size is under 10MB Added the boot sector checksum feature for drivers that report a device change status of not sure Devices are now reported as being fixed in the experimental Sunrise IDE driver hot card swapping is not supported when CF cards 5 8 v2 0 Alpha 2b Previous versions assumed that ROM bank 0 was switched at boot time and the system crashed if any other bank was switched instead Now Nextor boots properly regardless of wh
14. 2M for FAT12 partitions 64M 128M 256M 512M 1G 2G or 4G for FAT 16 partitions If this is not possible it is better to select the partition size as slightly smaller than the closest power of two than slightly higher that is for example 31M is better than 33M Remember that Nextor can handle devices with FAT16 partitions and standard boot sectors if you use a factory partitioned device of 2GB or less you probably don t need to partition it unless you want to create MSX DOS 1 compatible partitions 4GB devices are usually shipped with a FAT32 partition so you will need to partition it with FDISK anyway The partitioning tool works in MSX DOS 1 mode too Note however that the tool will always allow you to create partitions larger than 16M which are not compatible with MSX DOS 1 17 3 6 Extensions to Disk BASIC Nextor adds some new commands to Disk BASIC mainly to ease the management of devices and partitions from this environment Also some of the commands that already existed in MSX DOS have been extended or improved Some of the new CALL commands take parameters These commands can be run without parameters in order to get help on how to use them Unless otherwise stated the Nextor modifications of existing Disk BASIC are not available in MSX DOS 1 mode but the new commands are 3 6 1 The DSKF command The DSKF command which tells the free space available on a drive returns a free cluster count in MSX DOS In Nextor
15. Also some of the existing commands have been improved See 3 6 Extensions to Disk BASIC 3 Using N XtO cceeeeeeeee eee eeeeettneee teeter ee eeeenaaeeeeeeeeeeneeee 7 3 1 Installing 2 6 rinn ee ere eee ee eee ee ee eee eee rer ee ree eres 8 3 2 BOGNA NEXON eee ee een em e A E eee eee reer eer ree ree ee ee ee 9 3 38 Managing media CHANGES xis scsasosaicosneta nerd sadsncseaeiubendseis EE cada EE AEE SEA N ENBEI EEA AANER 11 3 4 The command line tools seedce coass sec scceebee soars earcaletea seals uiasdareteesaceksia nd outee Gaede eager aula aes 12 3 5 The built in partitioning Ta tc cia esis et eee ccneatec eterna eles ee ean needle tatnnaeee ee cedunentacuentieiaies 17 3 6 Extensions to DISK BASIC nreccicvsrcrenus srareterecctinarsSteimiud niatenst beaanterentendnorenenetensiene bareteieceiendsSnetetetmatenlie 18 3 7 New BASIC error codes xcicccpcpeccicicceteniernrerelcatneisineis Mnsinwieieenmis tae ieee ten einem 24 4 Other iMproye meris teeta costes ae oe eee eee eee ae 25 ra R oTe Co a To FP cheno E E A ene ee ieee eens 25 4 2 English error messages in kanji mode scciscsiascsecicsrcesesiieiasemiesaristensec enim 25 4 3 Reduced NEXTOR SYS without Japanese error messages eseessssresrrrrersstrrrrrrnrrrssrrrrrrnrereet 25 5 Change NIStOry aercrenanen a E T 26 Sd V2 ates cae ead ects ee aaesten eats ease eee aes eni eee ies ee eeeeeeeenes 26 52 V2 0 ES eee ee ee eae ne ee ere ee ee ere eee ee ee ere ee ee ee eer en
16. DEVINFO COM Z80MODE COM MAPDRV COM and the CALL MAPDRV command now admit 0 instead of a slot number with the meaning of the primary controller see 3 4 The command line tools and 3 6 9 The CALL MAPDRV command e Added the NSYSVER tool see 3 4 10 NSYSVER the NEXTOR SYS version changer 5 7 v2 0 Beta 1 e Fixed a bug that caused device sectors to be read more times than necessary thus seriously hurting device access speed e Fixed a bug that caused the computer crash on the first drive access after the mapped device had changed e Fixed a bug that caused the computer to freeze at boot time when using an unpartitioned device e Fixed a bug that could prevent booting when the Nextor kernel ROM was built using the ASCII8 mapper e Fixed a bug in the LOCKDRV command it was changing lock status when it should only check it e Fixed a bug that crashed the computer when using the FCB related function calls to access the RAM disk e Fixed a bug on the drive number handling in DSKI and DSKO e Fixed a bug that caused the internal RAM mapper to be configured as the primary mapper on all MSX models not only on Turbo R e DSKI and DSKO now admit 32 bit sector numbers 27 Fixed a bug that caused function call_GDRVR to fail when called via the F37Dh hook Added the CCURDRV command Added the _DRVINFO command Added the DRIVERS command Added the NEXTOR command Added the USR command The _CHDRV command now works in DOS
17. L commands that Nextor provides for the BASIC environment 3 6 4 The CALL CHDRV command This command changes the current drive and it exists already in MSX DOS 2 Disk BASIC However Nextor expands it in two ways e The command is now available in MSX DOS 1 mode as well e The drive number can be specified as a number instead of a drive letter from 1 being A to 8 being H So for example CHDRV 3 is the same as CHDRV C 3 6 5 The CALL CURDRV command This command will simply display the current drive 19 3 6 6 The CALL DRIVERS command This command is equivalent to the DRIVERS COM tool which displays information about the available MSX DOS and Nextor drivers It will display the name and version for Nextor drivers only the slot number and the assigned drives at boot time MSX DOS drivers will be identified as Legacy driver 3 6 7 The CALL DRVINFO command This command is equivalent to the DRVINFO COM utility which displays information about all the available drive letters those that are not unmapped The displayed information includes the associated driver slot and other information that depends on the associated driver type driver name and version for Nextor drivers device and logical unit numbers for Nextor device based drivers relative unit for MSX DOS and Nextor drive based drivers MSX DOS drivers are identified as Legacy driver 3 6 8 The CALL LOCKDRV command This command allows to lock an
