FreeDOS/docs/history.txt

2000 Oct 29 - Build 2022
-------- James Tabor (jimtabor@infohwy.com)
         Rebuild local cvs tree after a crash. Update CVS at Sourceforge.net
         with changes.

2000 Sep 04 - Build 2022
-------- James Tabor (jimtabor@infohwy.com)
+ ADD	 Adding Ron Cemer patch for Share support!

2000 Sep 04 - Build 2022
-------- James Tabor (jimtabor@infohwy.com)
+ Fixes  Brian Reifsnyder (reifsnyder@mindspring.com)
         Modified dskxfer() such that error codes are now returned.
         Functions that rely on dskxfer() have also been modified accordingly.
         Modified interrupts 0x25 & 0x26 to return more accurate error codes.
         Updated dskxfer() prototype.

2000 Aug 15 - Build 2022
-------- James Tabor (jimtabor@infohwy.com)
         2000/08/12 22:49:00  Ron Cemer (roncemer@gte.net)
         Fixed writeblock() to only use getbuf() if writing a
         complete sector; otherwise use getbloc() and do a
         read-modify-write to prevent writing garbage back
         over pre-existing data in the file.
         This was a major BUG.

2000 Aug 05 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
         Clean up and finish umb code to get 2021 out.

2000 Jul 26 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Fix    New patch from Ron IsDevice and truename fix.

2000 Jul 14 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Add    Added NLS patches from Steffen Kaiser and patch from Ron
         (roncemer@gte.net).

2000 Jun 25 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Add    Add and Fix support for UMB's.

2000 Jun 20 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Fix	 Bart Oldeman (Bart.Oldeman@bristol.ac.uk) found bugs with copy
         command using Dosemu Lredir. Fixed Dosfns return for ReadCount, 
         WriteCount and  DosGetFattr. Fixed the return in int2f.asm for
         Read/Write Remote. By adding xor ax,ax.
         I found some more return bugs in int2f.asm after adding Barts
         patch.

2000 Jun 08 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Add    Started the UMB code. Devicehigh and dos=umb only works with
         Dosemu for now.

2000 Jun 07 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Add    Int2f added code for Fastopen call.
         Now MSD Scandisk works!

2000 Jun 06 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Add    Dos Func 0x59 and found a redirector bug in fncfns.c.

2000 Jun 01 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Fix    Lastdrive is a real number 1 thru 26 not 0 thru 25.
+ Fix    Ioctl and Dsk did not return the currect AX for Ioctl calls.

2000 Jun 01 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Clean  Removed test prinf statements in source.
* Thanks to Lixing Yuan for pointing out an copy to root error.
 
2000 May 31 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Patch  Lixing Yuan (yuanlixg@china.com) Patch for parsing bug in 
	 FindFirst with wildcards -> ParseDosName (dosnames.c).

2000 May 28 - Build 2021
-------- James Tabor (jimtabor@infohwy.com)
+ Added  Open/Close/Media check to dsk.c and io.asm.
+ Fixed  Device checking in truename. Truename needs to be rewriten.

2000 May 26 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
         Code Clean up and Now the Release.

2000 May 26 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fixed  IsDevice is used in FcbFns.c and DosFns.c. I removed IsDevice
         from DosNames.c an placed it in DosFns.c. FcbFns had dup code
         and it was removed. This fixed all the functions using IsDevice.

         Truename works now. I consider it dangerous and brain damaged.
         Note: 
          truename X:\DIR\con -> X:/CON, note the '/'.
          truename foo*.* -> X:\DIR\FOO?????.???
          truename *.*\*.*\*.* -> ????????.???\????????.???\????????.???
          truename *.*\*.**\*.* -> endless Loop
             I will fix this later ;^)

         Found InitPSP running 3 time. On the 2'nd run the standard handles
         were closed with out DosClose. Now Device Drivers can Print out
         there startup info.

+ Added  New IOCTL code in Dsk.c.

