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1988-10-10
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I. INTRODUCTION :
Terminology
Conventional memory -
It refers to the memory DOS recognizes. This memory is contained in
the computer system board and the 384K RAM card or Multifunction card
(if any). The maximum size of the conventional memory is 640 Kbytes
Expanded memory -
It is a special kind of memory that locates beyond DOS 640K-byte limit.
Application programs can make use of the expanded memory through the
Expanded Memory Manager (EMM).
RAM disk -
A RAM disk is equivalent to an additional disk drive but the storage
media is some of your computer random access memory (RAM). Unlike
an floppy disk drive, a RAM disk is all made of electronic parts, so
it works faster.
How to Get Started?
Before you can use the expanded memory in the Expanded Memory
Specification (EMS) board, you must load the Expaned Memory Manager
(EMM) driver program. MSDOS supports loading device drivers at boot
time by creating a CONFIG.SYS file. A CONFIG.SYS file is an ASCII
code (or text) file which has the following format.
DEVICE=dddddd.SYS para
dddddd.SYS is a device driver program name and para is a parameter
for the device driver. A CONFIG.SYS file may declare several device
drivers in the above format each separated by a carriage return.
When the DOS is booted up, it searches for a CONFIG.SYS file. If a
CONFIG.SYS file is found, the device drivers declared by the CONFIG.SYS
are loaded one by one.
Supplied in this diskette are three device drivers, namely EMM.SYS,
ERAMDISK.SYS and CRAMDISK.SYS. The function of each device driver
is explained in Section II.
What is the use of a RAM disk?
A RAM disk can speed up a program which has frequent access to a
disk drive. A RAM disk can be implemented by declaring a RAM disk
device driver in CONFIG.SYS. Details of implementing a RAM disk are
described in Section III and IV. After a RAM disk is installed, it
has no file. You have to copy application programs or data files
to the RAM disk. This can be done by the COPY command (refer to DOS
manual for details). After you have finished working with your
program, any useful data file which has been modified in the RAM disk
should be copied back to your floppy diskette or hard disk drive,
since the data in RAM will be destroyed if you turn off the power or
reboot the system.
II. DEVICE DRIVERS INSIDE THE DISKETTE :
EMM.SYS - The expanded memory manager driver program
This is the driver program for the Expanded Memory Specification
(EMS) board. It must be installed before the expanded memory in the
EMS board can be used.
ERAMDISK.SYS - The RAM disk driver program for the EMS board
This is the driver program for implementing a RAM disk in the EMS
board. The RAM disk has a drive ID which is the letter next to
the drive ID letters used by the floppy disk drives and hard disk
drives in your system. For example, if your system has two floppy
drives, the drive ID of the RAM disk will be C:. If your system has
two floppy drives and one hard disk drive, the drive ID of the RAM
disk will be D: ( A: and B: are drive IDs for the floppy drives,
and C: is the drive ID for the hard disk drive).
CRAMDISK.SYS - The RAM disk driver program for the conventional
memory
This RAM disk driver program is similar to ERAMDISK.SYS but the
RAM disk occupies conventional memory. The naming of the RAM disk
drive ID is the same as that in ERAMDISK.SYS. If both ERAMDISK.SYS
and CRAMDISK.SYS are installed, they will have separate drive IDs
If this RAM disk is installed, some application programs (e.g.
SYMPHONY) which requires large conventional memory size cannot be
run.
III. INSTALLING THE DEVICE DRIVER :
To prepare a system diskette with the above device drivers, copy
the three device drivers program to your system diskette. Then
create a CONFIG.SYS file in your system diskette to invoke the
device drivers. The function of the CONFIG.SYS is to load the
device drivers at boot time. To create a CONFIG.SYS file, you can
put your system diskette in drive A: and enter the following
command.
COPY CON: A:CONFIG.SYS <CR>
DEVICE=EMM.SYS M3 I0 <CR>
DEVICE=ERAMDISK.SYS 512 <CR>
DEVICE=CRAMDISK.SYS 128 <CR>
<F6><CR>
Remark: <CR> is the ENTER key and <F6> is the F6 function key.
The above CONFIG.SYS file is only an example. The entries
M3, I0, 512, 128 are parameters for the device drivers.
They may be varied for different system configurations or
applications. If a RAM disk for conventional memory is not
required, the command line DEVICE=CRAMDISK.SYS can be
ommitted. The command line DEVICE=EMM.SYS must be entered
before DEVICE=ERAMDISK.SYS.
IV. PARAMETERS IN THE DEVICE DRIVERS :
EMM.SYS
Format : DEVICE=EMM.SYS Ma Ib Ib
M is the parameter heading defining the starting frame address of
the memory in the EMS board. the 'a' after M represents a number
which can be 0 to 7.
M parameter Starting frame address (in HEX)
-----------------------------------------------
M0 C4000
M1 C8000
M2 CC000
M3 D0000
M4 D4000
M5 D8000
M6 DC000
M7 E0000
The M parameter can be defined in any of the above values but you
must make sure that the address space of the EMS memory does not
conflict with the interface card with ROM memory. The EMS board
occupies 64K address space starting from the frame address (i.e.
if M0 is defined, EMS memory occupies address C4000-D3FFF). If
your system contains a hard disk controller card which has a
interface ROM with address C8000-CFFFF, parameter M0 or M1 should
not be used. It is recommended to use parameter M3, since the
address space does not have conflict with most common interface
cards.
I is the parameter heading defining the I/O port address of the
EMS board installed. the 'b' after I represents a number which can
be 0 to 6.
I parameter I/O port address of DIP switch setting in EMS
EMS board (in HEX) 1 2 3 4
------------------------------------------------------------------
I0 208 OFF ON ON X
I1 218 ON OFF ON X
I2 258 OFF OFF ON X
I3 268 ON ON OFF X
I4 2A8 OFF ON OFF X
I5 2B8 ON OFF OFF X
I6 2E8 OFF OFF OFF X
Remark : Pole 4 of the DIP switch may be ON or OFF
If your system is a COMPACT XT with built-in EMS memory,
the factory set I/O port address is 208 and parameter I0
should be used.
A computer system can install up to four EMS board. Each EMS
board must has its own I/O port address. There is a four pole DIP
(dual in line) switch which can be set to configure different I/O
port address. The DIP switch setting on each EMS board must be
different in order to have different I/O port address. You should
define one I parameter for one EMS board, two I parameters for
two EMS boards installed in the computer system and so forth.
For example, if you have four EMS boards in the system, you can
define the parameters as follows.
DEVICE=EMM.SYS M3 I0 I1 I2 I3
ERAMDISK.SYS
Format : DEVICE=ERAMDISK.SYS nnnn
nnnn represents a number which defines the RAM disk size in Kbyte
of memory. The minimum number is 16 and the maximum number depends
on the EMS memory size in your system. Each EMS board contains
2048 Kbytes (2 Mbytes) of memory, if the EMS board is fully filled
with RAM chips. If four EMS boards are installed in your system,
the EMS memory size is 8192 Kbytes (8 Mbytes).
(Note: If your system diskette is MSDOS version 2.0 or 2.1 the
maximum number for RAM disk is 2048. If your system diskette is
MSDOS version 3.0, 3.1, 3.2 or above the maximum number is 8192.)
CRAMDISK.SYS
Format : DEVICE=CRAMDISK.SYS nnn
nnn represents a number which defines the RAM disk size in Kbyte
of memory. The minium number is 16 and the maximum number depends
on the available conventional memory size. If you application
program requires large memory size, it is not recommended to
install this device driver.