18. MSX DOS 1 The Nextor kernel contains the MSX DOS 1 kernel so that it is possible to boot in this environment when necessary The Nextor version of MSX DOS 1 does not provide any additional functionality to users or developers relative to the original version however it has been modified internally so that it can access devices attached to Nextor drivers See 3 2 1 Booting in DOS 1 mode 2 12 Enhanced Disk BASIC Disk BASIC has been extended with new commands Also some of the existing commands have been improved See 3 6 Extensions to Disk BASIC 3 Using Nextor This section explains the operational details of Nextor and the associated utilities 3 1 Installing Nextor Nextor consists of the following components e The Nextor kernel ROM It must contain a device driver although a standalone version is provided which contains a dummy driver exposing no devices e The NEXTOR SYS file which is necessary in order to boot in the DOS prompt This file has the role that MSXDOS2 SYS had in MSX DOS 2 in fact NEXTOR SYS is just an extended version of MSXDOS2 SYS e The COMMAND2 COM file There is no special command interpreter for Nextor instead the same command interpreter of MSX DOS 2 is used any version of COMMAND2 COM from 2 20 will do and new features are handled by using external commands Note two variants of the NEXTOR SYS file exist See 4 3 Reduced NEXTOR SYS without Japanese error messages In order to boot
19. Nextor 2 0 User Manual By Konamiman 10 2014 Index 1 MATE EG OW cies tava scien na ven tain teen a awe wel maul ca sna tenia diiba tna ua Ue lornunts Geeaumdatnmnasioewcauaed 2 Te Background reci ea EE EE E E E decane E E E nausea 2 E oe E E E E T 3 1 3 System requirements seic2h cnet cedeselu exerci cedamesaeasretetd nade ea iauen ced tenes eae oe uaceenenee tees ee eneea keene 3 2 FP OANUNGS usisa anne a A A ntatets A E A a E E R 3 2 2 Standardized and documented driver development system ssssssssssrrrtrssserrrrrrrrrrsserrnrrrnnnnnsernnne 4 2 3 Drive to device partition mapping ManageMent cccceeeeeeeseeeeceeee eee eeteeeeeaeeeeeeeeeeetesenaaeaeeeeeeeeeeeeee 4 2 DING OCK ci austin naam a a a a a E a E a a Eaa aE aa 4 2 5 Reduced and zero allocation information MOdGC ccccceeeeeeseseceeeeeeeeeteneseaeeeeeeeeeeenenenaaaaeeeseeeeeeenea 5 2 0 Z80 ACESS MOQO oss cee ance ni denetarik EEEE AAE ven ERE EA EEEE RETE ote ETEA EUNE EAEE EEEE RTE EATE REECE EA 5 2 1 FASUSI ROUT MOE ecic owe EE E TE E E aise eine 6 2 8 Extended mapper support routines s c22 102ocitr lined aiid aGui dn eae Guisideddnisk 6 2 9 1819 21 ene Ten en ee ee a ee ee ee ee eee ee ee eee 6 210 Built in partitioning 100 sreci iere aea E A EEEE E KEE RNE 7 2 11 embedded MSX DOS 1 AAedshnntiednhenet E E E EE EA E R RA 7 2 12 Enhan ed Disk BASIC indirect nance tana rataakn daa aann nnn 7 Disk BASIC has been extended with new commands
20. ands will fail with an Overflow error This is designed this way to prevent inadvertent access to the wrong sector For example 10 DEFSNG S 20 S 12345678 30 PRINT S Prints 12345700 40 PRINT DSKIS 0 S Throws Overflow 18 The previous example will work provided that the sector exists in the device if line 10 is changed to DEFDBL s Always use double precision variables if you are going to access arbitrary sector numbers in your BASIC code An Overflow error will be thrown too if the sector number specified does not fit in 32 bits that is if it is greater than 4294967295 In order to maintain compatibility with the MSX DOS equivalent command negative sector numbers are accepted to which 65536 is added to get the real sector number but only if the sector number can be evaluated as an integer 16 bit expression Therefore the following commands are equivalent and will work if the sector exists in the device RINT DSKI 0 65535 RINT DSKI 0 amp HFFFF RINT DSKIS 0 1 EFINT S S 1 PRINT DSKI 0 S Uv yy However the following will throw a Disk I O error PRINT DSKI 0 CDBL 1 DEFDBL S S 1 PRINT DSKIS 0 S None of this apply to MSX DOS 1 mode in this mode only integer 16 bit sector numbers are accepted 3 6 3 The CALL NEXTOR command This command will simply display a list of the new CAL
21. apped or mapped to a MSX DOS driver or a Nextor drive based driver at boot time e The new mapping information may specify a different partition and or device but the driver slot must be the same that was assigned to the drive at boot time This is not an issue if there is only one Nextor kernel in the system Also please note that in MSX DOS 1 mode if you map a drive to an unsupported partition type a FAT16 partition or a FAT 12 partition having more than 3 sectors per FAT you will always get a Disk I O error when accessing that drive This does not mean that the device is actually faulty only that Nextor refuses to access it 3 6 10 The CALL MAPDRVL command The CALL MAPDRVL command is identical to the CALL MAPDRV command except that it will perform a drive lock see Sections 2 4 and 3 4 5 immediately after changing the drive mapping Note that this command is not available in MSX DOS 1 mode in which the concept of drive lock does not exist 22 3 6 11 The CALL USR command The CALL USR command allows the execution of assembler code from BASIC code It is equivalent to the standard MSX BASIC DEF USR command and the USR function but with an added feature it allows to specify the input values of the Z80 registers for the code to execute and to read the output values after the execution The syntax of the CALL USR command is as follows CALL USR lt code address gt lt registers address gt lt code addres
