HP I-FILES, J-FILES application note

 Г’
Worldwide Response Center
HP 3000 APPLICATION NOTE #60
TurbolMAGE's
I-FILES
and
J-FILES
HEWLETT September 1, 1989
PACKARD Document P/N 5959-7368
HP Computer Museum
www.hpmuseum.net
For research and education purposes only.
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Copyright O 1989 by HEWLETT-PACKARD COMPANY
TurbolMAGE's I-FILES AND J-FILES
When running applications that access a data base, has a message like the following ever appeared:
de ERROR ENCOUNTERED
ASE SEND :STORE TAPE OF PRIVILEGED FILE I#######.PUB.WHATEVER
HEWLETT-PACKARD. TO DELETE THIS FILE, LOG ON IN PUB.WHATEVER
AND RUN DBDRIVER.PUB.SYS, PURGE
This message might look pretty forbidding, but it is actually a flag and a tool for finding problems in data
bases. If you have ever wondered about the how’s, why’s, and so-what’s of I-FILEs, this article will be of
great importance to you. In this article, we will introduce you to the I-FILE and discuss how to analyze
it.
This article describes:
The TurboIMAGE/V and TurboIMAGE/XL control block structures
An introduction to the uses of the new I-FILE and J-FILE of TurboIMAGE/XL
The events that could generate an I or J file
The I-FILE and J-FILE contents
Sample I and J files.
This article concludes with a case study illustrating how I-FILE analysis played a major role in problem
identification and resolution.
1. GLOBAL STRUCTURES OF TurboIMAGE/V AND TurboIMAGE/XL
An I-FILE consists of unformatted TurboIMAGE data as well as some additional user-stack information.
The TurboIMAGE data is captured in control blocks. TurboIMAGE on both V/E and XL machines, use
control block structures to control and coordinate access to a data base. In order to analyze an I-FILE, it
1s imperative that you understand the information contained in TurboIMAGE control blocks.
A. TurbolIMAGE/V CONTROL BLOCKS
TurboIMAGE/V control blocks are extra data segments used by the TurboIMAGE intrinsics to store data.
The stored data allows us to coordinate multiple access to a database. By using multiple control blocks,
TurboIMAGE overcomes the constraints of the MPE/V extra data segment size limitations. The use of
multiple control blocks also allows for more information within each data segment. The three control
blocks we will discuss are: the DBG, DBB, and DBU.
1. DBG - DATA BASE GLOBALS
The DBG data segment contains an area used for locking as well as global schema information from the
root file. The DBG allows TurboIMAGE intrinsics to quickly access required security information since
these structures are in memory and pointers are maintained in the user's stack. The DBG contains root file
information such as: access tables, set definitions, item definitions, and Native Language Support collating
sequences. This extra data segment is created before any of the other TurboIMAGE extra data segments
at the time the data base is first opened and will be the last TurboIMAGE extra data segment purged at
the time the last user in the data base does a DBCLOSE.
Each TurboIMAGE extra data segment begins with a "tag". This tag not only allows us to identify thal pre
segment belongs to TurboIMAGE, but also indicates which control block it is.
The DBG begins with the literal value "IMAGE 1“. The ОВС layout is pictured below:
DATA BASE GLOBALS
DBG
| “IMAGE1”
ACCESS INFO FOR
SETS AND ITEMS
ITEM DEFINITIONS
SET DEFINITIONS
SEQUENCE TABLE
LOCKING AREA
|
|
|
|
|
|
|
|
| NLS COLLATING
|
|
|
|
|
|
| TRAILER
|
2. DBB_- DATA BASE BUFFERS
The DBB: control block contains areas for tasks such as logging management and buffer management.
Since all TurboIMAGE 1/0 is done through buffers, the best performance is gained by coordinating the
use of the DBB buffers. The DBB allows us to do that by providing a control block whose main purpose is
to house and facilitate the coordination of all buffer usage. Logging, like buffer management, also
requires extensive coordination. Whether we are doing ILR logging, user logging, or both, we need a
monitored environment to ensure the proper application of changes. This activity also takes place within
the DBB.
This extra data segment is created at the time of the first DBOPEN after the DBG is created and will be
purged at the DBCLOSE of the last user accessing the data base.
The DBB begins with a tag of "IMAGE3". The DBB layout is pictured below:
DATA BASE BUFFERS
DBB
"ТМАСЕЗ" |
LOGGING/BUFFER
GLOBAL INFO
ILR INFORMATION
1/0 BUFFERS
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| TRAILER
|
3. DBU - DATA BASE USER DATA SEGMENT
The DBU data segment contains specific user information. A DBU will be created each time a DBOPEN is
performed on a database. For example, if the same process opens a database twice, two DBU's will be
created for that process. This is done to keep process specific access information for each open of a data
base discrete. The data retained in the DBU is item and set access information. The DBU also contains the
current list maintained for the user from the last intrinsic performed.
The DBU begins with "IMAGE?" as a tag to allow identification as a TurboIMAGE extra data segment.
