  noW implemented: floppy cache
                   int 0x13 LBA extensions support
                   command line arguments
                   all in one binary (TSR, unTSR, info, flush)

  not planned:     useability with EMS and 8086 (see caches.txt for
                   more information about alternative classic caches)
                   DOS block device rather than int 0x13 based cache,
                   write cache (may be offered as a separate tool).

  further notes:   CD-ROM cache is NOT part of LBAcache, BUT available
                   as SEPARATE tool (CDRcache). Read-ahead is implemented
                   in TICKLE (load it after LBAcache with floppy cache
                   enabled!) but harddisk read-ahead does not seem to
                   make a real difference on modern harddisks. Anyway,
                   you can optionally enable that when loading TICKLE.

  History of LBAcache:

  12.-13.10.2001 first working version (fixed 1024 sec buffer).
      14.10.2001 added more verbosity, statistics, round-robin search.
  18.-20.11.2001 wrote a LBA (and CHS) big version (needs more DOS RAM).
                 Default are now 2024 sectors.
      22.11.2001 Alternative "no search" dumb but fast logic for binsel.
      23.11.2001 added ability to run CHS only to the LBA version,
                 so the CHS version is discontinued. Now sys -and- com!
     -25.11.2001 lots of bugfixes and improvements, command line parsing.

      11.01.2002 added the floppy cache function: enable with FLOP ;-).
                 Also added the F (flush) option to the uncache tool.
                 Hope disk change detect and chs<->lba still work...
      22.01.2002 multi sector read collection in read.asm, various patches
                 for testing in Bochs (define to ign. missing change line,
                 hack to avoid A20 crash in XMS / Bochs BIOS int 15.87).
      25.01.2002 new option STAK to activate a 500 byte local stack
                 because FreeDOS has a -tiny- 192 byte kernel stack (!).
                 [Note 2008: kernel.asm blk_stk_top is for 192 WORDs...]
                 PLUS new options INFO SYNC STOP to access the uncache
                 functions (NO separate UNCACHE binary any more).
      28.08.2002 small cleanup and beautifying of the INFO function,
                 removed beep when detecting floppy disk change.
      10.11.2002 Added parsing for two digit size, modified binsel to
                 use less DOS RAM, added support for 8 harddisks and
                 better drive detection. Tuned some text strings :-).
  13.-15.11.2002 Made LBAcache fast again with memoization in binsel2,
                 up to 25MB XMS now, detection of lack of DOS RAM,
                 fixed MCB resizing in uncache.asm (LBAcache STOP)
                 and improved the help- and info-screens a lot.

  29.-...03.2003 made floppy geometry auto-adjust on disk change,
  ...-01.04.2003 floppies of all sizes up to 1.44 MB should work now.
      23.04.2003 fixed an important BUG that would cause LBAcache to
                 use the geometry of B: or ???: for ANY floppy...!
      26.06.2003 now using int 1e[4] as sectors/track value (floppy)
                 because (Free)DOS sets this depending on boot sector
                 contents (int 13.8.CL only tells hardware geometry).
      26.06.2003 made TICKLE part of the package.
      31.07.2003 improved help messages, changed the makefile to select  
                 less kludges and less verbosity in the default compile.
                 Added CHS harddisk support to TICKLE (experimental).
  24.-25.08.2003 made startup and info mode messages very human readable 
                 in setup / uncache, fixed "buf [0]0" in cmdline / binsel.
      27.08.2003 introducing a native .com version (old .com was .sys with
                 a 272 byte loader prepended), smaller TSR and binaries.
                 Added LBA harddisk support to TICKLE (experimental).
      22.10.2003 Cleaned up slight device handling bugs in cache and
                 tools, improved .sys parser, added "bin freezing" and
		 tickle 8k+ buffer install check.

