Conserving

DOS

 

conventional

 

memory

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If

the

CD-ROM

support

 

software

is

loaded

in

DOS

conventional

memory

 

(below 640

 

KB

RAM),

 

there

might

be

insufficient

memory

 

to

run

some

 

DOS

applications.

The

 

 

CDSETUP program

attempts

to

load

the

IDE

CD-ROM

device

driver

 

and

MSCDEX

 

 

 

into

upper

 

memory,

 

when

possible,

to

avoid

 

this

problem.

 

 

 

 

 

 

 

 

See

the

following

 

topics

in

 

your

DOS

user's

guide

for

more

information

on

techniques

 

to

conserve

conventional

memory:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DOS=UMB,

DOS=HIGH,UMB

(CONFIG.SYS

entry)

 

 

 

 

 

 

 

 

 

 

 

 

 

This loads DOS high and

 

enables

the

use

of

upper

memory.

This

is

essential

to

 

effectively load MSCDEX and the

IDE

CD-ROM

device

driver

in

upper

memory.

 

 

 

HIMEM.SYS

(CONFIG.SYS

entry)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This

 

is

a

 

device

driver

that

manages

 

extended

memory

(RAM

memory

above

1

 

 

MB).

Windows

 

automatically

 

loads

this

device

driver.

 

 

 

 

 

 

 

 

 

 

EMM386.EXE

(CONFIG.SYS

entry)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This

 

is

a

 

device

driver

that

allows

 

the

extended

 

memory

made

available

by

 

 

HIMEM.SYS

to

be

 

used

 

as

expanded

memory.

The

 

MSCDEX

/E

parameter

 

 

 

 

might

 

be

used

in

 

conjunction

with

this

device

driver

to

move

 

the

cache

allocated

 

by

MSCDEX into

this

memory, thus

freeing

some

conventional

memory.

 

 

 

 

MEM

/C

/P

 

(use

from

 

DOS

prompt)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This

 

is

a

 

useful

DOS

 

utility

that

will

display

the

current

 

memory

allocation

in

 

your

computer

 

to

help

you

understand

where

device drivers and programs are

 

 

 

located.

To

display

the

 

MEM

parameters

 

available,

at

 

the

 

DOS

prompt

type

 

 

 

mem/?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Enhancing

performance

in

DOS

 

and

Windows

 

 

 

 

 

 

 

 

 

 

 

 

 

Following

are

two

 

ways

to

 

enhance

CD-ROM

performance

on

your

computer

 

when

 

 

 

using

the

 

CD-ROM

 

drive

 

with

 

DOS

or

Windows:

 

 

 

 

 

 

 

 

 

 

 

 

1. Allocate more MSCDEX cache (see /M parameter for MSCDEX).

2. Allow SMARTDRV to cache CD-ROM accesses.

The

CDSETUP

utility disables

the cache

CD-ROM

data

function.

Multi-session

CDs

are

not compatible

with

the

SMARTDRV

caching

method. If

you do

not

plan

to

use

PhotoCD

or multi-session

CDs,

you

can reenable caching by removing

the

/U

parameter

from

the SMARTDRV line in your

AUTOEXEC.BAT

or

 

CONFIG.SYS file. This might improve the performance

of

some

CD-ROM

 

applications.

You

must

have

SMARTDRV

5.0

or

higher

to

cache

CD-ROM

data.

Part 3: Appendixes

3-5

Page 37
Image 37
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