The layout of DBU follows below:
DATA BASE USERS
DBU
“IMAGE2" — |
SECURITY ACCESS
TABLE FOR THIS
DBOPEN
CURRENT LIST
|
|
|
|
|
|
|
|
|
| TRAILER
|
B. TurboIMAGE/ XL CONTROL BLOCK STRUCTURES OR "MAPPED FILES”
On the XL machines, the TurboIMAGE control block structures are used for the same purpose as on
MPE/V: to store process information and coordinate access. Unlike MPE/V, though, the DBG and DBB
have been combined into a single "mapped file" called <dbname>GB. The DBU is also a mapped file which
1s, however, temporary and unnamed.
1. WHY "MAPPED" FILES ARE USED BY TurbolMAGE/XL
A "mapped file" is a file which can reside in memory or on disc or a combination of memory and disc.
The advantage of "mapped files" is that they can be accessed as virtual memory, which allows for high
speed performance. This performance increase is accomplished by taking advantage of the new
architecture’s Demand Paging to to page and prefetch (the file into main memory). No longer is there any
need for File System buffers. Main memory serves as the only buffer needed by the new file system.
Another reason for better performance is that these "mapped files" are accessed and controlled by the use
of specific pointers to direct reads within the file. These reads are controlled and maintained by the
special intrinsic: FPOINT and FCONTROL. The FREAD and FWRITE intrinsics used by
TurboIMAGE/V therefore are not required by TurboIMAGE/XL.
2. GB-FILE
The information contained in the GB-FILE is the same information contained in TurboIMAGE/V control
blocks. The major difference 1s that the DBG and DBB are combined into one "mapped" file. This
"mapped file" has a file code of -403 and is binary. Though we call it the "GB-File", its true name is
<dbname>GB where <dbname> 1s the name of the database.
® At a glance the <dbname>GB looks like this:
GB-FILE
"IMAGE1"
ACCESS INFO FOR
SETS AND ITEMS
ITEM DEFINITIONS
SET DEFINITIONS
NLS COLLATING
SEQUENCE TABLE
LOCKING AREA
DBG TRAILER
DEAD ZONE
"IMAGE3"
LOGGING
GLOBAL INFO
BUFFER HEADERS
AREA
1/0 BUFFERS
TRAILER
3. XL - DBU
The TurboIMAGE/XL DBU is also a mapped file. However, it is not permanent and does not have an
MPE file name or file code. It is a temporary file local to the process that created it with a DBOPEN. Its
structure is the same as TurboIMAGE/V DBU structure.
+
Il. 1-FILE and J-FILE STRUCTURES
A. |I-FILEs NAMING CONVENTION
This section presents how the TurboIMAGE/V control blocks and other user information are represented
in I-FILEs. Unlike cars, homes, and people, I-FILEs do not come in a variety of shapes, colors, and sizes.
They always have the same form. I-FILEs derive their name from the fact they begin with the letter "I"
coming from IMAGE. The next seven characters of the file name represent the Julian date and military
time of the I-FILE creation. The time is based on a 24-hour clock. This naming convention is similar to
the naming convention used by EDITOR and TDP for K-FILES. An I-FILE called 10031300 indicates an
I-FILE that was created on the third day of the year at 1:00 pm. The I-FILE naming algorithm is
illustrated below:
“I<ddd><tttt>" where <ddd> = Julian date (1:365)
and <tttt>= Military time (0001:2400)
The I-FILE is created in the logon group and account of the user encountering the TurboIMAGE abort.
This can be a different group and account that in which the database resides. Upon creation of an I-FILE,
TurboIMAGE will inform the user that an I-FILE was produced. If the I-FILE cannot be found, chances
are the user is looking in the wrong group and account. Usually a :LISTF I#######.@.@,2 will locate the
file.
Another distinguishing feature of an I-FILE 1s its physical characteristics. I-FILEs are created with a
negative file code which means they are privileged files. This lends extra file protection to the I-FILE
since they cannot be purged, renamed, or modified accidentally.
B. WHAT IS A J-FILE AND WHY IS IT ONLY ON THE XL?
There is a slight twist to the I-FILE concept on the XL machine. A new data structure called the
"J-FILE" was introduced along with the redefinition of the I-FILE. The J-FILE is not really a new data
structure. It is just a new name for the TurboIMAGE/V I-FILE. The J-FILE naming convention is the
same as the I-FILE so a J-FILE called J0041400 was created on the fourth day of the year at 2:00 p.m.
Like the I-FILE, the J-FILE contains the TurboIMAGE control blocks related to the aborted process: the
<DBNAME>GB and the DBU.
The MPE/XL I-FILE contains a stack marker trace and stack dump of the aborting process. This I-FILE
is built based on a script file: IMAGEDMP.PUB.SYS. A quick look at that file will reveal a series of
DEBUG commands. These commands are used to create a file containing information specific to the
environment in which the abort occurred. The IMAGEDMP.PUB.SYS file has been written by
experienced personnel to capture:
e Environmental variables
Stack marker traces
eo NM registers
CM globals and registers
C. WHY WOULD AN *I-FILE BE PRODUCED?
*(For purposes of this discussion, I-FILEs will refer to both I and J-FILEs for the MPE/XL machine and
I-FILEs on the MPE/V machine.)