22. be in the same device already mapped to the drive this works only if the drive is currently mapped to a device based driver e Supply a device index but not a slot number In this case the partition is assumed to be in the specified device and the device is assumed to be controlled by the kernel on the same slot of the currently mapped device this works only if the drive is currently mapped to a device based driver e Supply a device index and a slot number In this case the slot corresponds to the Nextor kernel that contains the driver that handles the device When a device number is supplied a logical unit number can be supplied too default value for the logical unit number is 1 If d is specified instead of a partition number then the drive will be mapped to its default state which can be one of the following e lf the drive was unmapped at boot time then it is left unmapped e f at boot time the drive was assigned to a MSX DOS driver unit or to a Nextor drive based unit then it is mapped to the same unit e f at boot time the drive was assigned to a Nextor device based driver then an automatic mapping procedure equal to the one performed at boot time except that the NEXTOR DAT file is not searched will be performed This may or may not result in the drive having the same mapping it had at boot time depending on the mapping state of the other drives If u is specified instead of a partition number then
23. d unlock drives see Sections 2 4 and 3 4 5 It is used as follows e CALL LOCKDRV lt drive gt Displays the current lock status of the drive e CALL LOCKDRV lt drive gt 0 Unlocks the drive e CALL LOCKDRV lt drive gt lt any non O number gt Locks the drive lt drive gt is a string with the drive letter followed by a colon for example A or a number being 1 to 8 for drives A to H or O for the current drive This command is not available in MSX DOS 1 mode in which the concept of drive lock does not exist 20 3 6 9 The CALL MAPDRV command This command that allows changing the drive to device and partition mapping from the BASIC environment It is equivalent to the MAPDRV COM tool The CALL MAPDRYV syntax is explained below Some of the parameters are optional therefore all the possible variations are explained starting with the most complete using all parameters one Details about the possible values for each parameter are explained later e CALL MAPDRV lt drive gt lt partition gt lt device gt lt slot gt 0 Maps the specified drive to the specified partition of the specified device which is controlled by the driver on the specified slot If 0 is specified instead of a slot number the slot of the primary controller is used e CALL MAPDRV lt drive gt lt partition gt lt device gt Maps the specified drive to the specified partition of the specified device The driver slot
24. d usually also to external tools made by the driver developer to manage the drive to device and partition assignment e Managing non block devices such as CD ROMs is extremely difficult as it implies a hard work of reverse engineering on the kernel code 1 2 Goals The primary goal of Nextor is to solve the aforementioned problems by using MSX DOS 2 as the basis for implementing the features that are needed for a MSX computer equipped with 21th century storage devices More specifically the main goals that Nextor development efforts aim to are e Provide native support for the FAT16 filesystem e Provide a standardized well documented system for developing custom storage device drivers and either embedding them within the OS kernel ROM or loading them dynamically from RAM e Provide a device based driver system in contrast with the MSX DOS drive based system so that the driver developer must only worry about enumerating and accessing storage devices and it is the operating system who manages the device and partition to drive assignment e Provide support for non block devices and for block devices with filesystems other than FAT12 16 Aside from the main goals Nextor offers other secondary but also useful new features not present in MSX DOS Keep on reading for more details 1 3 System requirements Nextor will run on any MSX computer from MSX1 onwards having at least 128K of mapped memory In computers with no mapped mem
25. e BASIC prompt in MSX DOS 1 mode it is no longer necessary to execute POKE amp HF346 1 prior to CALL SYSTEM 3 3 Managing media changes Before trying to read or write data from a device MSX DOS asks the device driver if the media has changed in order to update its internal information about the accessed filesystem Nextor does the same but if the drive being accessed is mapped to a device based driver things get a little trickier because disk partitioning is involved When Nextor detects a media change in a drive mapped to a removable device based driver the following procedure is performed e The drive is mapped to the first available valid primary partition found on the device Valid partitions are FAT12 and FAT16 partitions If the device has no partition table the drive is mapped to its absolute sector zero e All the other drives mapped to other partitions of the same device will be left unmapped The device driver may also reply not sure when asked for device change status In that case the procedure is as follows e When Nextor first reads the boot sector of a drive mapped to a device on a device based driver it calculates a 16 bit checksum of the boot sector contents and stores it together with the rest of the disk parameters 11 e When Nextor asks the driver for device change status and the reply is not sure it re reads the boot sector of the drive and calculates the checksum again If it matches the