2000 May 26 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fix    Kolyan Ksenev (7207@mx.csd.tsu.ru) (nik0la@acm.org)
         found Major bugs in Task.c and chario.c.

2000 May 25 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fixed  Project history.

2000 May 17 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fixed  Delete, Rename, Mkdir, and Rmdir. Comment out isDevice. There is
         a serious bug in isDevice. 
+ Added  Finished adding function code for disk serial number support.
+ Clean  Cleaned up source and removed duplicate functions.

2000 May 14 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Clean  Cleaned out the remaining CR's.

2000 May 08 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Update Started Update to the New CVS at Sourceforge.net. Setting source
         from 2018 to 2020.

2000 May 06 
-------- Jim Hall (jhall1.isd.net)
+ Import Jim Hall imported the CVS from gcfl.net to Sourceforge.net.

2000 Apr 28 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Added  Dos Function calls 0x69, and 0x6C. IOCTL support in disk driver.
         New functions not yet fully implemented. 
         Clean up DSK.C, IOCTL.C and FCBFNS.C. Removed old blk_device
         pointers.

2000 Apr 03 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fixed  All DPB chains were linking to -1.

2000 Apr 02 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ Fixed  Dos_Free returned wrong due to MaxCluster Calc.
	 Media_Check MaxCluster count wrong, needed +1.

2000 Apr 01 - Build 2020
-------- James Tabor (jimtabor@infohwy.com)
+ fixed  Unable to cd back out of cdrom directories.

2000 Mar 31 - Build 2019
-------- James Tabor (jimtabor@infohwy.com)
+ added Eric W. Biederman patches via CVS.

+ 2000 Mar 25 
+ -------- Eric Biederman
+ Fixed	 Lastdrive handling
+ Fixed	 Not enough drives for number present devices
+ Added    Working (though not perfect network redirector)
           Note: Error codes internal to freedos are negative
                 Error codes external to freedos are postive.
                 The network redirector is external to freedos...
           Note: Running the nonredirected functions on a redirected
                 drive is dangerous.   My patch is very careful
                 not to.  Except in truename.  Where (a) it is safe
                 and (b) I think it is required, and (c) it is needed
                 by dosemu.

2000 Mar 19 - Build 2019
-------- James Tabor (jimtabor@infohwy.com)
* Jean-Francois <lozevis.jeanfrancois@free.fr> email noting
  the set/clear interrupt was reverse in order.

2000 Mar 17 - Build 2019
-------- Steffen Kaiser (Steffen.Kaiser@fh-rhein-sieg.de)
+ Fixed Config.c COUNTRY= statement
+ Fixed *.c to call upFMem() when upcasing filenames
- Removed everything to load NLS into memory
= Redesigned hardcoded NLS information

--> The kernel will now return the proper information for the
    hardcoded NLS (U.S.A. / CP437), it would return the correct
    information for other NLS, too, if there would be a NLSFUNC
    available, which is not at this time.

NOTE: The way the external NLSFUNC is called does not look well, 
therfore expect a change soon.

2000 Mar 15 - Build 2019
-------- James Tabor (jimtabor@infohwy.com)
* Dennis Newbold and Massimo De Munari email kernel bug reports
  with changes to Globals.h and Inthndlr.c. Fix to leap year and
  Delete file return code.
* Michal Meller found a bug in media_check. It return the wrong
  value of sector count. Change in FATFS.C.
* Fixed Func 0x32 based on information from Marty <k3pbu@arrl.net>.
  Func 0x32 Get Drive Parameter BLK did not work.

2000 Mar 09 - Build 2018
-------- James Tabor (jimtabor@infohwy.com)
Added   CDS and made FD CDS based. Changes encompass all of the
	code for FD.
Fixed   Task.c, rewritten code from FINODE to SFT function calls.
	Unable to execute from CD. Main.c and Config.c has small
	changes.
Fixed   Device drivers are unable to write to con. Rewritten code to
	relocate DOS_PSP pointer to 050:0000. Removed references to
	DOS_PSP in DosFns.c.
Added   Network and Redirection function calls in Inthndlr.c and
	network.c.

