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.