26. ess of the number of devices controlled by the driver This overrides the normal behavior in which Nextor assigns one drive per device found see 3 2 Booting Nextor Note that this key will also affect the floppy disk drive if any the second drive emulation will be disabled e 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 e 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 Q for primary slot 1 A for primary slot 2 QWER for slots 1 0 to 1 3 respectively ASDF for slots 2 0 to 2 3 respectively ZXCV for slots 3 0 to 3 3 respectively In the rare event that you have a Nextor kernel at slot 0 use the keys UIOP for 0 0 to 0 3 respectively O oOo 6 O 0O Q Example if your Nextor kernel is in primary slot 1 press Q to prevent it from booting If you have it in slot 2 3 press F 2 10 Built in partitioning tool The Nextor kernel has a built in device partitioning tool that can be started by just executing CALL FDISK in the BASIC prompt It can be used to create partitions of any size between 100KB and 4GB on devices controlled by Nextor device based drivers See 3 5 The built in partitioning tool 2 11 Embedded
27. g tool will create MSX DOS 2 boot sectors for all partitions of 32MB or less and standard boot sectors for larger partitions 3 2 1 Booting in DOS 1 mode Nextor kernel can boot in MSX DOS 1 mode This will happen if anything of the following conditions is met e The computer has no mapped memory or the largest mapper has less than 128K e The boot drive has a MSX DOS 1 boot sector boot sectors not having standard format or MSX DOS 2 format will be considered MSX DOS 1 boot sectors e The 1 key or the 2 key is kept pressed while booting 10 The boot procedure for MSX DOS 1 mode is the same as for the normal MSX DOS 2 compatible mode with the following differences e During the automatic mapping procedure only the MSX DOS 1 compatible partitions will be examined These are FAT 12 partitions with three or less sectors per FAT e After the automatic mapping procedure the NEXTOR SYS and COMMAND2 COM search step is omitted Partitions of 16MB or less created with the built in disk partitioning tool will have three sectors per FAT or less so these can be used in MSX DOS 1 mode Remember that MSX DOS 1 can boot the DOS environment MSXDOS SYS and COMMAND COM if the computer has 64K of RAM Otherwise only Disk BASIC can be used On MSX Turbo R computers the CPU mode will be switched to Z80 when booting in MSX DOS 1 mode unless the 2 key is pressed during boot see 2 9 Boot keys Note when booting directly in th
28. he screen when in doubt look for an indication on what to do next in the lower line of the screen There are however some points of interest to consider that are not mentioned in the tool itself e The tool allows creating up to 256 FAT12 and FAT16 partitions on any block device attached to a Nextor device based driver MSX DOS drivers and Nextor drive based drivers are not supported e With this tool it is not possible to add new partitions to an already partitioned device All existing partitions must be removed before defining new partitions e Partitions from 100KB the minimum supported partition size up to 32MB will be FAT 12 partitions from 33MB to 4GB the maximum supported partition size will be FAT 16 e Partitions of 16MB or less will have three sectors per FAT or less therefore they can be used in MSX DOS 1 mode e Partitions up to 32MB will have a MSX DOS 2 boot sector partitions of 33MB and more will have a standard boot sector e lf four partitions or less are defined they will be created as primary partitions If five partitions or more are defined then the first one will be primary and the others will be extended partitions contained within the second primary partition Remember that Nextor only scans primary partitions during the automatic drive to device and partition mapping process e To get an optimum cluster size it is recommended to define the partition sizes as powers of two that is 1M 2M 4M 8M 16M or 3
29. ich allow applications to allocate 16K RAM segments Nextor maintains the original routines but provides two new ones that allow allocating a contiguous block of memory from 1 byte to 16K inside a given segment See the Nextor 2 0 Programmers Reference for details 2 9 Boot keys The boot time configuration of Nextor can be modified by keeping pressed some special keys while the system is booting These keys and their behavior are 1 Force boot in MSX DOS 1 mode If the computer is a MSX Turbo R switches CPU to Z80 mode 2 Force boot in MSX DOS 1 mode If the computer is a MSX Turbo R switches CPU to R800 ROM mode Note that in MSX DOS 1 mode the active CPU is never changed when accessing disk drives this may cause some storage devices to not work properly especially those mapped to MSX DOS drivers such as floppy disk drives e 3 Force boot to the BASIC prompt ignoring any existing boot code that is do not try to load and run NEXTOR SYS AUTOEXEC BAS or the code in the boot sector e 4 for MSX Turbo R only Boot in R800 ROM mode assign the largest mapper found as the primary mapper instead of the internal mapper and free the 64K allocated for the R800 DRAM mode This is useful for using software that requires a huge amount of mapped RAM and can work only with the primary mapper note however that there is a big penalty in the system speed e CTRL Assign only one drive to each Nextor kernel with a device based driver regardl