An I-FILE will be produced only when certain TurboIMAGE aborts occur which call the intrinsic
DBABORT AND the database being accessed has been enabled for dumping via DBUTIL. To enable a
database for "dumping":
1) Logon as the data base creator.
2) :RUN DBUTIL.PUB.SYS
e 3) >>ENABLE <dbname> FOR DUMPING.
Once the database has been enabled for dumping, an I-FILE will be created when one of the following
conditions exist:
e INTERNAL ERROR(S) from MPE File System Intrinsics
INTERNAL INCONSISTENCY in the data base or extra data segments discovered by Image
Library Procedures.
A faulty user calling sequence
A call from a user process with the hardware DB register not pointing to the process stack.
MPE file intrinsics such as FOPEN, FREADLABEL, FREADDIR, FWRITELABEL, FWRITEDIR, or
FCLOSE impact the structure and contents of files. Any type of error when calling these procedures may
result in a TurboIMAGE abort. This type of error would be reported as either INTERNAL ERROR or
INTERNAL INCONSISTENCY. Typically the user may find or more of the following:
oe Corrupt User/File Labels
e¢ Corrupt Chain Head
e Broken Detail Chains
e Corrupted Delete Chains
e Virtual Memory Problems
e Extra Data Segment Corruption Due to Privileged Mode Programming
Why do these conditions cause TurboIMAGE to abort? Let us examine each condition to see what is taking
place and why.
At the time of FOPEN, checks are done on several areas of the file label to ensure integrity. Two of these
checks are: CHECKSUM and COLDLOAD ID. Either of these two might return an error condition which
would signal corruption.
Corrupted chains due to bad chain heads, bad detail records pointers, or broken delete chains can be
detected by FREADDIR or FWRITEDIR. A TurboIMAGE chain is simply a structure containing pointers
within the dataset. An I-FILE will be produced when these pointers do not point to a record or an
address within the file or when the pointed-to records within the file are illogical (bit-map indicates that
the record which 1s to be updated is not in use.)
Virtual Memory problems can be sensed during an FOPEN or at a time when the DBB is swapped out of
memory to enlarge or shrink the extra data segment size. The number of buffers used per accessor is
determined through the DBUTIL command SET BUFFSPECS. By varying the number of buffers used per
accessor, TurboIMAGE has to swap the DBB in and out of virtual memory. This swapping increases the
probability of problems with virtual memory. The problem will be a lack of available space to copy the
DBB from or to Virtual Memory. By setting the BUFFSPECS in DBUTIL to a constant value, say
100(1/120) this swapping will be avoided as much as possible.
Privledged mode programs in some rare cases could corrupt extra data segments, user stacks, and other
memory structures. The corruption experienced during PM processing 1s usually not intentional but is due
to improper programming or poor coding techniques. An example might include an incorrectly set
pointer. Consequences of this corruption will cause the intrinsics operating at the time to abort
unexpectedly since they return or receive unexpected results.
It is important to remember that the conditions causing an I-FILE to be created signal a serious problem.
When this problem occurs, it is informing the user that processing in this situation is questionable and that
further analysis should be done. When an I-FILE is created, all users should exit the database and the
extent of the database corruption should be determined before users are allowed to access the database.
Users will receive a message indicating that further access is not allowed and that the only TurboIMAGE
intrinsic that will be performed is a DBCLOSE of the database in question.
Though all these examples vary from case to case, the cause and effect relationship is still the same for
each case:
I-Files are created by ->
File Intrinsic Failures due to ->
Some type of corruption
A later section of this article contains two I-FILEs: one resulting from Privileged Mode program
corruption and another resulting from broken chains. The third example is an I-FILE and a J-FILE
generated by TurboIMAGE/XL showing a bad pointer, which is possibly due to a broken chain.
ll. ANALYSIS
Now that you know what an I-FILE 1s and why it is created, it 1s time to ask yourself what can be done
with it. Since an I-FILE cannot be edited or listed, how can it help? More importantly, how can I read it?
As you might have guessed an I-FILE can help by telling you almost everything you need to know about
the state of the database at the time of the I-FILE was created. The next question should be: "How can I
use an I-FILE to isolate the problem. Since an I-FILE cannot be edited or listed, how can it help me?
More importantly, how can I read it?
There is a Hewlett Packard tool that will help you "dump" the I-FILE for inspection:
DBDRIVER.PUB.SYS. DBDRIVER may be used for a wide variety of diagnostic purposes, however in
order to print an I-FILE the program must be run with the "CLONE" entry point.
— Running DBDRIVER
To access and dump the I-FILE with the DBDRIVER program, the user must satisfy one of two
conditions:
e Be the creator of the I-FILE, or
e Have PM capability
It is this program (DBDRIVER) that allows a user to "dump" an I-FILE. The formal file designator for the
output of DBDRIVER is DBDRLIST. By default, DBDRLIST is directed to "LP". The user can redirect the
dump to the terminal or to a disc file by issuing a file equation:
Terminal----------- -> ¿FILE DBDRLIST=$STDLIST
Disc---------------- > :FILE DBDRLIST;DEV=DISC;SAVE
Deferred Spoolfile--> :FILE DBDRLIST;DEV=LP,1,1
The input file can be file equated as well as the output file. This will enable the user to be signed on to a
different account and/or group than that in which the I-FILE resides. Any formal file designator may
be used:
:FILE xyz=######.PUB.WHATEVER
where *xyz is to be used when DBDRIVER prompts for the I~File name (see below) and xyz is equated to a
valid I-File.
