

NOVELL TECHNICAL INFORMATION DOCUMENT

DOCUMENT PROCESSING INFO:  THIS DOCUMENT REPLACES FYI-M-1116
TITLE:  Using SID to detect the location of ROM's
DOCUMENT ID:  TID800041
DOCUMENT REVISION:  A
DATE:  16AUG94
AUTHOR:  KBANTA;CEREKSON
ALERT STATUS:  Yellow
DISTRIBUTION:  Public
INFORMATION TYPE:  Symptom Solution
README FOR:  NA
NOVELL PRODUCT CLASS:

Desktop Products

NOVELL PRODUCT and VERSION:

DR DOS 6.0

CATEGORY:

Kernel

ABSTRACT:

NA

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SYMPTOM

UNABLE TO DETERMINE WHY SOME AREAS IN RAM HAVE BEEN EXCLUDED FROM USE

ISSUE/PROBLEM

After loading the EMM386.SYS memory management driver, you may notice that
the MEM /A display shows an area of upper memory as excluded from use.
After attempts to access the excluded memory area have failed, you may
suspect that some memory addressed ROM chips are occupying that area.

SOLUTION

The SID utility can be used to check on these excluded areas of memory.
This can be done by loading SID and searching the specific areas of memory
for copyright information. If a ROM is found, displaying that area in
memory may help you tell which piece of hardware is using that area in
memory.

EXAMPLE:  The following is an excerpt of a MEM /A display that shows an
area excluded at D7FF:0000 and a ROM chip at D800:0000.  The exclusion
will precede the ROM chip itself to protect the address of the ROM.


¦ CF00:0000 ¦ -------- ¦   9000h,  36,864 ¦ ---------- Upper RAM
+-----------+----------+------------------+----------------------
¦ CF00:0000 ¦   DR DOS ¦   8FF0h,  36,848 ¦ System
¦ CFE3:15C0 ¦   DR DOS ¦    DE0h,   3,552 ¦ DR DOS BIOS code
¦ D7FF:0000 ¦ EXCLUDED ¦   2010h,   8,208 ¦ Upper system memory
+-----------+----------+------------------+----------------------
¦ D800:0000 ¦ -------- ¦   2000h,   8,192 ¦ ------------- ROM ---
¦ DA00:0000 ¦ -------- ¦  16000h,  90,112 ¦ ---------- Upper RAM
+-----------+----------+------------------+----------------------
¦ DA00:0000 ¦   DR DOS ¦   9450h,  37,968 ¦ System
¦ D701:3000 ¦   DR DOS ¦   9440h,  37,952 ¦ DR DOS kernel code

Load SID to investigate the memory area in question.  SID displays the #
prompt.  Use the SR command to look for all of the possible variations of
the copyright markings.  For example, the MEM display shows something at
D800:0000, so use the command:

     SRD800:0000,FFFF,"COPYRIGHT"
       |_______|-> Change this number to investigate different
                         areas of memory.

 "COPYRIGHT","Copyright","copyright","(C)",and "(c)" should cover all of
the bases.  Notice that the search is case sensitive.  If SID finds some
data in memory that matches the search parameters, it will display the
address of that data in SEGMENT:OFFSET format. Make a note of any
addresses that are displayed.  Then display the data at each of those
locations using the D command. The company name should provide some idea
of the hardware occupying that area of memory. Displayed below is what the
investigation of the above machine revealed:

[DR DOS] C:\>SID
--------------------------------------------------
*** Symbolic Instruction Debugger ***  Release 3.2
      Copyright (c) 1983,1984,1985,1988,1990,1991,
      Inc. All Rights Reserved
--------------------------------------------------
                                        ( COMMENTS )
#SRD800:0,FFFF,"COPYRIGHT"              ( Nothing found )
#SRD800:0,FFFF,"copyright"              ( Nothing found )
#SRD800:0,FFFF,"Copyright"
D800:0056                               ( BINGO !! )
#DD800:0056                             ( Display that area )

D800:0056 43 67 68 74 20 28 43 29 20 31 39 Copyright (C) 19
D800:0066 38 42 54 72 61 6E 74 6F 72 20 53 89-90, Trantor S
D800:0076 79 73 2C 20 4C 74 64 2E 0D 0A 00 1A ystems, Ltd.....
D800:0086 00 07 73 01 CB 8D 36 34 00 E8 A6 04 ....9.s...64....
D800:0096 B8 C6 06 74 00 00 C6 06 75 00 00 C6 .@.....t....u...
#

The copyright is held by the company that made the card that connects to
the CDROM player in this particular machine. The presence of the card is
why this area of memory is excluded.

ADDITONAL REFERENCES:  DR DOS 6.0 User Guide, Appendix D

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