30. ich bank is switched at boot time The MKNEXROM EXE utility has been modified to accommodate the code change explained in the previous point Corrected a bug in the Sunrise IDE driver that prevented it to work with real hardware Corrected a bug that caused the kernel code to allocate 64K RAM for the DRAM mode even on non TurboR machines causing Nextor not work on machines with only 128K of mapped RAM This has been corrected Added the note for Sunrise IDE CF users section 3 1 1 in this manual 5 9 v2 0 Alpha 2 Corrected some serious bugs related to partition management Especially one that prevented the system from booting when a completely blank device not containing any partition was attached to a device based driver The built in partitioning tool CALL FDISK now works in MSX DOS 1 mode The DSKF command now returns the drive free space in KB 28 e Added the CALL MAPDRV MAPDRVL and LOCKDRV commands e The media change behavior in MSX DOS 1 mode is now defined e Trying to map a partition to the same drive again no longer throws a Partition already in use error e Trying to access an unsupported partition type in MSX DOS 1 mode now throws a Disk I O error 6 Contact You can get the latest version of Nextor and the associated tools at Konamiman s MSX page http www konamiman com For bug reports or suggestions please write at konamiman konamiman com 29
31. mand 2 5 Reduced and zero allocation information mode Nextor allows setting drives in reduced allocation information mode When in this mode the ALLOC function which returns information about the total and free space available in a drive will return fake information if necessary so that the calculated total or free sector count will always fit in 16 bits In other words on drives with the reduced allocation information mode active when the total or free space is greater than 32MB which is possible in FAT16 volumes ALLOC will return 32MB See 3 4 6 RALLOC the reduced zero allocation information mode tool This feature is intended to avoid compatibility issues with applications that assume the underlying filesystem to be always FAT12 and therefore expect a total or free space information of up to 32MB If an environment item named ZALLOC is created with a value case insensitive of ON command SET ZALLOC ON in the command interpreter prompt the reduced allocation information mode becomes the zero allocation information mode In this case ALLOC will return a free space of zero for the drives that have this mode active This is useful because calculating the free space on a device at the end of a DIR command for example may take a somewhat long time on large devices about 4 seconds in Z80 mode for a SD card for example when the zero allocation information mode is active this time is reduced to zero The zero allocation infor
32. mation mode is available since Nextor 2 0 3 2 6 Z80 access mode In MSX Turbo R computers MSX DOS 2 always switches to the Z80 CPU when accessing a disk driver Nextor will never change the CPU when accessing drivers attached to a Nextor kernel but when accessing drivers attached to a MSX DOS kernel it is possible to have the Z80 access mode active or not When active Nextor will switch to Z80 before accessing the driver as MSX DOS does See 3 4 7 Z80MODE the Z80 access mode tool The Z80 access mode is active by default for all MSX DOS drivers It is possible to switch it on or off on a per driver basis it is not possible to change it for specific drive letters 2 Fast STROUT mode The MSX DOS function STROUT prints a string terminated with a character What this function actually does is to perform one separate call to the CONOUT function which prints one single character for every character of the string Nextor introduces the fast STROUT mode When this mode is active the string will be copied to a 512 byte buffer in page 3 and then it will be printed in one single call to the kernel code which increases the speed of the printing process The drawback is that the string length is limited to 511 bytes when this mode is active longer strings will be truncated before being displayed See 3 4 8 FASTOUT the fast STROUT mode tool 2 8 Extended mapper support routines MSX DOS 2 provides a set mapper support routines wh
33. ode will be shown 14 When a drive is in this mode the ALLOC function which returns information about the total and free space available in a drive will return fake information if necessary so that the calculated total or free sector count will always fit in 16 bits In other words on drives with the reduced allocation information mode active when the total or free space is greater than 32MB which is possible in FAT16 volumes ALLOC will return 32MB If an environment item named ZALLOC exists whose value case insensitive is ON command SET ZALLOC ON in the command interpreter then the reduced allocation information becomes the zero allocation information mode available since Nextor 2 0 3 the ALLOC function will return a free space of zero for the drives having this mode active This makes the function to return immediately which may be useful on very large or very slow devices Nextor will never modify the reduced allocation information mode status for a drive automatically it is the user who always controls this behavior Disk errors or media changes do not modify the reduced allocation information mode status either 3 4 7 ZBOMODE the Z80 access mode tool The Z80MODE COM utility which works on MSX Turbo R computers only allows activating or deactivating the Z80 access mode for a MSX DOS driver The usage syntax for ZB0MODE is Z80MODE lt driver slot gt lt driver subslot gt ON OFF If only a driver slo
34. om step 2 a In short available devices having a FAT12 or FAT16 partition are assigned to the available drives in device and logical unit number order but the first partition having a NEXTOR DAT file in the root directory has preference Note that the contents of the NEXTOR DAT file is irrelevant it may even be an empty file in future versions of Nextor this file is likely to contain some system configuration information Also note that only primary partitions are examined in the automatic mapping procedure After the automatic mapping is finished the boot procedure will continue with the following steps 1 If the 3 key is being pressed the system displays the BASIC prompt 2 Otherwise if the NEXTOR SYS and COMMAND2 COM files are present in the boot drive the first drive that is not unmapped the DOS prompt is shown after AUTOEXEC BAT is executed if present 3 Otherwise if the boot drive has a MSX DOS 1 or MSX DOS 2 boot sector its boot code is executed as in the case of MSX DOS first in the BASIC environment with the carry flag reset then in the DOS environment with the carry flag set This will usually cause MSXDOS SYS and COMMAND COM to be loaded if present 4 lf the previous step returns then the BASIC environment is activated and AUTOEXEC BAS is executed if present Note that step 3 will not be done if the disk has a standard boot sector not created by MSX DOS 1 or MSX DOS 2 The built in disk partitionin