To "dump" the file, run the DBDRIVER program as indicated below:
:RUN DBDRIVER. PUB. SYS,CLONE
The user will be prompted for the name of the file to be "cloned". The group and account cannot be
specified so make sure you are logged into the group and account in which the I-FILE exists or use a file
equation as mentioned above.
Please remember throughout this discussion that a complete analysis of an I-FILE should be conducted by
a trained Hewlett-Packard employee and that the information discussed here will allow the user a cursory
glance at the problem.
As explained earlier, the I-FILE contains a short description of the problem, a stack trace, the user stack,
and the TurboIMAGE control blocks associated with that particular database.
A typical analysis of an I-FILE would start with interpreting the ASCII message found at the beginning
of the I-FILE. These messages will include the name of the aborted TurboIMAGE intrinsic along with the
database name and abort location. For example:
ABORT: DBFIND ON DATABASE TESTDB. PUB. MY ACCT;
IMAGE ABORTS AT PROCEDURE: 000737; ADDRESS: 042046
INTERNAL TRAP ENCOUNTERED.
Although this message does not give a comprehensive report of the problem, it does tell you that a problem
occurred when executing a DBFIND on the database called TESTDB.PUB. MYACCT. At this point, it
might be in the best interest of the user to run some type of diagnostic program against the database to
verify consistency. DIOGENES, a database diagnostic program usually found in the TELESUP account,
will help identify any type of structural inconsistency.
The other information displayed in the message in this example may not be helpful to users since
TurboIMAGE source code is not available to reference the offset. But once again, this message does
identify the database affected.
Other sample messages contained in I-FILEs might read:
LOST FREE SPACE in DATASET 4% or UNABLE TO COMPLETE ILR FUNCTION.
After examining the ASCII text, the next step in I-FILE analysis is to review the error cells of the DBB.
The following table illustrates the meaning of each cell and its placement within the DBB:
10
Cell Contents MPE/V MPE/XL Comments
Error Number %100 $168-$169 bytes The TurboIMAGE error number
corresponding to the offending
aborted procedure.
Error Dataset %101 $16a-$16b bytes The dataset in which the
| error occurred.
e FS Error %102 $16c-$16d bytes The file system error returned
by the TurboIMAGE intrinsic if
appropriate.
o
File Number * %103 $16e-$16f bytes The file number assigned to the
dataset in question by the file
system. Since TurboIMAGE
datasets are globally opened,
this number will be negative.
IV. EXAMPLES OF. I-FILE AND J-FILE ANALYSIS
Following are examples of parts of actual I-FILEs and J-FILEs with a discussion of
the most pertinent areas of concern.
A. TurbolMAGE/V
1. EXAMPLE OF I-FILE SHOWING BROKEN CHAIN
This example shows portions of an I-FILE generated due to bad pointers in a sorted chain. The user who
received the error attempted to do a DBPUT to an entry with a pointer that pointed outside the dataset.
Because the database was enabled for dumping when the user attempted the DBPUT, the same message
was displayed to the user as appears at the beginning of this I-FILE.
(For brevity and readability in this article, only the pertinent information is displayed.)
ABORT: DBPUT ON DATA BASE EXAMP. PUB.SYS;IMAGE ABORTS AT PROCEDURE: 000627; A
IMAGE ABORTS AT PROCEDURE: 000627: ADDRESS: 42730
CRITICAL READ ERROR ON DATA SET #5.
END OF FILE (FSERR 0)
11
The following 1s a stack dump of the aborting procedure. This information is useful only if a map of the
procedure 1s available.
*** STACK DISPLAY **# ID # 4
S=051007 DL=177650 Z=05361
Q=051013 P=006720 LCST=S067 STAT=P,1,0L.0,
Q=050570 P=002727 LCST= $072 STAT=P,1,0,L,0,
Q=050316 P=012166 LCST= 020 STAT=U,1,1,L,0,
Q=030206 P=017201 LCST= 021 STAT=U,1,1,L,0,
Q=027723 P=020247 LCST= 021 STAT=U,1,1,L,0,
Q=027717 P=177777 LCST=S156 STATzP,1,0,L,0,
The following 1s the actual stack of the aborting program.
..D8..
-00130
-00114
-00100
-00064
-00050
-00034
-00020
-00004
00010
© 00024
OCTAL
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000.. .. .. .. ..
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000... .. .. .. ..
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000,. .. .. .
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000...
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000. . .. .. ..
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000. . .. .. .
000000 000000 000000 000000 000000 000000 0000CI 000000 022422 000000 177777 000000. .
000000 177777 000000 177777 000000 000526 002024 002044 002072 002476 003102 003112. .
003144 003164 003204 004724 004744 005064 005470 005510 005544 000000 000000 000000.d
E...
000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000... .. ..