      14.04.2004 Improved floppy size change tracking again: 13.18 bugfix,
                 Oversized floppy formats ok now? Element size now 8k in
                 default compile (instead of 4k before). Removed EECHO,
                 SYSEECHO (available as FreeDOS config.sys command EECHO
                 now) and BOOTRAND from the package. Start message fixes.
      15.04.2004 Added floppy panic protection to dispatcher rwmaybe part.
      16.04.2004 Update geometry if floppy panic protection triggered.
      01.05.2004 New STAT display (INFO minus the technical stuff).
                 DROPPED THE SYS VERSION! You can use INSTALL=LBACACHE.COM
                 if you want to load LBAcache early during boot. HELP
                 screen cleaned up. BUF now also accepts kbyte values.
                 Many cleanups, .com made some things simpler / different.
      09.05.2004 Included some TICKLE harddisk read-ahead improvements in
                 the LBACACHE package in the TICKLEHD.COM file. Normal
                 TICKLE.COM without harddisk read-ahead abilities still
                 included as well. Fixed detection / support for 1.68 MB
                 floppy geometry! Nicer STAT / INFO drive list display,
                 also suppresses leading 0s now, but not for hex values.
      09.06.2004 Faster processing of cache misses by restricting search
                 range (cache is kind of 16 way associative now instead of
                 fully associative). Better TICKLE(HD) initialization.
      17.06.2004 Fixed a stupid bug in binsel2.asm which would make the
                 N way assoc mode try to use N (usually 8k each) elements
                 more than available. Better xmscopy checks now do range
                 checking, to help debugging such problems in the future.
      15.07.2004 Fixed a bug in "block NDD int 13.ee/13.ef access" (added
                 01.05.) accidentally blocked other functions as well, in
                 particular int 13.41/13.48 (check for LBA, get LBA info)
                 which are used by tools like Partition Magic.
                 New command line options: Alloc on write "TUNW" (was on
                 all the time in older versions) and full associativity
                 "TUNA" (i.e. revert to pre 9.6. behaviour). Changed
                 files: cmdline.asm, dispatch.asm, write.asm, binsel2.asm
      24.07.2004 Added support for "allocate stack in low DOS RAM", TUNS
                 flag. This is needed because a SCSI BIOS seems to be
                 unhappy (timeout, DMA problem?) with stacks being in
                 UMBs, even for functions like int 13.08 (geometry info).
      31.08.2004 Added the improved (14aug2004) TICKLE to the LBAcache
                 "distro": The new version no longer needs a separate
                 TICKLEHD.COM file. New syntax allows /? /CHS /LBA.
                 TICKLE now avoids "tickling" virtual MEMDISK drives.
                 Size in RAM is 9.8-10.5k, depending on whether you have
                 harddisk read-ahead on or not (9k of that are buffers).
                 Fixed the tickle install check (was unused anyway: is
                 now used to avoid loading 2 TICKLES after 1 LBAcache).
      01.09.2004 added (not documented on help screen) the COOL, HEAT and
                 TEMP options to initiate freeze/melt phases. Will be
                 documented better when it turns out to be useful.
      22.09.2004 improved write error messages, changed from full flush
                 to one drive flush on write errors. ZIP now includes
                 my (19 Aug 2004) cachenotes.txt classic cache overview.
      09.06.2005 XMS handle is now locked to protect it from the chaotic
                 effects of being swapped out to a (possibly cached) disk.
                 TODO: work with disks without change line, recover from
                 diskette geometry confusion on next disk change.
      19.06.2005 XMS locking now has fewer screen messages, just works.
      31.08.2006 replaced all "retf +2" by code which uses IRET and
                 writes the carry flag on stack: LBACACHE / TICKLE now
                 always preserve the STI/CLI state of the caller, which
                 fixes a TICKLE hang with EMM386 during FDAPM FLUSH.
      18.01.2008 allow caching of "floppy A:" if A: is no real floppy,
                 even if it has no disk change check. Example: A BIOS
                 can boot USB flash memory sticks as CHS N*255*63 "A:".
                 Disable most disk change tests if A: is in DOSEMU :-)
		 Init text A:+ if > 2 heads, A:v / B:v in DOSEMU now.
      07.04.2008 alloc more stack space, 384 instead of 300/320 bytes, to
                 match the stack size available for FreeDOS block devices.
