HISTORY.TXT

7.01.08 WIP:
(30.5.2005):
- made XBDA=LOW properly handle the case when no upper memory chain is present
- added new config.sys COLOUR=xx,yy,zz to set the colour of foreground,
  background and border, respectively
- reserved more space in HMA for command.com to allow it to load high again
- added support for quoted strings in batch file arguments
- fixed BPB (BIOS parameter block) for unformatted FAT32 partitions
- fixed free space handling for FAT32 drives without File System Info Block,
  added safeguard against invalid FS Info Block
- added alternate keys <CR> and <SPACE> to answer (Y/N) question for F8-single-
  stepping and queries (? command) in config.sys; changed these routines to
  beep if wrong key has been pressed instead of simply selecting 'no'
- added option to run through the rest of config.sys in single-stepping mode by
  hitting the R or <ESC> key
(4.7.2005):
- made VOL and DIR commands skip LFNs when looking for the volume label
- changed delete file routine to also delete all LFNs preceding a dir entry
- made dir removal routine regard LFNs as empty when checking if a dir is still
  in use
- made file rename/move routine delete LFNs both for old and new entry
- fixed bug that caused the COLOUR command in config.sys to be repeated
  endlessly when it was used in single-stepping or query mode
- changed CLS command to use the colours set with the COLOUR command again
  after clearing the screen
- made COLOUR command also apply the new fore and background colour to the
  screen immediately
- also added alternate keys and run-through option to the single-stepping mode
  of autoexec.bat
(6.12.2005):
- added support for decompressing DRDOS.SYS files compressed with Pack v1.00
- added option /F to SWITCHES command, restructured config.sys processing to
  wait for F5/F8 keys after SWITCHES has been processed
- fixed bug in disk R/W routine that failed to update the LBA block number for
  subsequent read/write attempts if the previous transfer was only partially
  completed
- fixed bug in partition login routines that caused dedicated LBA partitions
  (type 0C/0Eh) within the CHS boundaries to be logged as CHS partitions
- made control flow commands GOTO/GOSUB/RETURN/EXIT/SWITCH persistent in most
  config.sys phases to make them work with (HI)INSTALLLAST
- changed routine for SWITCH command to remember the option the user selected
  in the main config.sys pass to keep it from asking again
- fixed bug that caused DR-DOS to hang on delete/rename operations when the
  boundary to the previous directory cluster was crossed while looking for
  preceding LFN entries
(15.1.2006):
- fixed bug that caused delete file operation to fail in every second cluster
  in a directory chain
- added preliminary support for 64-bit file systems
- added support for the FAT+ filesystem extension that allows files of up to
  256 GB
- added new function int 21h/AX=7142h (Long LSEEK) to allow 64-bit file pointer
  positioning
- placed additional check in read/write routine to ensure that files cannot
  become larger than the FAT+ limit (256 GB - 1)
- changed function 4E/4Fh (Find First/Next) to report a maximum file size of
  4 GB - 1
(20.8.2006):
- fixed bug in new function 7142h that caused the seek direction parameter to
  be lost
- fixed bug that caused the carry flag to be cleared when an unsupported sub
  function of DOS function 71/73h was called, causing some LFN-aware programs
  to assume that the LFN API was present
- fixed another bug in function 7142h that caused register DS not to be
  restored
- fixed yet another bug in function 7142h that caused positioning relative to
  the end of the file to change the file size instead of the file pointer
- fixed bug in free disk space computation routine that caused the next drive
  letter to become inaccessible until reboot
- added functions int 21h/AX=71A6 (Get File Info) and 21h/AX=71A7,BL=01
  (Convert DOS time to 64-bit Windows time)
(17.12.2006):
- changed disk buffer routines to no longer flush all buffers for a drive when
  a FAT sector on that drive is read into a buffer
- fixed a bug introduced by the 128 KB cluster support that caused all file
  read/write operations to be split into single cluster transfers
- added new debug routines that access the TSC of 686 CPUs to measure the
  execution time
- changed deblocked RW routine to not use preread for a buffer if the sector to
  be written is known to be unused.
