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1992-06-30
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Chapter 9: ERROR MESSAGES AND BUGS
9:1. List of error messages
with their meanings
9:1.1 Syntax error
The syntax for a command, calculation or condition is
incorrect.
Check what you have typed in carefully and try again.
Note that this error is sometimes produced by specifying
a column number higher than the actual number of columns
in your data table. The other likely possibility is that
the rules for correctly naming columns, variables and
macros have not been observed and the parser has
therefore become confused.
9:1.2 Missing )
A right parenthesis is missing from a calculation or
condition, or possibly some other syntax error has
occurred.
Check what you have typed in carefully and try again.
9:1.3 Blank line
A condition or other parameter is expected but has not
been entered, or begins incorrectly so is not recognised
Check what you have typed in carefully and try again.
9:1.4 Unknown command
The letters you have typed at the "Select command - "
prompt do not match any of the commands available.
Check what you have typed in carefully against the list
of commands displayed by entering HELP and try again.
9:1.5 Bad data format
EASISTAT could not read a data file properly. Probably
one of the data columns appears wider than the maximum
permitted width of 12 characters.
Make sure that you have not tried to read in a command
file or something by mistake. Check the format of the
data file using a word processor or text editor, for
example the supplied EDIT program, or using the DOS TYPE
command (described in your DOS MANUAL). To do this from
EASISTAT try entering:
SYSTEM EDIT datafile.nam
or alternatively:
SYSTEM TYPE datafile.nam |MORE
substituting the name of your data file instead of
"datafile.nam". Don't forget however that the TYPE
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Error messages and bugs
command will wrap the text round to fit onto your screen
so it may be hard to see exactly what is going on.
9:1.6 Could not open file
The file named could not be opened for reading or
writing.
Check you have given the correct name for the file, and
make sure that you have also supplied the correct drive
name and subdirectory if necessary (eg
B:\ESTAT\FIXED.DAT). You can check the names of files in
the directory by entering SYSTEM DIR. If you are writing
to a file make sure the file is not set to "Read only"
and that the disk is not "Write-protected". Make sure
that you do not have more files open at once than the
number specified on your CONFIG.SYS file. Make sure that
the disk is not full. See your DOS manual for details
concerning file names, etc.
9:1.7 Not a column
A command or condition was expecting the name of a
column. It may be that you wanted to select an option or
row instead, in which case you have not specified them
correctly.
Check what you have typed in carefully and try again.
9:1.8 Bad value
The value you have entered is not in the legal range.
Check what you have typed in carefully and try again.
9:1.9 Missing value
The command was expecting more values than you typed in.
Start the command again.
9:1.10 Mathematical error in
The program has tried to perform a calculation which is
nonsensical, like taking the log of a negative number.
Check what you have asked EASISTAT to do. You may have
given it such a calculation directly, or it may have
arisen e.g. because one whole column of a chi-squared
table has zero values in every cell. Sometimes the error
can be produced by trying to calculate the significance
of a result whose p value is practically zero, such as a
t statistic of 60. If this occurs then the result given
(p = 0.0000) is actually correct and you do not need to
worry about the error message. If you cannot see any
reason for the error then it may possibly be due to a bug
in the program. If you think this may be the case then
please inform us (see the section titled "Bugs and
crashes" below).
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Error messages and bugs
9:1.11 Out of heap memory
Either there is not enough memory available, or you have
requested an operation which would require zero memory.
Check what you have typed in carefully and see the
section below titled "Running out of memory".
9:1.12 Out of heap memory - cannot rank values
This is a special message which occurs in the BASICS
command. There is not enough memory to produce a rank
table and put the values in order, so the median,
minimum, maximum and mode cannot be determined although
the other values are output. The ranks and frequency
table cannot be produced, and nor can a graph file.
See the section below titled "Running out of memory".
9:1.13 Out of memory in realvec (or in rv2d)
Either there is not enough memory available, or you have
requested an operation which would require zero memory.
Check what you have typed in carefully and see the
section below titled "Running out of memory". This error
message can mess up the appearance of the EASISTAT
screen. If this happens you can enter SCREEN to redraw
it.
9:1.14 Stack overflow
We think you shouldn't get this message. If you do check
you have not made any syntax error. Otherwise the message
is probably due to a bug in the program, so please inform
us of it as described below in the section on bugs. In
the meantime the stack memory available for EASISTAT can
be expanded in the following way:
Save any data if necessary and quit EASISTAT. Then run
EASISTAT again by entering:
EASISTAT=30000
This allocates 30000 bytes of memory to the stack (any
value from 2000 to 30000 may be used).
9:1.15 Not ready error reading drive A Abort, Retry,
Fail?
