Dunfield Development Services Inc.
Customer Support -- Application Note #0001
MICRO-C
Using a RAMdrive to speed up compilation.
Applies to: [Micro-C Compiler
]
Last updated: Sunday May 04, 2003
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PROCEDURE
The MICRO-C command co-ordinator (CCxx) runs the separate phases
of the compiler (MCP, MCCxx MCOxx, MACRO, SLINK, ASMxx), and
uses temporary files to pass the output from one phase as the
input of the next phase. By default, the temporary files are
written in the current directory.
When compiling from a physical disk drive, the system must
constantly seek back and forth between the input file, and the
output file. This slows the compiler down. A significant
performance gain can be realized by placing the temporary files
on a RAMdisk, where the seek time is essentially 0 (there
is no physical disk head).
If you do not already have a RAMdisk on your system, you can
define one by adding the following line(s) to your CONFIG.SYS
file:
For DOS 4.0 and earlier:
DEVICE=C:\DOS\VDISK.SYS 256 /E
For DOS 5.0 and later:
DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\RAMDRIVE 256 /E
Notes:
-
The indicated RAMdrive size of 256k is
adaquate for most users of the compiler. If you get disk
full messages, or errors writing to output files, try
increasing the size of the RAMdrive.
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The '/E' option causes the RAMdisk to be
allocated in extended memory (above 1mb). If you have 1mb or
less, or for some other reason do not want the RAMdisk
allocated in extended memory, you may leave the '/E' off,
and the drive will be allocated in conventional memory. If
you are not using extended memory with DOS 5.0 or later, you
may also omit the DEVICE=HIMEM.SYS line.
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After the disk size (256 in above examples),
you can specify the RAMdrive sector size, and number of root
directory entries. Refer to your DOS manual for details.
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Replace 'C:\DOS' in the above examples with
the location of the device drivers. If you are running
WINDOWS, you should use device drivers from the windows
directory.
Once you have defined a RAMdisk, you must inform
MICRO-C that it can place its temporary files there. This is
accomplished by setting the environment variable MCTMP to a
string pointing to that drive:
eg: SET MCTMP=D:\
This command should be added to your AUTOEXEC.BAT file if you
wish to always place your temporary files on the RAMdrive.
Note that MCTMP is a PREFIX, and should end with a trailing '\'
if you are intending to use it as a directory pointer. Also be
sure to change the 'D:' in the above example to the correct
drive letter of your RAMdisk if necessary.
It is common practice to place a '$' at the end of the MCTMP
prefix, so that temporary files generated by the compiler can be
easily identified:
eg: SET MDTMP=D:\$
This causes all temporary files created in D:\ to begin with the
'$' character. |
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