- changed disk buffer routines to allow a buffer to just be tagged as in use
  instead of actually filled if it still exists, changed file RW routine to tag
  the corresponding FAT buffer when a cluster is accessed
- changed cluster allocation routines to not flush the FAT buffers for a drive
  automatically whenever a new cluster chain is allocated
- changed 32bit division routine to not use a long division if the divisor is
  a 16bit value
(21.4.2007):
- added LFN support to COMMAND.COM for DIR command
- added some preliminary code for LFN support in DEL command
- fixed a bug in DR-DOS header which had been introduced by the 64-bit file
  support that caused the file handle #3 to collide with the line input buffer,
  resulting in unpredictable behaviour if the handle was in use
- fixed bug in Int 19h routine and made it restore the XBDA segment to the
  previous address if it had been relocated with the XBDA command
(17.6.2007):
- fixed FAT size for FAT32 in BIOS Parameter Block reported by IOCTL
- made function Int 21h/AH=71h (LFN and 64-bit file support) set the carry flag
  and AX=7100h if subfunction is unsupported
- added FAT32 extension to function Int 21h/AH=53h (Translate BIOS Parameter
  Block to Drive Parameter Block)
- changed function Int 21h/AH=60h (Canonicalize Filename or Path) to also work
  on CD-ROM drives, needed by TRUENAME command and also DOSLFN
- increased maximum length of command line in COMMAND.COM to 255, removed 122
  character limit when displaying the PATH variable
- made COMMAND.COM identify its own filename and path after loading to allow it
  to properly reload its transient part if it has been renamed
(8.2.2008):
- changed input redirection routines to cancel the redirection and continue to
  read from the console device when reading from a file and EOF had already
  been reached.
- changed input redirection routine to clear register AH before calling the
  Read function to read from a file to keep it from mistake it for a device
  request header
- fixed bug that caused the allocation of the last free cluster on a FAT32
  drive to reset the free disk space info for that drive to the value
  previously present in the FS Info Sector before the allocation of the cluster
  chain
- made DIR command also use LFN API for checking whether the search string
  matches any files to prevent spurious "file not found" errors
- fixed problem with LFN assembly interface code in COMMAND.COM not restoring
  registers in use by the calling C code
- added LFN support to DEL command
- added support for LFN functions 7156h (Rename), 7160h (Expand), 713Bh
  (Change Directory), 7143h (Get/Set File Attributes) and 7147h (Get Current
  Directory) to the interface code of COMMAND.COM
- added full LFN support to DIR
- made DEL also use LFN functions for interactive mode (option /C)
- added LFN support to CD and RENAME commands
- added interface code for LFN functions 713Ah (Remove Directory) and 7139h
  (Create Directory)
- added LFN support to RD and MD commands
- added interface code for LFN function 716Ch (Create/Open File)
- added LFN support to TYPE and TRUENAME commands
(12.4.2008):
- changed TRUENAME to fail on nonexistant drives to mimic the behaviour of
  MS-DOS
- fixed bug that caused function Int 21h/AX=60h (Expand Filename) to produce
  malformed paths for SUBSTituted drives
- made DIR command display meaningful sizes for huge files on FAT+ drives if
  DOSLFN is loaded
- added missing CR LF to TRUENAME output to make piping it into FIND feasible
- fixed bug in TRUENAME that caused it to erroneously report "invalid drive
  specified" for drives that did not physically exist themselves but had been
  SUBSTituted for a physical drive
- fixed bug in TRUENAME that caused it to report spurious info for drive
  letters beyond the LASTDRIVE setting
- added LFN support to the COPY command
- increased heap size and enabled stack checks in COMMAND.COM to guard against
  heap/stack collisions
(26.7.2008):
- fixed bug in critical error handler of COMMAND.COM that triggered stack
  overflows when accessing a drive with no disk inserted and selecting the
  option "abort"
- fixed bug that caused erratic behaviour instead of displaying an error when
  RENAME was used on directories
- adjusted heap/stack size for COMMAND.COM to fix another problem with COPY