The following is the DBB which we can tell from the value "IM AG E3" which appears as the header at
the beginning of this block of data. This data segment contains the File System error referred to in the ,
ANALYSIS section. In this data segment words %#100-%103 contain this important tracing information. (O
00000 044515 040507 042463 000367 000426 016600 002401 000000 000000 000000 000001 000000 IM AG EJ .. .
00014 000000 000000 000000 000000 000000 000002 000000 042530 040515 050040 050125 041040... ..
00030 020040 020040 046525 051120 044131 020040 024704 000006 000000 000000 176000 000000
00044 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 000000 00G000 .
00060 000000 000000 177777 000000 000000 177777 000430 002401 000000 000000 000000 000003 ..
Following are words %100-%1 03:
00074 000006 000000 000000 000000 177775 000005 000000 177770 000000 002001 000000 000000. . .
ee ‚ .. ЕХ АМР PUB
8ys ). ..
Word 4100: IMAGE ERROR NUMBER =—%177775 #-3 FREADDIR FAILURE
This means that when attempting to access an address, an error
condition occurred. For example the pointer was outside the
bounds of this dataset.
Word #101: SET NUMBER %00000$ #5 DATA SET $
The error occurred while attempting to access dataset 5.
Word %102: FILE SYSTEM ERROR 700000040 FSERR O
An FSERR 0 (END OF FILE) occurred while trying to find the values
pointed to in a chain. .
12
Word %1 03: FILE NUMBER 7177770 4-8 GLOBAL AFT ENTRY $
e The file number assigned to this file in the GLOBAL Available
File Table, which holds entries for each dataset opened, is 8.
00110 000000 000000 000000 000000 000000 000000 000223 000213 000316 000416 000470 000470.. .. .. ear ae ae. 8.8
00124 006564 000102 000074 000044 000000 006074 010000 000000 000000 000000 000000 000000. t 8 .< $. É 22 00 25 10 400
00140 000000 000000 000000 000771 000006 000000 000002 000002 000001 000003 000000 000000... .. . рее,
The following is the DBG which begins with the literal "IM AG El". Notice as well the TurboIMAGE
version 1s contained in the header of this extra data segment.
00000 044515 040507 042461 000426 000000 011554 041456 030060 032061 000367 000430 0000001М AG El .. .. .1 C. 00 41 .. .. ..
00014 000000 000000 000000 000000 000405 000417 000413 000567 000722 000725 001147 001547.. na ae a ee Wa. 0
00030 000001 000000 000000 000002 000000 000000 042530 040515 050040 050125 041040 020040.. .. .. .. .. .. EX AMP PUB
00044 020040 (046525 051120 044131 020040 000000 000000 000000 000000 000000 000000 000000 SY S .. e es an ee co me
00060 000000 000000 000000 000000 000000 000000 020040 020040 020040 020040 040100 100200.. .. .. .. .. .. ee ..
B. TurboIMAGE/XL
e 1. GETTING ABORT INFORMATION FROM TurboIMAGE/XL I-FILEs
The previous example featured an I-FILE on TurboIMAGE/V. This next example uses the I-FILE and
J-FILE on TurboIMAGE/XL.
The J-FILE contains the same data structures as the TurboIMAGE/V I-FILE. But what does the
MPE/XL I-FILE contain?
Remember that this file is produced by the Script contained in the file IMAGEDMP. PUB.SYS and that
the IMAGEDMP file should not be changed. Hewlett Packard support personnel DO have the ability to
customize this file for the purpose of retaining special information required to fully analyze the abort. It
is very important not to alter the variables, since changing or adding new parameters could cause a system
abort.
Sometimes there is detailed error message information that can be useful in determining the problem. By
using DEBUG, we can "map" into the MPE/XL I-FILE by the use of the following commands, and dump
out these error messages.
13
: DEBUG
HPDEBUG Intrinsic at: a.06d3298 hxdebug+12c
$1 ($21) nmdebug >MAP 10041403 FILECODE -403
1 10041403.EXAMP.SYS
$2 ($ac) nmdebug >
VIRT $755
VIRT $755
VIRT $755.
VIRT $755.
VIRT $755.
VIRT $755.
VIRT $755
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VIRT $755.
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VIRT $755.
VIRT $755.
VIRT $755.
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$39343038
$20202020
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$47452f58
$44424220
$44424220
$20202020
$20202020
$20202020
$20202020
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$20465245
$41544120
$20202020
$20202020
$20202020
$20202020
$20202020
$20202020
$454e4420
$45525220
$20202020
$20202020
$20202020
543a2020
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20202020
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54555242
41525453
453a2024
44524553
20202020
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4с204142
434? 4е54
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45205350
53455420
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4f 462046
30292020
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755.0 Bytes=35100
44425055
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20202020
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4f 494d41
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30303030
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424c4f 43
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$1. To dump this file out we opened the I-FILE as a mapped file
(with a file code of -403).
$2. We then display the first #150 bytes of the I-FILE and
discover the errors that the running program received:
14
ABOR
ON
STDB
L AB
EDUR
: AD
9408
GE/X
DBB
FRE
ATA
T: DBPU T
DATA BAS
.GRO UP.A
TURB OIMA
ORTS AT
E: $ 0000
DRES S: $
TURB
L AB ORTS
CONT ROL
E SP ACE
SET #11.