35. ory or having less than 128K in the largest mapper Nextor will boot in MSX DOS 1 mode the DOS prompt is available only if the computer has 64K of RAM You can simply burn a standalone version of Nextor with a dummy device driver and use it together with storage controllers associated to a MSX DOS kernel You will then benefit from features such as the FAT16 filesystem support or the Z80 access mode note however that the drive to device partition mapping management feature requires a device driver specifically made for Nextor 2 Features This section overviews the features that actually make Nextor an enhanced version of MSX DOS 2 Operational details are provided in further sections 2 1 FAT16 filesystem support Nextor provides built in support for the FAT16 filesystem There is no need to install any patch and it is perfectly possible to boot the system from a FAT16 volume Volumes up to 4GB in size can be used Additionally standard boot sectors those present in factory formatted or partitioned devices or in devices formatted or partitioned by PC computers are fully supported as well In contrast MSX DOS 2 treated all disks not formatted by itself as MSX DOS 1 disks 2 2 Standardized and documented driver development system Developers of custom storage controller hardware now have a standardized and well documented system for developing custom drivers The driver structure the details about the routines to be implemented and
36. ot 1 B for driver on slot 2 C for the internal disk drive which is affected by CTRL as well The internal disk drive would not have any drives attached if you pressed SHIFT while booting see 2 9 Boot keys 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 The procedure is repeated for each driver and is as follows 1 Start with the first drive associated to the first Nextor device based driver found 2 Start with the first logical unit on the first device available 3 Scan all the existing primary partitions If one of them has a FAT12 or FAT16 filesystem which has a file named NEXTOR DAT in the root directory map it to the drive If the drive has no valid partition table search for one single filesystem at device sector zero If step 3 fails repeat it with the next logical unit available in the device If step 3 fails for all the logical units on the device repeat it with the next device 6 If step 3 fails for all the devices repeat from step 1 but this time do not search a NEXTOR DAT file that is map the first FAT12 or FAT16 partition available 7 If step 6 fails there are no usable partitions available leave the drive unmapped 8 Repeat steps 2 7 for the other drives assigned to the driver if any but skipping the logical units already assigned to a drive 9 Go to the next device based driver if any and repeat fr
37. previously stored checksum Nextor assumes that the device has not been changed Otherwise it assumes that the device has changed and it performs the same mapping procedure as when the driver reports a device change It is recommended to lock drives mapped to removable devices in order to avoid unnecessary media checks and unnecessary boot sector reads and checksum calculations 3 3 1 Media changes in MSX DOS 1 mode When Nextor is running in MSX DOS 1 mode media changes are not managed for drives mapped to device based drivers For these drives Nextor will assume that the medium does never change and therefore will never ask for change status information to the driver if the medium is changed it is necessary to manually inform Nextor about the change by issuing a CALL MAPDRV command from the BASIC prompt 3 4 The command line tools Nextor is supplied with a set of tools that allow managing the new capabilities available All of these tools are COM files intended to be executed from within the DOS prompt This section explains how to use these tools Note however that you can also get a summary of the parameters accepted by each tool by invoking it without parameters more detailed help is available as well by displaying the desired file directly with the TYPE command for example TYPE MAPDRV COM All the tools rely on the new function calls provided by Nextor for its behavior If you are a developer and want to know more details
38. s gt is the address of the assembler code to be executed Value 1 is treated as a special case _USR 1 will do nothing but will not throw an error You can use this feature together with the ON ERROR GOTO command to detect the presence of Nextor from within a BASIC program lt registers address gt is the address of a 12 byte buffer for the Z80 registers values If this parameter is specified the registers will be loaded with the contents of this area before the code is invoked after the code execution the reverse process is performed the buffer is updated with the values hold by the registers The order of the registers in the buffer is F A C B E D L H IXI IXh IYI Yh Here is a simple BASIC program to test the CALL USR command Change the registers assignment in lines 40 90 and the address of the code to be invoked in line 100 as appropriate to invoke different code the MSX BIOS itself is a good source of routines to play around 10 ON ERROR GOTO 20 _USR 1 ON ERROR GOTO 0 GOTO 30 20 PRINT Nextor not found END 30 DEFINT R DIM R 12 40 R 0 amp H2100 AF 50 R 1 amp H3040 BC 60 R 2 amp H5060 DE 70 R 3 amp H7080 HL 80 R 4 amp H90A0 IX 90 R 5 amp HBOCO IY 100 CALL USR amp HOO0A2 VARPTR R 0 Prints a passed in A as amp H21 110 PRINT AF amp H HEXS R 0 120 PRINT BC amp H HEXS