- enhanced RENAME command to also work on directories
- added option /T to DATE and TIME to simply display current date/time without
  prompting for new one
- implemented new COLOUR command for command line and batch files
(2.1.2009):
- fixed bug in CLS command that sometimes caused screen foreground/background
  colour not to be updated when COLOUR was active
- fixed bug in function Int 21h/AX=7142h (Long LSEEK) that caused only the
  lowest word of the 64-bit file pointer to be updated when moving the pointer
  relative to its current position
- made the COLOUR command in COMMAND.COM follow the driver chain to look for
  the internal CON driver if an external driver (e.g. ANSI.SYS) has been loaded
- added an option to skip AUTOEXEC.BAT when single-stepping the configuration
  files
- added proper messages when configuration files are single-stepped or skipped
  due to F8/F5 key pressed
- fixed 64 KB cluster support in BDOS loader
- fixed bug that caused the ? (Query) command in CONFIG.SYS not to execute the
  command it was used on
- fixed bug in Ctrl-C/Break handler that could cause it not to restore the
  stack properly in some cases when aborting the program
- fixed bug in functions 4E/4Fh (Find First/Next) that caused them to also find
  LFN entries in searches for only volume labels
(28.3.2009):
- made BDOS loader fall back to init drive if actual boot drive can not be
  determined, this will (hopefully) fix reported problems with some boot
  managers and non-standard MBRs
- made all password handling routines ignore file passwords for files on FAT32
  drives and for files with no access rights set to prevent hidden files
  created or modified by DOSLFN from being mistaken for password-protected
- restructured function 7142h (Long Lseek) to make it check the subfunction
  number before the file handle
- inverted error codes in function 73h since this is how error_exit expects
  them
- added limited support for function 714E/4Fh (LFN Find First/Next, but without
  LFN support) which are needed for FAT+ support in DIR
- added limited support for subfunctions 3 and 4 of function 7143h (LFN Set/Get
  Last Write Time, but without LFN support) which are used by XCOPY
(23.7.2009):
- made function 440Dh/CL=60h (IOCTL - Get Device Parameters) report 80 tracks
  instead of 40 for USB floppy disk drives
- added experimental Int13h extension (LBA) support for removable drives
- added experimental support for USB memory sticks
- fixed bug in function 714E/4Fh (LFN Find First/Next) that caused it to
  sometimes report the size of FAT+ files as 4 GB-1 instead of the actual file
  size
- fixed bug in functions 7142h (Long Lseek) and 71A6h (Get File Info) that
  caused them to silently fail when called with an invalid file handle
- changed network redirector to check whether a path that both resembles an UNC
  (networking) filename AND contains a drive letter is on a local drive before
  assuming that it is remote
- removed unnecessary restriction regarding multiple leading path separators in
  function 3Dh (Open) since it did not apply to other occurrences
(21.07.2011):
- reverted functions 1F/32h (Get DPB) to the behaviour before the 7.01.07
  (24.3.2004) WIP version so they do no longer report FAT32 drives as invalid
- added option /B "bare" to DIR command
- included option /T in help text for TIME and DATE commands

7.01.07:
- added FAT32 support to the BDOS loader to allow booting from FAT32 partitions
- added support for category code 48h (FAT32) to generic ioctl function,
  changed get and set subfunctions to use extended BPBs again, but only for
  this category
- fixed bug in device driver initialization code that called driver interrupt
  routine without checking whether its offset had been changed by the strategy
  routine, causing Himem64 to hang after unpacking
- added DOS 7 system call int 21h/AH=73h, implemented sub function 7303h (Get
  Extended Free Disk Space)
- changed dir command to use the new free disk space routine when it is
  available and kilobytes instead of bytes for large numbers
- fixed some small Watcom C/C++ 11.0c compilation problems
- fixed bugs in disk device driver that caused Get/Set Media routines to not
  read/write the serial number and label correctly on FAT16 and LBA drives
- fixed bug in Find First/Next Matching File functions that caused volume