I have a note in FatFs.c line 313, describing functions not yet
supported for networking. I don't understand Pats thoughts on SFT to
FINODE. IMHO it would have been easier to stay with SFT all through
the code.

I tested MS-Dos 6.22 Command and found it unable to do Find First or
Next. This too could explain why MSCDEX does the same thing. I only
test this with the current FDCommand at the time, so this could have
changed.

1999 Sep 24 - Build 2017
-------- John Price (linux-guru@gcfl.net)
* Per Jens Horstmeier's email, changed boot sector code to make
  Siemens CDROM's bootable.  The changes should be OK for all other
  machines too (in theory).

1999 Sep 22 - Build 2016
-------- John Price (linux-guru@gcfl.net)
* Turned off debug output from the kernel.  It does not seem to be
  necessary at this time.
* Changed boot sector to do single-sector reads instead of
  multi-sector reads.  Appearantly this was part of the reason the
  kernel would not boot from a 720K, or other format floppies.  Thanx
  to Charles Dye for the info.

1999 Sep 16 - Build 2016
-------- James Tabor (jimtabor@infohwy.com)
* Added Networking and Server Call
* Added Dos Idle call
* fixed Console.asm ConInStat

1999 Sep 13 - Build 2014
-------- John Price (linux-guru@gcfl.net)
* Deleted some files from the drivers directory that were not being
  used.
* Changed the LIB.MAK file so it would work for TC2 or TC3 or higher.
* Changed SYS.COM so that it creates a sys.log file with more debug
  information to help debug problems with making boot disks.

1999 Sep 13 - Build 2014
-------- James Tabor (jimtabor@infohwy.com)
* Submitted changes to CONSOLE.ASM & INTHNDLR.ASM to fix the INT21
  func 0B bug.

1999 Sep 13 - Build 2014
-------- Helmut Fritsch (helmut.fritsch@gcd-hs.de)
* Submitted changes to CONSOLE.ASM to fix the INT21 func 0B bug.

1999 Sep 10 - Build 2014
-------- ror4 (f2xm1@crosswinds.net)
* At the suggestion of Mr John Price, modified the int 0x25 and int
  0x26 so that they no longer update the disk buffers (int 0x26 only
  invalidates the buffers for the specified drive). This is to avoid
  inconsistent disk buffers from appearing in the buffer chain due to
  interactions between int 0x25/0x26 and file read/write operations.

1999 Aug 24 - Build 2013
-------- John Price (linux-guru@gcfl.net)
* With ideas from ror4, I redid the build batch file so you can
  specify where what make to use.
* Also created CONFIG.M and CONFIG.B which should be copied to
  CONFIG.MAK and CONFIG.BAT, respecively, and edited to reflect the
  users configuration.  This keeps new versions from replacing the
  configuration files so the user does not have to keep reseting
  their configutation.

1999 Aug 15 - Build 2013
-------- ror4 (ror4@angelfire.com)
* Patched the source so that it can be compiled with Turbo C 2.01.
  (`asm' statements were rewritten into very ugly equivalents... they
  probably need more work. :( )
* Modified the `dmatch' structure in `hdr/dirmatch.h' so that the
  `dm_dirstart' field is in the right place, and also to make it
  compile under TC 2.01, which doesn't allow bit fields of any types
  other than signed or unsigned int.
* Fixed a few minor bugs in error code returning in `kernel/fatfs.c'.

1999 Jul 16 - Build 2012
-------- ror4 (ror4@iname.com)
* Finally ported all the assembly modules to `nasm'. *phew*
* Undid plonee's patches to `kernel/fatfs.c' (sorry). They were
  causing the resulting findfirst/findnext DTA structures to be
  incompatible with MSDOS's.
* Also rewrote all the pattern copying code in `dos_findfirst' in
  `kernel/fatdir.c' to prevent a bad buffer overflow problem.
* Modified the disk buffer handling code, so that logical sector
  numbers in disk buffers are now 0-based instead of 1-based.
* int 0x25 and int 0x26 now do multi-sector reads/writes.