39. t is specified the current Z80 access mode state for the driver will be shown The Z80 access mode is set or unset on a per driver basis it is not possible to change it for specific drive letters The Z80 access mode can be set or unset on MSX DOS drivers only Nextor will never switch the current CPU when accessing a Nextor driver When set Nextor will switch the current CPU to Z80 prior to performing any operation with the driver When not set Nextor will not change the current CPU when accessing the driver Whether a given MSX DOS driver needs the Z80 access mode to be set or not depends on each driver when in doubt look at the driver documentation or ask the driver developer if at all possible Floppy disk drives are likely to need the Z80 access mode to be active At boot time Nextor will activate the Z80 access mode for all MSX DOS drivers Other than that Nextor will never automatically change the Z80 access mode for any driver it is the user who always controls this behavior 3 4 8 FASTOUT the fast STROUT mode tool The FASTOUT COM utility allows to switch on an off the fast STROUT mode The usage syntax for FASTOUT is FASTOUT ON OFF When invoked without parameters it will show the current status of the FASTOUT mode The MSX DOS function STROUT prints a string terminated with a character What this function actually does is to perform one separate call to the CONOUT function which prints one single character for
40. t work in terms of driver units but directly in terms of devices This means that the driver has no routines like Read sector X of unit N but rather Return information of device X and Read raw data from device X A device based driver can handle up to seven devices and each device can have from one to seven logical units The best part is that when using device based drivers Nextor will handle the assignment of devices and partitions to drive letters both automatically at boot time see 3 2 Booting Nextor and manually by using a mapping utility that in turn invokes a new function call see 3 4 1 MAPDRV the drive mapping tool and 3 6 9 The CALL MAPDRV commana The driver developer only needs to implement raw access to the device 2 4 Drive lock Nextor allows marking drives as locked When a drive is locked the kernel code will not ask the driver if the media in the drive has changed instead it will assume that the user will never change the media This is useful when a removable device such as a multimedia card is used as the main storage device as it prevents the kernel to waste time executing media verification code Drives can be locked by using the supplied tool LOCK COM or by invoking the CALL LOCKDRV command from within the BASIC prompt All drives can be locked even those belonging to MSX DOS drivers including floppy disk drives See 3 4 5 LOCK the drive lock and unlock tool and 3 6 8 The CALL LOCKDRV com
41. the behavior of this command has been changed now returns a free KB count This behavior represents a breaking change relative to MSX DOS However most of the existing programs that use this command do not actually calculate the free space count in KB displaying the raw cluster count to the user instead Also for many years the most popular storage media for MSX computers has been the 2DD floppy disk in which the cluster size is 1K so many users were incorrectly assuming that the DSKF command was returning a KB count anyway This modification does not apply to MSX DOS 1 mode in this mode the free cluster count is still returned as a cluster count The DSKF command will always return the real free space even if the drive has the reduced allocation information mode active However if the drive has the zero allocation information mode active then the value returned will be zero 3 6 2 The DSKI and DSKO commands The DSKI function and the DSKO command which allow to read and write one disk sector respectively now accept 32 bit sector numbers therefore allowing access to any drive sector not only the first 65536 sectors In order to access sectors with numbers over 32767 the sector number must be specified as a single or double precision constant expression or variable If a single precision value is specified and the number is so big that one or more of the least significant digits of the number is lost due to truncation these comm
42. the drive will be left unmapped The optional parameter L locks the drive immediately after doing the mapping recommended for removable devices that will not be changed 3 4 2 DRIVERS the driver information tool The DRIVERS COM utility which is ran without parameters displays information about the available MSX DOS and Nextor drivers It will display the name and version for Nextor drivers only the slot number and the assigned drives at boot time MSX DOS drivers will be identified as Legacy driver This tool is useful mainly to get the slot numbers of the drivers in order to supply them as parameters to the other tools 13 3 4 3 DEVINFO the device information tool The DEVINFO COM utility displays information about the devices controlled by a given Nextor device based driver The information displayed includes the device name and manufacturer when available the device index and the associated logical units types and sizes The usage syntax for DEVINFO is DEVINFO lt driver slot gt lt driver subslot gt This tool is useful mainly to get the device and logical unit indexes in order to supply them as parameters to the MAPDRV tool 3 4 4 DRVINFO the drive information tool The DRVINFO COM utility which is ran without parameters displays information about all the available drive letters those that are not unmapped The displayed information includes the associated driver slot and other