  labels not to be found when other attributes were also given
- fixed bug in SynchroniseBuffers routine that sometimes caused data
  inconsistensies between buffers and disk
- restructured DR-DOS DDSC to make it more compatible with DOS 7 Extended DPB
  structure
- implemented function 7302h (Get Extended DPB)
- added alternate implementation of the int 25h/26h absolute disk read/write
  interface via function 7305h, for the few silly programs that try to use the
  so-called "extended" interface without checking if it is present
- changed the behaviour of functions 1Fh and 32h (Get DPB) to return error code
  FFh (invalid drive) for FAT32 drives; again, this was needed because some
  programs rely on this function to identify FAT32 drives
- changed OEM version code in function 30h from 00h (PC DOS) to EEH (DR DOS),
  changed true version as reported by function 3306h to 7.01, let SetVer
  override this as well to make Scandisk activate its FAT32 functionality
- added drive locking/unlocking functions to the disk device driver that fake
  a successful operation to make Scandisk work again after version change
- reduced maximum cluster size reported by function 36h for FAT32 partitions to
  32K to improve compatibility with existing disk tools.
- removed a rather dirty hack that was needed to work around a bug in the
  DR-DOS 7.03 boot sector code
- fixed bugs related to STACKS command
- added code to allow buffers, files, fcbs, stacks and drive table to be loaded
  in upper or high memory.
- added new config.sys commands HIFILES, HIFCBS, HISTACKS and HILASTDRIVE to
  load these data structures high even if DOS itself is loaded low
- added support for function 3001h (Get Version Flag) which is needed by
  Windows 3.x
- worked around a bug in MASM that led to errors in the DR-DOS header which was
  the reason why the taskswitcher refused to start
- fixed bugs in command.com to make comparisons in batch files with quoted
  strings work as expected
- added support for environment and internal variables on the command line
- changed function 49h (Free Memory) to merge adjacent free blocks after
  freeing a memory block
- fixed an overflow error that prevented DR-DOS from reading/writing files if
  the seek position was larger than (partition_size modulo 4 GB)
- made command.com stay resident even if not invoked with parameter /P when no
  other primary shell is installed, removed default parameters A: /P
- changed DEVICE command to not insert unnessary spaces into device driver's
  command line
- added new experimental config.sys command VERSION=x.x to allow to change the
  global version setting
- added support for block device drivers that are loaded with INSTALL in
  config.sys by increasing the number of drive letters available at boot time
  and copying the temporary logical drive table into the final one
- made some arrays in command.com static to keep nested IF commands in batch
  files from overflowing the stack
- added experimental support for drives with 128 KB cluster size (sectors per
  cluster in boot sector = 0)
- added new code to allow DDSC structures to be relocated to upper or high
  memory, added new config.sys command DDSCS=HIGH,UMB to configure this feature
  (default is DDSCS=LOW)
- added new code to also allow the DOS data segment to be relocated to upper
  memory, added new config.sys command DOSDATA=UMB to activate this (default is
  DOSDATA=LOW)
- added new code to allow the Extended BIOS Data Area to be relocated to low or
  upper memory if for some reason the memory manager fails to do this, added
  new config.sys command XBDA=LOW,UMB
- fixed a bug in the FAT32 FSInfo block handling routines that manifested after
  the DDSC relocation feature had been introduced
- fixed age-old OpenDOS bug that caused wrong value to be used for code segment
  padding which made DR-DOS hang during boot when loaded low on some machines
- made command.com ignore leading semicolons in %PATH% environment variable
- changed location of static arrays in command.com to another segment to work
  around what seems to be a bug in TaskMgr
- changed boot code so that DR-DOS will look for ibmdos.com and config.sys on
  the correct drive when booting from a second primary partition
- changed history and deblock buffer setup routines to use upper mem for these