1999 Jul 14 - Build 2012
-------- ror4 (ror4@iname.com)
* Ported the modules in the `drivers/' branch to `nasm'.

1999 May 04 - Build 2011
-------- ror4 (ror4@cryogen.com)
* Fixed the code for converting day numbers into Julian calendar
  dates: the first and last days of each month are now returned
  correctly.
* Undid a change to the code to get the day of the week.

1999 May 02 - Build 2011
-------- John Price (linux-guru@gcfl.net)
* blockio.c: changed getblock and getbuf so that they leave at least
  3 FAT type buffers valid.  This helps because the FAT is accessed
  very often compared to other sectors.
* fatfs.c: Fixed a bug in map_cluster so it will optimize FAT reads
  on disks that have more than one sector per cluster.  This
  sigificantly improved disk access of big files on hard drives.

1999 May 02 - Build 2011
-------- ror4 (ror4@cryogen.com)
* Corrected the `struct buffer' definition in `kernel/globals.h' so
  that it corresponds exactly to Ralf Brown's description of a DOS 3.x
  buffer.
* Also fixed the problem with FATs > 255 sectors, by making use of an
  originally unused field in the buffer structure.

1999 May 01 - Build 2011
-------- ror4 (ror4@cryogen.com)
* Fixed a problem which caused disk corruption on partitions with
  FATs larger than 127 sectors. (However, FATs larger than 255
  sectors may still experience problems -- this is due to a
  limitation of the DOS 3.x buffering scheme.)
* Fixed a bug in the handling of the `stacks=' command in
  `(fd)config.sys' which caused the system to behave strangely.

1999 Apr 22 - Build 2011
-------- Steffen Kaiser (Steffen.Kaiser@fh-rhein-sieg.de)
bugfix: memmgr.c: Invalid returned largest size in MemLargest()
fix: memmgr.c: DosMemLargest: change prototype to match its useage
bugfix: inthdlr.c: 0x49: ES is decremented
fix: inthdlr.c: 0x00: DosMemCheck() does nothing --> added panic()
fix: inthdlr.c: 0x4c: DosMemCheck() does nothing --> added panic()
fix: inthdlr.c: 0x00: changed to make it the same as DOS-4C-00
	Both actions differed e.g. in ErrorMode
chg: memmgr.c: the 'name' field of the MCB is never initialized by
	DOS-48, DOS-49 or DOS-4A. Leave this to the program loading function.
bugfix: memmgr.c: adjust_far() / add_far():
	Both function together (and the way they are used) don't make sense:
	adjust_far() normalizes a far pointer, add_far() generates a linear
	address. Usually both are used this way:
		far_poi = adjust_far(far_poi);
		while(...) {
			...
			far_poi = add_far(far_poi, uword);
			...
		}
	First one makes sure that 'far_poi' is normalized, then far_poi
	becomes a linear address, which makes it very difficult to use
	it, because the possibility to get a segment warp gets very high.
	-->
		Change: add_far() also returns a normalized real mode pointer
		as adjust_far() does.
	Probably in DOS-C supporting various architecures thee functions
	served other duties, but the current useage is highly dangerous.
bugfix: task.c: ChildEnv(): nEnvSize didn't counted the last '\0'
bugfix: task.c: ChildEnv(): Allocation: maximum absolute filename to
	short and forgot the word counter
bugfix: task.c: ChildEnv(): for very corrupt environments, the
	copy function failed.
bugfix: task.c: DosExeLoader(): If exe_size > allocated_size or
	DosMemLargest() failes, the environment is not deallocated
bugfix: task.c: DosExeLoader(): Calculating the exe_size to be
	allocated. At both places (+ header.exMinAlloc & ...MaxAlloc)
	sizeof(psp) is added to exe_size. Why? image_size already
	contains sizeof(psp).
chg: task.c: DosExeLoader()/DosComLoader(): MCB patching and command
	line copying is no outside of those functions
chg: asmsupt.asm: _fbcopy: re-use parts of _bcopy
add: asmsupt.asm: fmemset, fmemclr, fmemclra {Replace the explicit
	for() loops}

1999 Apr 22 - Build 2011
-------- ror4 (ror4@cryogen.com)
* Ported boot.asm to NASM.  The plan is to port all assembly to NASM
  over time.

