Apple PC Compatibility Card - Manual (Page 191)

Setting the number of drive letters
You can share folders and volumes with the PC by assigning them to PC drive
letters. When you install your PC software, the statement
LASTDRIVE=M is
included in the CONFIG.SYS file. This allows you to view up to nine folders
or volumes at once.
To change the number of drive letters, change your CONFIG.SYS file to
include the following statement:
LASTDRIVE=x
where x is a letter between F and Z. (The PC reserves drive letters A
through E.)
Each drive letter uses 100 bytes of PC memory.
Editing the AUTOEXEC.BAT file
Your AUTOEXEC.BAT file should include the following statements:
SET TEMP=C:\TMP
SET TMP=C:\TMP
PATH=C:\DOS
LOADHIGH C:\DOS\MSCDEX.EXE /D:CDDRVR /L:E
LOADHIGH C:\APPLE\APPLEPC
C:\DOS\SMARTDRV.EXE /X
The first two lines determine the location for temporary files used by DOS
applications.
The LOADHIGH lines load Windows support and CD-ROM software into
high memory. The letter “E” at the end of the MSCDEX.EXE line assigns the
letter “E” to the CD-ROM drive. You can change it to any unused letter up to
the limit specified in the LASTDRIVE line in your CONFIG.SYS file.
The SMARTDRV line creates a disk cache to speed up DOS disk operations.
The /X option disables the write cache, which is the slower but safer option.
For best CD-ROM performance, the line containing MSCDEX.EXE must
come before the line containing SMARTDRV.EXE.
191 Setting Up the PC Environment