  buffers if available
- changed FILES/FCBS to use upper memory by default if available
- changed number of internal file handles in the DOS header to four, remooved
  now obsolete command line buffer size hack
- changed floppy disk BPB table in init to use old-style BPB structure
- fixed command.com stack corruption problem when PATH is longer than 256 bytes
- fixed yet another bug from OpenDOS times that caused the RENAME command to
  corrupt the command.com stack if the new filename was longer than eight bytes
- fixed a stupid bug present since v7.01.04 that referenced some internal LBA
  variables via the wrong segment register, causing FORMAT to crash upon
  completion in recent versions with DOSDATA relocation
- introduced two new config.sys commands INSTALLLAST and HIINSTALLLAST that
  load programs after the DOSDATA segment relocation to work around problems
  with older programs that are incompatible with this feature when INSTALLed
- enhanced the VERSION=x.xx,y.yy config.sys command to also allow setting the
  True DOS Version as reported by function 3306h
- fixed code in command.com module cmdlist to work with Watcom C; changed
  default compiler for cmdlist from Borland C to Watcom C
- added support for DR-DOS 7.03 internal vars %_YEAR%, %_MONTH%, %MOY%, %_DAY%,
  %DOM%, %_DOW%, %_DOWI%, %_HOUR%, %_MINUTE%, %_SECOND%, %ERRORLEVEL%,
  %ERRORLVL%, %_ROWS%, %_COLUMNS%, %_COUNTRY% and %_CODEPAGE% to command.com
- changed the names for the kernel files to DRBIO.SYS and DRDOS.SYS; changed
  official name to "Enhanced DR-DOS"
- enhanced IF statement to also allow letters instead of numbers in ERRORLEVEL
  tests, i.e. IF ERRORLEVEL A translates into IF ERRORLEVEL 1

7.01.06:
- added support for FAT32 partition types and boot records to disk device
  driver
- expanded sector numbers in buffer management routines from 24 to 32 bit to
  allow partitions larger than 8 GB
- added FAT32 specific entries to DR-DOS file system structures
- rewrote most file system routines to cope with 32-bit cluster numbers and
  dynamic root directories (FAT32)
- added support for FAT32 file system info block to store free disk space
  to speed up disk access
- changed the free disk space routine to use dynamic cluster sizes on FAT32
  partitions to report free space more accurately
- added a routine to command.com to display large numbers with thousands
  delimiters, changed dir command to use it
- fixed bugs in the boot routine to allow booting from 64 KB cluster
  partitions
- fixed bug that caused command.com not to terminate the PSP chain at the
  master PSP, leading to all kinds of problems with the environment space
- fixed bug in dir command that caused the free disk space on partitions with
  64 KB clusters to be displayed as zero
- fixed bug in the memory allocation routine that would cause the install
  command to crash sometimes when upper memory was present
- fixed bug in LBA routines that caused writing problems on some systems, this
  may also speed up writing on other systems
- increased heap space in command.com to prevent corruption of command line
  arguments while processing deeply nested batch files
- fixed bug that sometimes caused XMSDSK to corrupt the last memory block

7.01.05:
- some preliminary changes for 32-bit file system support
- added support for 4 GB FAT16 partitions (64 KB cluster size)

7.01.04:
- added routines to convert LBA values to CHS and vice versa
- rewrote the partition registering routine to use the LBA values in the
  partition tables instead of the obsolete CHS values, disabled old code
- added int 13 extensions (LBA) support to the partition login and track r/w
  routines
- added support for partition type 0eh (FAT16B LBA)

7.01.03:
- added a hex value output routine for debugging purposes
- changed the behavior of the partition registering routine to not follow loops
  in the partition tables

7.01.02:
- changed some text strings to reflect the new version number
- slightly changed the structure of the start-up message routine
- added support for ExtendedX (type 0fh) partitions
- added a routine that checks for and displays the version number of extended
  int 13 (LBA) support
- some preliminary changes for LBA support

7.01.01 (original release):
- fixed the compilation to work with MASM 6.0b and Watcom C/C++ 10.0a
- no user-visible changes