1999 Apr 19 - Build 2010
-------- John Price (linux-guru@gcfl.net)
* Undid the change I made to getblock below because it DID NOT speed
anything up, and in fact slowed access down.

1999 Apr 18 - Build 2009
-------- John Price (linux-guru@gcfl.net)
* change getblock so that it flushes all buffers for a drive when it
  has to flush one of them to make room.  This should speed disk
  access slightly.
* Change the boot sector so there is a compile-time option to use
  multi-sector IO or single-sector IO.  The default is multi since
  ror4 seemed to have fixed the problem we had before.

1999 Apr 18 - Build 2009
-------- ror4 (ror4@cryogen.com)
* The boot sector can now load the kernel properly from a hard disk.
* Other minor changes.

1999 Apr 16 - Build 2008
-------- ror4 (ror4@cryogen.com)
* Modified the block device driver to prepare it for multi-sector I/O
  support.  Among other things, the driver can now handle transfer
  buffers which cross DMA boundaries.
* Some other minor changes.

1999 Apr 15 - Build 2008
-------- John Price (linux-guru@gcfl.net)
* Changed mainly the map_cluster function in fatfs.c so that instead
  of starting at the beginning of the FAT chain every time, it will
  be smart about it, and start at the last FAT location that it was
  before if it can.  This speeds up disk access considerably
  especially on slower machines.

1999 Apr 15 - Build 2008
-------- Steffen Kaiser (Steffen.Kaiser@fh-rhein-sieg.de)
bugfix: ^Break handler according cmt1.txt
bugfix: DosCreat(): Detection for Devices and extension:
	the semi-colon behind if(*froot) is definitely wrong, whether
	one wants CON.EXT to be interpreted as CON or not.
bugfix: DosOpen(): dito

* Re-implementation of ^Break handler -- 1999/03/27 ska
  + Warning: The handle_break() function assumes that the InDOS flag
  was incremented (except if ErrorMode is true). Never call
  handle_break() unless the InDOS flag has been incremented within
  this reentrant call of DOS.

  + ^Break is detected and handled at certain places within the
  kernel only:  a) within the CON: device when reading or writing a
  character, and b) when entering the INT-21 service (if extended
  break checking is enabled).  At these places the process flow can
  be modified to: either a) redo the interrupted function or b) abort
  the currently running process.

  + Both actions are performed by switching back to the user stack
  and enter INT-21 handler again. If to terminate the program, AX is
  modified into 4C00h.

  + By default, if the user has no ^Break handler installed, the
  program is terminated.

  + Heavy change: The original implementation installed an unique
  INT-23 handler that directly called the actions performed
  DOS-4C-XX.  In fact, this was identically with when the user had an
  own handler installed and returned the Carry flag set, except that
  it was somewhat quicker, because the kernel need not decode the
  4C00h command.  Now the Carry flag is set prior the call of INT-23,
  so the default action is to terminate the program.

  + Note: INT-23 is called with all registers as they are passed to
  the INT-21 entry. When they are modified, they are passed
  _modified_ to the API interpreter. This also allows the DOS1-style
  termination by to load register AH with 0 (zero).

  + RBIL says:
     "any DOS call may safely be made within the INT 23 handler,
     although the handler must check for a recursive invocation if it
     does call DOS"
  This can be interpreted so or so, the problem is that the user can
  call DOS again, what would overwrite the saved _usr_stack pointer
  with a different value and, therefore, cannot be used to check if
  INT-23 was returned by RETF or RETF2/IRET.