This is a DOS error message. You have tried to access a
disk drive which has no disk in it, or has the door open.
If the error relates to the hard disk drive then there is
a fault with the disk and you should seek technical
assistance from your computer's supplier.
If you meant to access that drive then put the disk in
the drive and close the door. Then enter R. If you made a
mistake about the drive you wanted keep entering F until
the error messages stop.
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Error messages and bugs
For details of other disk error messages consult your DOS
manual.
These error messages can mess up the appearance of the
EASISTAT screen. If this happens you can enter SCREEN to
redraw it.
9:1.16 Not ready error writing device PRN Abort, Retry,
Ignore, Fail
This is a DOS error message. You have tried to access the
printer and the printer is not turned on, is not "on
line" or is not connected properly. Please note that this
message can take a minute or two before it appears (when
the printer "times out"), giving the impression that the
program has crashed (see the section on "Bugs and
crashes" below).
Get rid of the error message by repeatedly entering F
(for FAIL).
Check the printer is turned on and that the on-line
switch is on and that there is paper loaded. If this does
not solve the problem then try to check which port on
your computer the printer is connected to. If it is
connected to the first parallel (Centronics) port then
using LPT1 as a filename should send output to the
printer. If it is connected to the first or second serial
port then instead of using PRN as the printer's name use
COM1 or COM2.
Briefly here's how to find out to which port the printer
is connected:
1. Quit EASISTAT (saving your data first if necessary).
2. Using a word processor make a small file called TEST,
e.g. just containing the word "Hello". Quit the word
processor.
3. Try entering each of the following lines until one of
them works:
COPY TEST LPT1
COPY TEST LPT2
COPY TEST COM1
COPY TEST COM2
If none of them work then you've got problems (with your
system, not with EASISTAT). Check the printer port hasn't
been assigned to another port with a MODE command in your
AUTOEXEC.BAT file. If the printer is on a serial port,
make sure that the baud rate, parity and stop bits for
that port are set to the correct values for the printer
with a MODE command in your AUTOEXEC.BAT file. See your
DOS and printer manuals for detailed instructions on
connecting the printer. Good luck.
This error message can mess up the appearance of the
EASISTAT screen. If this happens you can enter SCREEN to
redraw it.
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Error messages and bugs
Note
If you have a PostScript printer then you cannot send any
plain text output to it directly. You would have to first
read the text into a word processor that is configured to
produce PostScript output and then print the text out
from that. Computers connected to networks may also need
special printing commands to print out over a network
printer and you should consult the relevant network
documentation for instructions on how to do that.
9:2. What to do if you get
an error message
There are essentially two different kinds of error
message. One is caused by the user making a mistake in
what he or she types in - a syntax error, a spelling
mistake or giving the wrong name or pathname for a file.
The other kind is when the computer runs out of memory or
runs into mathematical problems like trying to divide by
zero. Things are not quite so clear-cut, because in fact
the commonest reason for the program to produce the
second kind of error message is also because the user and
told it to do something silly, like make a chi-squared
table with zero rows. We have tried to trap most of these
errors, but a few have got through.
If you get an error message, first check carefully that
you have not made a typing mistake. If not, and
especially if you get one of the "out of memory"
messages, then it may be that you are exceeding the
program's capacity. Although we have tried to guard
against it, there is a risk that the program may crash or
"hang up", which means that absolutely nothing at all
happens when you push any of the keys. Should this happen
there will be nothing you can do except reset the
computer or turn it off and on again. Because of the risk
of this, if you get an error message which you cannot
otherwise explain we advise you immediately to save your
data to a file and to close your output and log files. Do
not save your data to the same file that you read it
from, but to a new file with a different name. All these
precautions are to minimise the risk of an error in your
program damaging ("corrupting") any of your files or
leaving you stuck unable to save your data.
9:3. Running out of memory
If you get an "Out of memory" message the most likely
reason is not that the computer is running out of memory,
but that you have asked it to do something silly which
requires zero memory, so check this first. If you get an
"Out of stack memory" message then it may be that you are
asking the program to perform an especially complicated
calculation, though to be honest we don't think that this
is likely to happen. However should it occur first check
that you have not made a mistake and then try to simplify
what you are asking the program to do, perhaps by doing
it in stages. Or see the section above on error messages
for details of expanding the available stack.