END OF F ILE
ERR 0)
E TE
CCT;
GE/X
PROC
0197
005e
OIMA
ON
BLOC
LOST
IN D
(FS
ABORT DBPUT ON DATA BASE TESTDB.GROUP.ACCT
TURBOIMAGE/SL ABORTS AT PROCEDURE: $00000197;ADDRESS: $005e9408
TURBOIMAGE/XL ABORTS ON DBB CONTROL BLOCK |
LOST FREE SPACE IN DATA SET #11 |
END OF FILE (FSERR 0) |
This is actually the beginning of the dump of the aborting procedure. The user who was running the
program received this message, however in most cases this message 1s not seen by anyone but the aborting
user. Often this is due to the user running a block mode application with a small window for error
messages.
2. GETTING FILE SYSTEM ERRORS FROM AN MPE/XL J-FILE
The J-FILE contains both the DBG and the DBB of the TurboIMAGE/V, otherwise known as the
GB-FILE on MPE XL. J-FILEs may be examined by running DEBUG. To use DEBUG to read the
privileged J-FILE the user must have PM capability.
Bytes $168 through $16f, on MPE/XL operating systems of 1.1, of the DBB contain the File System error
information that was contained in words 7100 through %103 of the TurboIMAGE/V DBB (see III.
ANALYSIS). Using Debug on XL, we can open the J-FILE as a mapped file, find the start of the DBB in
the J-FILE, and from there read the File System error cells.
A step-by-step example follows:
SEL
Muscrim
: DEBUG
HPDEBUG Intrinsic at: a.006d3298 hxdebug+$12c
$1 ($27) nmdebug > MAP J0041403 FILECODE -#403
1 J0041403.SANDRA.CT 354.0 Bytes=35100
$2 ($2f) nmdebug > DV 354.0,10,B
VIRT $354.0 $ 494d4147 45310000 5980000 e5980000 IMAG E1.. ....
VIRT $354.10 $ 000073da 0000432e 30303437 e598e7b4 ..s. ..C. 0047 ....
VIRT $354.20 $ 00000000 e59802fc e598026c e598058a ... eel
VIRT $354.30 $ e598071a e59807ae e59818dc e59820bc
$3 ($2f) nmdebug > DV 354.73DA*2,10,B |
VIRT $354.e7b4 $ 494d4147 45330000 e598e7b4 e5980000 IMAG E3..
VIRT $354.e7c4 $ 00010000 00000000 00000000 00000000
VIRT $354.e7d4 $ 00000000 00000000 00000000 00000000
VIRT $354.e7e4 $ 00000000 ffff0000 00000000 00000000
$4 ($2f) nmdebug > DV 354. 73DA*2+168,2 <<<remember on 1.0 to use 8A>>>
VIRT $354.e83c § fffd000d 000c0013
$5 ($2f) nmdebug > E
Refer to the Debug commands by the hex number at the beginning of each command
line.
15
$1. We open J-FILE J0041403 as a mapped file, passing the file code, -403.
$2. We display the first $10 words, in hex and ASCII. The control block @
"tag", IMAGE |, is plainly visible. From word $4 (0 relative) we
get the length of :
the DBG, $73da HALF-WORDS, not words or bytes. The DBB should trail the
DBG, and should start at that address.
$3. We display starting at BYTE $73da*2; we have multiplied the half-word
figure by two, to get bytes. We display in hex and ASCII, and
the DBB "tag", IMAGE3, tells us we made it to the right place.
$4. In the XL J-FILEs, the File System error cells are in half -words
starting at byte $168, as mentioned above. We display them, and
in this case we can learn the following:
Byte $168-169 IMAGE ERROR NUMBER $fffd #-3 FREADDIR FAILURE
This means that when attempting to access an address, an error
condition occurred. Sound familiar?
Byte $16a-16b SET NUMBER $000d #13 DATA SET 13
--The error occurred while attempting to access dataset 13.
Byte $16c-16d FILE SYSTEM ERROR $000c #12 FSERR 12
An FSERR 12 (RECORD NUMBER OUT OF RANGE) occurred. This probably
means the bad pointer was a negative number due to the sign bit being on.
Byte $16e-16f FILE NUMBER $0013 # 13 FILE NUMBER 13 CN
ON the MPE/XL machine this cell has no real meaning since we
no longer have an AFT TABLE.
V. Case Study: I-FILE Analysis Speeds Up Problem Identification
EXAMPLE OF I-FILE WITH PRIVILEGED MODE CODE VIOLATION
Using an actual call history, we will examine how the use of I-FILEs play a major role in diagnosing a
particular problem.
A user reported there were sporadic instances when Query would abort when executing a TurboIMAGE
intrinsic against a database. The following error message would be displayed on the users terminal:
ABORT: DBDELETE ON DATABASE TESTDB.GROUP.ACCOUNT;
IMAGE ABORTS AT PROCEDURE: 000737; ADDRESS: 042046
READ ERROR ON DATA SET #8
16
+-F-I-L-E---I-N-F-O-R-M-A-T-1-0-N---D-I-S-P-L-A-Y+
File Name is TESTDBOS8.GROUP. ACCOUNT
FOPTIONS: SYS,BINARY, FORMAL, F ,NOCCTL , DEQ
PHYSICAL STATUS: 777777777777777?