  Because a recursive invokation of INT-23 is to prevented by the
  user, the kernel could internally save SP to somewhere else.
  However:
  a) where?
  b) is it reliable that the user ever returns from INT-23 at all?

  The implemented method uses the same mechanism as fail-safe intr()
  function is implemented: A little piece of code is constructed
  within the stack, which contains the value of SP as an operand of
  an immediate MOV instruction.


1999 Apr 13 - Build 2007
-------- ror4 (ror4@cryogen.com)
* The boot sector now moves itself to the last 512 bytes of
  conventional memory instead of a lower memory location.
* The kernel startup code has also been modified so that it works
  with the new boot sector.

1999 Apr 12 - Build 2007
-------- ror4 (ror4@cryogen.com)
* The directory scanning functions (`findfirst'/`findnext') now also
  recognize more flavours of the volume label attribute byte (namely
  0x09, 0x28 and 0x29).
* Subdirectories are now no longer assumed to have the same size as
  the root directory.
* `device/device.lib' is now included as a dependency in the kernel
  makefile.
* Removed several unused assembler modules from the `device/' branch
  (see `device/device.mak').

1999 Apr 11 - Build 2007
-------- ror4 (ror4@cryogen.com)
* The kernel now reads times from the system clock (0x40:0x6c)
  instead of the RTC. The RTC is only used during startup to
  initialize the system clock. (As a side effect of this,
  `ReadATClock' has been moved from `_TEXT' to `INIT_TEXT'.)
* Checking for leap years is now improved -- year numbers which are
  divisible by 100 but not by 400 are not counted as leap years. (Not
  that it matters for year 2000, though.)
* The scaling factor used to convert the system time count to a
  second count has been changed from 18.2 to the more accurate (?)
  19663/1080.
* Day numbers used by `clock$' are now 0-based (as in MSDOS) instead
  of 1-based. Thus 1 Jan 1980 is now day number 0.

1999 Apr 10 - Build 2007
-------- ror4 (ror4@cryogen.com)
* Added code to prevent the kernel from returning path names
  containing double backslashes.

1999 Apr 9 - Build 2007
-------- ror4 (ror4@usa.net)
* File handles are now cloned properly when a child process is spawned.
* The `DosClose' function now also frees SFT entries corresponding to
  devices, not only those entries corresponding to files.
* Removed a (minor) memory corruption bug in the code for int 0x21,
  ah = 0x09.

1999 Apr 6 - Build 2007
-------- ror4 (ror4@cryogen.com)
* Functions ax = 0x5700 and 0x5701 (get/set file date and time) now
  return the right values at the right times. (They used to return
  success when there's an error, and return error when there's a
  success.)
* Removed the `/k' switch to the linker in `sys/sys.mak'.

1999 Apr 4 - Build 2006
-------- John Price (linux-guru@gcfl.net)
* added "version=" directive so that you can change the version that
  the kernel reports.  Usage: version=<major>.<minor> (i.e.
  version=6.22)

1999 Apr 4 - Build 2006
-------- ror4 (ror4@usa.net)
* Fixed the file name parsing function (`ParseDosNames') so that it
  handles single-character path names correctly.
* Also modified the functions which call `ParseDosNames' to check its
  return value instead of assuming that it is always successful.
  (This is not currentl useful, but it will be when error checking is
  introduced into `ParseDosNames'. In other words, there'll be more
  changes to `ParseDosNames' in the near future...)

* After wondering for a long time why the kernel text segment was
  always getting corrupted when I ran DJGPP `bash' 1.14.7, I finally
  decided to examine the code occurring before the handler for int
  0x21, ah = 0x60, and I found out why... :)
* Fixed the problem of int 0x21, ax = 0x5d06 causing memory
  corruption.
* Corrected the types of `internal_data', `swap_always' and
  `swap_indos' in `kernel/globals.h'.

