Command: cdrcache.sys

  CDRCACHE.SYS is a CD drive cache program. It improves the drive
  performance. Requires XMS memory, and at least a 386 computer.
  CDRCACHE.SYS has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
  When FreeDOS is already running, you can load CDRCACHE.SYS later
  with DEVLOAD.

Syntax:

  In config.sys, either:
    device=cdrcache.sys device name size
  OR:
    devicehigh=cdrcache.sys device name size

Options:

  device  The name of the CD-ROM driver device that will be cached.
  name    The name of the CD-ROM driver device that CDRcache will
          mimick. You then tell your SHSUCDX or (MSCDEX) or similar
          that your CD-ROM driver would be called like that. All
          cached requests will be handled by CDRcache, all others
          will be passed on to the real CD-ROM driver device.
  size    Specifies the XMS cache size in kilobytes, range is 238 to
          65280. Values below 100 are interpreted as size in units
          of 1/4 MBytes for backwards compatibility with CDRcache
          versions before 5/2004. Values are rounded up to multiples
          of 1/4 MByte.
  Controlling the driver after loading:
  If you do not give acceptable values for those options, an
  help screen will be displayed. Note that if you set name to
  for example "CDRCACHE" (not recommended) you might not be able
  to access files with names that start with CDRCACHE, as devices
  are opened before files when in doubt.

  Currently recognized command letters are:
  Command:
    F     Flush the cache.
    S     Show Statistics.
    I     Show statistics with extra technical Information.
    C     Clear statistics.
    Q     Quiet mode.
    N     Normal verbosity.
    V     Verbose/trace mode.
    0     Stop caching.
    1     Continue caching (after stop for instance).
    ?     Shows the help.
    name  Is the parameter passed to CDRCACHE.SYS (see example).

  All other input to the user interface is ignored.

  The new "tech info" display shows the same information as the
  "statistics" display of older CDRcaches before 5/2004. The
  normal statistics display has been beautified in newer versions
  and has been reduced to show only "easy to understand" values.

  Reading from the device currently causes statistics display
  and returns an error if you try to do it more than once every
  2 seconds (this is to throttle software that keeps reading).
  It is planned that you can read statistics this way, but for
  now, statistics are directly written to screen only.

Comments:

  Load CDRCACHE.SYS after loading your CD-ROM device driver (usually
  UDVD2.SYS).
  CDRCACHE.SYS is read cache only.
  When you start writing to your CD-R, CDRcache will go to sleep
  and stop caching data until the next disk change, to make 100%
  sure that CD-R contents and cache contents stay consistent.
  You can also issue sleep / wakeup commands manually.
  As CDRCACHE.SYS (2003) is based on LBACACHE.SYS, please read the
  LBAcache documentation for some additional technical/programming
  details.

Examples:

  In CONFIG.SYS / FDCONFIG.SYS:
    DEVICE=c:\FREEDOS\BIN\UDVD2.SYS /D:FDCD0000
    DEVICE=c:\FREEDOS\BIN\CDRCACHE.SYS FDCD0000 CDRCACH$ 2048
  Then in AUTOEXEC.BAT / FDAUTO.BAT:
    c:\FREEDOS\BIN\shsucdx /D:CDRCACH$,N
  This allocates a 2048KB (2MB) cache buffer for a single IDE CD drive.
  Controlling after loading:
    echo F > cdrcach$    (flush cache)
    echo SCF > cdrcach$  (show statistics, then clear statistics and
                         flush cache)
    echo S > cdrcach$    (only show statistics)

See also:

  autoexec.bat/fdauto.bat
  config.sys/fdconfig.sys
  device/devicehigh
  devload
 (gcdrom.sys)
  lastdrive/lastdrivehigh
  lbacache
 (mscdex)
  shsucdx
  tickle
  udvd2.sys
  uide.sys

  Copyright © 2004 Robert Platt, updated 2011 and 2022 by W. Spiegl.

  This file is derived from the FreeDOS Spec Command HOWTO.
  See the file H2Cpying for copying conditions.