ERROR NUMBER: -3 RESIDUE: O
BLOCK NUMBER: O — NUMREC: 1
| |
| |
| NOLABEL |
| AOPTIONS: IN/OUT,NOMR,NOLOCK,SHR,NOBUF |
| NOMULTI , NOWAIT , NOCOPY |
| DEVICE TYPE: 3 DEVICE SUBTYPE: 8 |
| LDEV: 2 DRT: 89 UNIT: O |
| RECORD SIZE: 128 BLOCK SIZE: 128 (WORDS) |
| EXTENT SIZE: 4 MAX EXTENTS: 1 |
| RECPTR: O RECLIMIT: 2 |
| LOGCOUNT: O PHYSCOUNT: 0 |
| EOF AT: 2 LABEL ADDR: %00200247636 |
| FILE CODE: -401 ID IS USER ULABELS: 1 |
| |
| |
| |
ABORT :QUERY.PUB.SYS.%15.%12243:SYSL.%75.%11176
PROGRAM ERROR #18 :PROCESS QUIT .PARAM = 18260
PROGRAM TERMINATED IN AN ERROR STATE. (CIERR 976)
Day after day the customer experienced similar errors on different datasets in different databases. No
common thread tied these aborts together. So in order to collect more data about the aborting processes,
we suggested the user enable all their databases for dumping. At this point, I-FILES were produced each
time an abort occurred.
What follows is a step-by-step analysis of the problem. For brevity and readability, only the pertinent
information from the I-FILE is displayed.
THE ACTUAL I-FILE ITSELF
We began analyzing the I-FILE by studying the ASCII message contained in the first part of the file.
ABORT: DBDELETE ON DATA BASE TESTDB.GROUP. ACCOUNT;
IMAGE ABORTS AT PROCEDURE: 000737; ADDRESS: 042046
INTERNAL IMAGE TRAP ENCOUNTERED.
We were able to verify procedure 4737 was DBDELETE and that offset 7042046 was a call to DBABORT
by studying the TurboIMAGE code. Following the ASCII description was a dump of the stack markers.
17
*** STACK DISPLAY #*#*? ID # 15
S=003355 DL=177650 Z=00636 _
Q=003361 P=006720 LCST=S357 STAT=P,1,0L,0,CCG X=000011
Q=003136 P=002045 LCST= S356 STAT=P,1,0L,0CCG X=000004
Q=003115 P=001534 LCST=S356 STAT=P,1,0L,0CCL X=000002
Q=003072 P=004013 LCST= S356 STAT=P,1,0,L,0CCL X=000006
Q=003042 P=003147 LCST= S356 STAT=P,1,0,L,0CCL X=000002
Q=003023 P=001731 LCST=S363 STAT=P,1,0L,0,CCL X=000003
Q=002551 P=003726 LCST= 001 STAT=U,1,1,L,0,CCG X=000017
Q=002512 P=177777 LCST=S156 STAT=P,1,0,L,0,CCG X=000000
This also allowed us to verify that DBDELETE was calling DBABORT. Following the dump of the stack
markers was the user stack itself. At this point we were able to verify that the parameters passed from
QUERY to DBDELETE were correct.
The TurboIMAGE control blocks followed the user stack dump. Rather than listing all control blocks
(some of which are over %10000 words), we will discuss only those pertinent to user analysis.
After finding the DBB by searching for the "IM AG E3" tag,we preceded to dump out the error cells in
words %100 - %103: - |
00074 000025 000000. 000000 000000 177775 000010 000110 177132 000000 002001 000000 000000.. .. .. +. .. .. .H .Z ..
Word %100: IMAGE ERROR NUMBER %177775 4-3 FREADDIR FAILURE
While attempting to access an address, an error condition occurred.
The error number indicates a FREADDIR Failure.
Word 101: SET NUMBER %000010 #8 DATA SET 8
The error occurred while attempting to access dataset #8 (TESTDBOS).
Word %102: FILE SYSTEM ERROR %000110 #0 FSERR 72
This error indicates an INVALID FILE NUMBER was being used during the
particular intrinsic in question.
Word %103: FILE NUMBER %177132 #-422 GLOBAL AFT ENTRY 422
The file number assigned to this file (TESTDBOS) in the GLOBAL Available
File Table was -422.
As we collected I-Files from each aborted process, we noticed that while the error number and dataset
were different, the MPE V assigned file number was always the same: -422. This was significant, the
same file number was involved even though the databases and datasets were different. Based on our
previous experience, we knew there was a product which had in the past FCLOSEd out datasets due to a
defect in its code. Though that particular defect FCLOSEd files assigned with a number of -1, we
decided to do some further checking into that same product. Checking through the source code for this
product, it was discovered that in rare circumstances an FCLOSE of file number -422 could occur.
The point of this explanation 1s that I-FILEs allowed us to identify similarities across aborts. This was
done by analyzing words %100 - %103 of the DBB. In all of the I-FILEs produced in this case, word %103
was equal to %177132 (-422). Thus we knew we were dealing with a localized problem. Something was
FCLOSing globally opened files whose file number was -422. Since we knew that the customer was
18
running the same product that had in the past showed similar problems, we decided to pursue this line of
O investigation which correctly led us to the problem and the subsequent solution.