* Improved checking for invalid file names in `ParseDosName'
  (although I'm still not sure whether the check is water-tight or
  not).
* Changed the default path setting from `PATH=' to `PATH=.'.

* Output from character I/O functions now goes to standard output as
  it should, instead of the console. Also, there's now a clear
  distinction between console input/output and standard input/output.
* Tabs are now expanded during writes to the console device.
* Removed a hard-wired limit on the number of entries in a JFT.
  (Although I'm not sure whether this is really correct...)
* Many other changes to the file descriptor handling code.

1999 Mar 29 - Build 2006
-------- John Price (linux-guru@gcfl.net)
* Changed boot loader so it prints some feedback info while booting.
  Removed code to handle FAT12 and FAT16, and code to calculate the
  start of the fat, rootdir, and data.  Moved these functions into
  the sys command.  Now there are two versions of the boot loader
  created, one to handle FAT16, and one for FAT12.  These are
  hard-coded into the sys command, so the need for the boot.bin file
  is obsolete.
* created a new program (bin2c) to convert the boot loader binary
  file into a header file that can be included in the sys program as
  an array of bytes.

1999 Mar 29 - Build 2006
-------- ror4 (ror4@usa.net)
* Changed the class of `_BSSEND' from "STACK" to "BSS" in the
  `drivers/' branch (which I forgot about in my last patch).
* Removed all traces of the `CONST' segment, since it was causing
  `IGROUP' to be assimilated into `DGROUP', which shouldn't happen.
* Added a `(void)' cast to the `setvec' macro in `kernel/globals.h'
  (`setvec' no longer returns the original ISR vector).
* Changed an incorrect error message in `sys/sys.c'.
* Removed `drivers/setvec.asm', since it's no longer needed.
* Also removed `kernel/krnstart'.
* The name field in a process's MCB is now filled in the same manner
  as in MSDOS -- instead of being padded to the right with spaces, it
  is now terminated with '\0'. Also, if the original file name
  doesn't have an extension, the code will stop copying the file name
  at '\0' instead of continuing to look for a '.'.
* Fixed the problem of the `switchar' syscall (int 0x21, ax = 0x3700) not
  returning the correct value.


1999 Mar 28 - Build 2005
-------- ror4 (ror4@usa.net)
* Removed the need for `ipl.sys'. (!) The kernel makefile now
  statically relocates `kernel.exe' to 0x60:0 and outputs the
  resulting binary to `kernel.sys', and the boot sector has also been
  modified to load `kernel.sys' at 0x60:0 instead of `ipl.sys' at
  0x2000:0. (I chose 0x60:0 because it's the first 512-byte boundary
  occurring after the BIOS data area, 0x40:0.) Finally, `sys.com' has
  also been updated.

* Also changed the boot sector code in some other ways. In
  particular, because `kernel.sys' is rather large, I had to add some
  code to move the boot sector away from 0:0x7c00 to somewhere
  higher. (For 640K systems the boot sector will be shifted to
  0x6000:0x7c00. However, there may be problems on systems with very
  little conventional memory -- I'll probably look into this later.)

* Made some minor changes to the assembler source files so that they
  can compile on `masm'. (JP: The code still compiles fine with tasm
  too).

* Also changed several incorrect label references in the assembler
  sources. (JP: These changes fixed the "Fixup" errors we been
  talking about in the list)

* Eliminated redundant re-makes of files in the various makefiles.
  For one thing, `*.cfg' files are no longer generated from the
  makefiles, but are independent from them. (I didn't like the idea
  of having to compile an entire branch each time I edit a
  makefile...) Also, intermediate files are now retained instead of
  deleted.

* Also made some changes to `build.bat' (you'll know them when you
  see them).

