CORETEST DELUXE 1.0 PRELIMINARY RELEASE DOCUMENTATION COPYRIGHT (C) 1986 BY DAVID E. FOX Congratulations. You have just added another tool to your ever-growing library of IBM PCtm utilities. Welcome to Coretest Deluxe. This program is an extensive nondestructive memory test and check utility. By "nondestructive", I mean that as the program progresses through memory, checking each byte, it first stores and later puts back each individual byte so as not to erase any important data your PC's memory may contain. Coretest Deluxe requires a minimum of version DOS 2.0 or higher, to run. It occupies very little memory space, and be- cause of its nondestructive nature, should not have any problems with memory resident programs. I have tested the program under PC DOS 3.1, using a Ram Disk and several resident programs inst- alled with no problems. The steps involved are as follows: First, the program will determine how much memory your system contains. Next, the prog- ram will go through all of your PC's memory, saving, checking, and restoring each individual byte, using a series of predeter- mined bit patterns. A bit pattern is a sequence of eight 1's and 0's, which is what the computer understands. From other memory test programs on other computers, I have found that the best sequence of bit patterns are: all zeros, (0 hexadecimal), all ones, (FF hexadecimal), and the alternating patterns of 55 and AA hexadecimal, which are 01010101 and 10101010 in binary, respect- ively. If an error occurs, when a read byte value does not match the value previously stored there, a message will come on the screen saying "Memory error at address XXXX:XXXX", where the X's represent an address in IBM PC format, segment:offset. To reduce the chances of a real memory error, the byte in question will take on the values from 0 to 255 in rapid succession, and then will be rechecked with the pattern in use to determine if a real problem exists. This is to alleviate the "sticky bit" problem, which refers to the tendency for a bad memory chip to have one of its bits continuously read a 1 or a 0, even when some other value is stored there. Needless to say, if an error occurs, your machine may one day give wrong results. If you get an error message, chances are that you have a bad memory chip. Have a technician look at it as soon as possible. Also, run this prog- ram multiple times to make absolutely sure whether or not there is an error. Due to the large amount of time this program takes to run, which is attributed to the large amount of memory installed in the system, I have added a feature that lets you specify whether or not you want the errors to be sent to a file or not. If you do, press "y" when the program asks you "Do you want the errors sent to a file", if not, press "n". If you use a file name that is not present on your diskette, a new file will be created. For best results, use the same file name on each run, because the program will append the error information to the end of the previous file, which I believe to be a neat feature. The error information includes: 1) the location of the error in segment:offset format, and 2) the date that the program was run. By running this program multiple times, you can get a cumulative listing of what errors have occured. I recommend that you run this program unattended, and send the error information to a file, since the program takes a long time to run. Donations and other information If you find this program valuable, a donation of $10 to the author is requested. Also, if you have any comments, questions, or problems feel free to either telephone or write me. If you have any ideas of what could be added to the program, I would especially want to hear from you. This program is copyrighted, but the express permission is gran- ted to copy this program and share it with others, and to distr- ibute it on bulletin boards, as long as the following criteria are met: 1) That the program and its associated documentation be never separated. 2) That Copyright information not be removed. 3) That the program may not be modified. Especially try to follow this rule. I will not be able to maintain altered copies of the program, nor, should you expect any programmer to try to do so. If you want things put in, or if you change it for your own use, (as long as you don't distribute the altered copy) PLEASE notify me. The address to mail donations and letters to is: David E. Fox 5479 Castle Manor Drive San Jose, CA 95129 Tel: 408-253-7992