19
BACK ISSUE INFORMATION
Following 15 a list of the Application Notes published to date. If you would like to order single copies of
back issues please use the Reader Comment Sheet attached and indicate the number(s) of the note(s) you
need.
Note # Published
7 2/21/85
2 10/15/85
3 4/01/86
4 4/15/86
5 5/01/86
6 5/15/86
7 6/01/86
8 6/15/86
9 7/01/86
10 7/15/86
11 8/01/86
42 8/15/86
13 9/01/86
14 9/15/86
15 10/01/86
16 10/15/86
17 11/01/86
18 11/15/86
19 12/01/86
20 1/01/87
21 1/15/87
22 2/15/87
23 3/01/87
24 3/15/87
25 4/01/87
26 4/15/87
27 5/01/87
28 5/15/87
29 6/01/87
30 6/15/87
31 7/01/87
32 7/15/87
33 8/15/87
34 9/01/87
34 10/01/87
35 10/15/87
34 11/01/87
36 12/01/87
37 12/15/87
38 1/01/88
39 1/15/88
40 2/01/88
41 4/01/88
42 7/15/88
43 7/15/88
44 8/01/88
45 8/15/88
46 8/15/88
Topic
Printer Configuration Guide (superseded by note #4)
Terminal types for HP 3000 HPIB Computers (superseded by note #13)
Plotter Configuration Guide
Printer Configuration Guide - Revised
MPE System Logfile Record Formats
Stack Operation
COBOL 11/3000 Programs: Tracing Illegal Data
KSAM Topics: COBOL's Index 1/0; File Data Integrity
Port Failures, Terminal Hangs, TERMDSM
Serial Printers - Configuration, Cabling, Muxes
System Configuration or System Table Related Errors
Pascal/ 3000 - Using Dynamic Variables
Terminal Types for HP 3000 HPIB Computers - Revised
Laser Printers - A Software and Hardware Overview
FORTRAN Language Considerations - A Guide to Common Problems
IMAGE: Updating to TurboIJM AGE & Improving Data Base Loads
Optimizing VPLUS Utilization
The Case of the Suspect Track for 792X Disc Drives
Stack Overflows: Causes & Cures for COBOL II Programs
Output Spooling
COBOLII and MPE Intrinsics
Asynchronous Modems
VFC Files
Private Volumes
TurbolM AGE: Transaction Logging
HP 2680A, 2688A Error Trailers
HPTrend: An Installation and Problem Solving Guide
The Startup State Configurator
A Programmer's Guide to VPLUS/ 3000
Disc Cache
Calling the CRE ATEPROCESS Intrinsic
Configuring Terminal Buffers
Printer Configuration Guide
RIN Management (Using COBOLII Examples) (A)
Process Handling (Using COBOLII Examples) (B)
HPDESK 1V (Script files, FSC, and Installation Considerations)
Extra Data Segments (Using COBOLII Examples) (C)
Tips for the DESK 1V Administrators
AUTOINST: Trouble -free Updates
Store/ Restore Errors
MRJE Emulates a HASP Workstation
HP 250 / 260 to HP 3000 Communications Guidelines
MPE File Label Revealed - Revised 6/15/88
System Interrupts
Run Time Aborts
HPPA Pathing Conventions For HP3000 900 Series Processors
Vplus & Multiplexers
Setting Up An HPDesk/HPTelex For The First Time
@
47
48
49
50
51
52
53
54
55
56 -
57
58
59
60
]
1
7
9/15/88
1/15/88
2/01/88
2/15/88
. 1/01/89
1/15/89
2/01/89
4/01/89
4/15/89
- 5/01/89
6/15/89
7/01/89
8/01/89
9/01/89
Customizing Database Data Items & Changing Passwords in JCL Files
Printer Configuration (Revision #4)
Configuring DAT ACOMM Products Into MPE
VFC's For Serial Printers
Terminal Types For The HP 3000 HPIB Computers
Configuring MRJE
Using Special Characters on the 700/9x Series Terminals
Improving Database Performance
Customized Message Catalogs And Help Facilities
BRW Tips For Beginners
Configuring The HP 2334A Plus 8: Hp 23354 As A Statistical Multiplexer
HPPA Pathing Conventions For HP 3000 900 Series Processors (Update)
HP 23344 and HP 23354 Configuration Recipes
TurboIM AGE's 1-FILES and J-FILES
ay
READER COMMENT SHEET
Worldwide Response Center Support
HP 3000 Application Note 60: TurboIMAGE's I-FILES and J-FILES
(September 1, 1989)
We welcome your evaluation of this Application Note. Your comments and suggestions help us to
improve our publications. Please explain your answers under Comments, below, and use additional pages
if necessary.
Is this Application Note technically accurate? [ ] Yes [ ] No
Are the concepts and wording easy to understand? [] Yes [ ] No
Is the format of this Application Note convenient in size, arrangement and readability? [ | Yes [ | No
Comments and/or suggestions for future Application Notes:
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