* Added a file `lib/libm.mak'

* Added a file `kernel/krnstart

* The code required to initialize the kernel (or rather most of it)
  is no longer retained in memory after the initialization process is
  done. I accomplished this by moving most of the initialization code
  from `_TEXT' to a new segment named `INIT_TEXT'. Of course, I also
  had to introduce lots of other changes in order for everything to
  compile and run properly:
  - Added code to `kernel/src/kernel/kernel.asm' to move the contents
    of `INIT_TEXT' to the top of conventional memory and continue
    from there.  Control is only transferred back to `_TEXT' when the
    kernel calls `p_0'.
  - Many functions are called from both `_TEXT' and `INIT_TEXT'. To
    fix this, I created far wrappers for these functions which can
    then be called from `INIT_TEXT'. (E.g. for `execrh' there's a
    corresponding far function named `init_call_execrh' which simply
    calls `execrh' with its own parameters.) One exception to this is
    `printf' -- instead of creating a far wrapper for a near
    `printf', I created a near wrapper for a far `printf' (now called
    `init_call_printf'), because it was easier that way. :)
  - Most functions which are required only during initialization time
    were shifted into `INIT_TEXT'. (There are still some functions
    which should rightfully go into `INIT_TEXT', but are retained in
    `_TEXT' as far functions, because I found it too difficult to
    move them out. :( ) Because Turbo C only allows at most one code
    segment to be defined for each module, I had to shift some
    functions around within the source tree -- the file
    `kernel/src/kernel/proto.h' says it all.
  - A cosmetic change mentioned here for completeness: all functions
    defined in `INIT_TEXT' are now marked with the word `INIT' (in
    fact a null macro) so that the reader can easily distinguish them
    from functions defined in `_TEXT'.

* Replaced `exit' calls with `for (;;);'.

* Changed `strcpy' into a macro which calls `scopy'.

* Also redefined `setvec' to be a macro (I didn't want to waste time
  writing a far wrapper for it).

* Removed the `break_key' function in `kernel/src/kernel/kernel.asm'.

* `low_int25_handler' and `low_int26_handler' are now of type
  `void interrupt far()' instead of `void near()'. (I hope I updated
  `entry.asm' correctly -- I never tested `int 0x25' and `int 0x26'...)

* Changed the class of `_BSSEND' from "STACK" to "BSS" -- "STACK" is
  now used for a separate stack segment (`_STACK').

* Assembler modules now include `segs.inc' instead of having their
  own long list of segment definitions. (Some day I'll update the
  makefile dependencies to reflect this.)

* Also made a few minor changes to the assembler modules so that
  `masm' won't complain.

* Changed the `-X' switch in `kernel.cfg' to `-X-', so that I don't
  have to worry about C module dependencies.

* Removed the definition of `CFLAGS' from the makefile -- everything
  is now in `kernel.cfg'.

* Created a file `kernel/src/kernel/init-mod.h' which is included by
  modules whose code is supposed to go into `INIT_TEXT' instead of
  `TEXT'.

* This diff solves the problem of the MCB of a process not having a
  correct value in its name field (bug report #6).
  (The definition of the `toupper' macro is because I shifted the
  `toupper' function into `INIT_TEXT' a while ago, and therefore
  can't be called from `_TEXT' now...)


-------- John Price (linux-guru@gcfl.net)
* Made changes so you can create a directory with the same name as a
  volume label, but you still can't rename or delete it!

* Fix findfirst and findnext functions so that act as they should.
  (i.e. If the attrib has only the volume label set, then it returns
  the volume label entry in the root directory, else it returns the
  files/directories that are specified with the attrib, ignoring the
  read-only and archive bits (these are always returned).

* reorginize the source tree.  Removed IPL directory, and command.
  Moved all the file system C files into the kernel directory.
  Modifed build.bat, clean.bat, and all the make files to reflect the
  new tree.

* changed so that kernel will look for a "fdconfig.sys" file, and use
  it INSTEAD of config.sys.  If it does not find it, it will look
  for, and read config.sys, if it exists.

* Fixed so that if you call an INT 21 function with AH containing a
  unsupported function, the carry flag is set.