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Error messages and bugs
EASISTAT tries very hard to use as much as of the
computer's memory as it can, and to do this it ends up
putting things in all sorts of nooks and crannies. If you
find that you are running out of memory with a particular
command it is possible that the following procedure may
help:
Make sure that all the data you want saved is saved and
then quit EASISTAT. Make sure that no other programs are
running. Look in the CONFIG.SYS and AUTOEXEC.BAT files
for any "memory resident" programs. These are programs
that carry on running all the time the computer is turned
on - any "pop-up" programs that you can call up at any
time by hitting a certain key combination fall into this
category, including the pop-up calculator we provide,
EASIMATH. Also check that if you have a command to
install a "ramdrive" in your CONFIG.SYS file that the
drive is installed above the 640K DOS limit and not below
(see your DOS manual for details). If you have any of the
above commands in these two files, temporarily remove
them and then reset your computer. Enter CHKDSK to see
how much memory is available (if it asks you any
questions just enter N for "No"). As a rough guide a 640K
computer should normally have something over 590000 bytes
free. Now run EASISTAT and load the data. Then select the
command that made you run out of memory previously and
try to perform it again before you use any other
commands. If it still doesn't work then there really
isn't enough memory and all you can do is try to make
your data set smaller by deleting any columns that you
don't require for that analysis and trying again.
9:4. Bugs and crashes
Sometimes if there is something wrong with EASISTAT or
one of the other programs your computer is running at the
same time then your computer can "hang up" or "crash". If
the computer hangs up or crashes then none of the keys
you press will have any effect, except sometimes to make
a beeping noise. If this happens you are probably going
to have to reset the computer, or turn it off and on
again. Your computer will not be damaged in any way, but
any data or results not saved to disk will be lost.
Before you do this check the following points:
1. Make sure the program is not just performing a long
calculation.
2. Make sure you have not tried to send something to the
printer or "PRN" without having the printer connected,
turned on and on line. If you have then you may have to
wait a couple of minutes for the printer to "time out"
and display the "Not ready writing device PRN" message.
3. Make sure you have not tried to read or write to a
disk which is not in a drive or which has the drive door
open. If you have done this then it should time out quite
quickly and give you an error message, but it's worth
checking.
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Error messages and bugs
If none of these things have happened then the program
has crashed and you will have to reset the computer and
start again. Try to see if you can see what caused the
crash.
It is conceivable that stack overflow could cause a crash
without the "Stack overflow" message being printed. If
EASISTAT does crash and you cannot see any other reason
why then it may worth running it again with the stack set
to a higher value as described in the section above.
Bugs
A "bug" is something wrong with the way that the program
is written which causes it to behave in a way other than
that intended or expected. We aim to correct as many bugs
in EASISTAT as possible, and we aim to inform users of
any uncorrected bugs of which we are aware. However in
such a large and complex program it is always possible
that some bugs may have crept through of which we are
unaware, and so we ask users to inform us if they find
one of these so that it can be corrected or at least so
that other users can be warned of it. Sometimes a program
can behave in the way that the programmer wants it to,
but that may not be the way in which a particular user
expects it to behave. This turns into an argument about
whether something is a "bug" or a "feature". In this
manual we have try to clarify as far as possible exactly
what the program does, especially where it behaves in a
way which might not be expected.
Known bugs
Sometimes the error message produced by EASISTAT does not
give a very clear picture of what the actual problem is.
If the program runs out of room when writing a file to
disk then it will not inform you, but leave the file
incomplete. Therefore always make sure there is plenty of
room available on disk (by using the DIR command
available from DOS e.g. by entering SYSTEM DIR).
It is possible for mathematical overflow errors to occur
when performing some of the significance tests, in
particular those in which a value is divided by its
standard error and the result is taken to approximate a t
statistic as is done for regression tests. With large
numbers of values the significance test can then amount
to, for example, the probability value of t=69 with 1000
degrees of freedom. This is clearly highly significant,
but attempting to calculate the exact probability may
cause a mathematical error. The "correct" value of 0.0000
will still be given but an error will be reported. This
is harmless, but disconcerting if one does not know the
reason for it.
Unknown bugs
Apart from causing the computer to hang up, other
symptoms of bugs are that the program produces long
strings of meaningless characters and beeps, or very
large long numbers which are obviously nonsensical. Bugs
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Error messages and bugs
may also simply produce incorrect answers. We are not
aware of any that do this, but if you suspect their
existence then please let us know at once.
We would like to fix any bugs in the program, so please
do let us know of any circumstances which produce a crash
or garbage output. If you cannot see why the program
should have gone wrong at this point then please supply
us also with as much as possible of the following
information (on a disk if possible):
1. Contents of your data file.
2. Exact sequence of commands leading to crash.
3. Make and model of your computer, plus any peripheral
devices you have connected to it.
4. Contents of your AUTOEXEC.BAT and CONFIG.SYS files,
and the names of any memory-resident programs you have
loaded.
5. Version of DOS (find this out by entering VER at the
DOS prompt).
6. Version of EASISTAT (displayed when program is first
run).
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