43. the reduced zero allocation information mode tool e The system variable KANJTABLE at amp HF30F now is filled from the contents of the BIOS only if the computer has a Japanese character set This solves the corrupted error messages in some computers upgraded to MSX2 26 5 3 v2 0 2 e One of the changes in the v2 0 final Fixed a bug in the kernel code that caused a data area to be overwritten with a pointer has been rolled back It was not actually a bug and the fix was preventing Nextor from properly booting in DOS 1 mode 5 4 v2 0 1 e Corrected a bug in the kernel boot code that rendered Nextor unusable in openMSX and could potentially cause problems in real computers as well The MKNEXROM tool and the Nextor 2 0 Driver Development Guide document have been updated as well 5 5 v2 0 final e Fixed a bug in NEXTOR SYS that caused the Abort Retry Ignore message not to be displayed properly e Fixed a bug in the kernel code that caused a data area to be overwritten with a pointer 5 6 v2 0 Beta 2 e Fixed a bug that caused the RAM disk to not work properly e Fixed a bug that caused the APPEND environment variable to have no effect e At boottime the number of drives assigned to device based drivers is no longer fixed to two Instead one drive per device found is assigned see 3 2 Booting Nextor e Added the boot keys 2 4 SHIFT CTRL and the slot keys see 2 9 Boot keys e The command line tools
44. vices e Devices are reported as fixed by the driver If you are using a CF card reader and you want to change the card s you must switch off your computer hot swapping of cards is not supported 3 2 Booting Nextor The Nextor booting procedure is similar to the one performed by MSX DOS 2 However if Nextor device based drivers are present things are a little different since it is necessary to perform a drive to device and partition mapping for all the drives attached to Nextor drivers if you are not using any Nextor kernel with a device based driver attached then the booting procedure is identical to MSX DOS 2 At boot time Nextor will perform a query to all the available device based drivers to find out how many devices are being controlled by these drivers actually how many logical units but devices will usually have one single logical unit and will assign to each driver as many drives as devices are controlled by the driver If CTRL is pressed at boot time only one drive is assigned to each driver instead see 2 9 Boot keys For example assume that you have two Nextor kernels with a device based driver attached The kernel in slot 1 controls one device while the kernel in slot 2 controls three devices Then the initial drive assignment would be as follows A for driver on slot 1 B C D for driver on slot 2 E F for the internal disk drive If you boot while pressing CTRL the assignment will be A for driver on sl
45. will be thrown by the CALL MAPDRV command if you try to map a combination of partition device and driver that is already mapped on another drive You can however map the same combination to the same drive again 24 4 Other improvements 4 1 load in F7 Nextor will force the computer to boot with the load string assigned to the F7 key even on MSX1 and MSX2 computers which have cload assigned by default Note however that any code that invokes the INIFNK BIOS routine will cause the key to be assigned to cload again you can try it yourself USR amp H3E 4 2 English error messages in kanji mode If an environment item named ERRLANG is created with a value case insensitive of EN command SET ERRLANG EN in the command interpreter prompt error messages in the command interpreter will be displayed in English instead of Japanese when the kanji mode is active CALL KANJI in the BASIC interpreter This feature is available since Nextor 2 0 4 4 3 Reduced NEXTOR SYS without Japanese error messages Two variants of the NEXTOR SYS file are offered The full variant contains Japanese equivalents for part of the error messages such as the reading writing part or the Abort Retry Ignore string while the reduced variant contains only the English versions The advantage of the reduced variant is that it is smaller and using it saves 256 bytes of TPA space compared to the full version These two
46. with the drive letter followed by a colon for example A or a number being 1 to 8 for drives A to H or 0 for the current drive e lt partition gt is a number in the range 0 255 interpreted as follows o 0 Assumes that the device has no partitions The drive will be mapped to the absolute sector 0 of the device o 1 First primary partition of the device o 2 30r4 If device partition 2 is extended the number is interpreted as the first second or third extended partition respectively Otherwise the number is interpreted as the second third or fourth primary partition of the device respectively o 5orgreater The number is interpreted as the n 1 th extended partition of the device e lt device gt is a device index in the range 1 7 If the device has multiple logical units use the formula lt device gt 16 lt logical unit gt The possible values for the logical unit are 1 7 too 0 is accepted as well and interpreted as 1 e lt slot gt is a slot number in the range 0 3 If the slot is expanded use the formula lt main slot gt 4 lt subslot gt As a special case If 0 is specified as the slot number and no subslot number is specified the slot of the primary controller is used In MSX DOS 1 mode there are some additional restrictions imposed by the Nextor architecture e The specified drive must have been mapped to a device base driver at boot time It is not possible to change the mapping of a drive that was unm
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