Dear SCO Customer, The enclosed Support Level Supplement (SLS) unx329 contains a new /boot program and is intended for use with the SCO UNIX System V/386 Release 3.2 Operating System Version 2.0 GT and SCO Open Desktop Version 1.1 GT. SLS unx329, the 486 Boot Update, is for 386/486 AT and EISA architecture systems that are experiencing random system panics or trouble loading the operating system due to memory recognition or cache problems. Please read the entire letter before beginning the installation of this SLS to insure proper configuration of your system. SLS unx329 can be installed only on the GT version of the SCO UNIX System V/386 Release 3.2 Operating System Version 2.0, or products based on this release, for example, SCO Open Desktop Release 1.1 GT. SLS unx329 contains two volumes: 1) an N0 (N-Zero) Boot Disk and 2) a Custom Install Disk. The N0 disk is used to allow installation on systems which are unable to boot without this supplement. The custom installation disk is used to install the updated boot program during or following installation of the operating system. I. BOOTING - OPERATING SYSTEM INSTALLATION The N0 (N-Zero) disk labeled Volume 1 contains the new boot program in a form that can be directly used to boot the system. The N0 disk may have to be used to install the operating system on some systems due to severe memory recognition or cache control problems. For these systems, the N0 disk must be used when booting from the floppy device. For the operating system installation process, every time you are instructed to place the N1 disk into the floppy drive to boot your system, simply place the N0 disk in the drive instead. When the following boot prompt is displayed on the console: Boot : replace the N0 disk with the N1 disk that came with your operating system distribution and proceed with the installation as you would normally. Use the following procedure to install the operating system using the N0 Boot Disk: 1. Place the N0 disk in floppy drive 2. Manually reset the system or turn the power on. 3. When the boot prompt is displayed: Boot : remove the N0 and insert the N1 into the floppy drive. 4. Press , to continue the installation as instructed in the Release and Installation Notes. Remember, there is one reboot as part of the installation process that will also require the use of the N0 disk. If you forget to replace the N0 disk with the N1 disk, the system will display the boot string followed by the error message: unix not found Boot : Simply replace the N0 disk with the N1 disk and press . 5. Install SLS unx329 as part of the initial installation using the custom utility that is invoked as part of the operating system installation and configuration script. The installation script will give you the opportunity to: 1) Install additional software (Extended Utilities or Applications) 2) Continue installation IMPORTANT: You MUST choose option 1, "Install additional software," and you MUST install SLS unx329 BEFORE the extended utilities. The new boot program MUST be installed on the hard disk for the system to work correctly. When selecting to install additional software, the custom program is run. Remember to install SLS unx329 BEFORE the extended utilities. - Position the cursor so that 'Install' is highlighted and press . - Make sure that the words 'A New Product' are highlighted in the window found in the lower right hand corner of the screen; press . - Make sure the words 'Entire Product' are highlighted in the 'Choose an option' section of the screen; press . - You will be prompted to 'Insert distribution Volume 1 and press '. Insert the diskette labeled '486 Boot Update, Custom Install Disk' and press . - You will see the following messages: Installing custom data files Executing Product Prep Script - At the bottom of the screen, you will be prompted to 'Press any key to continue'. Press - The message 'Creating file lists' will flash on the screen. You will be prompted to 'Insert the requested Volume and press '. The diskette is already in the drive, therefore press - You will see the following message: Extracting Files - You will then be prompted to 'Press any key to continue'; press . 6. Continue with the rest of the normal operating system installation process as described in the Release and Installation Notes. II. INSTALLATION (for systems already running SCO UNIX System V/386 Release 3.2 Version 2.0 GT or SCO Open Desktop 1.1 GT) Use the following procedure to install SLS unx329 on an existing operating system using the Custom Install Disk: 1. If the system is running in multiuser mode, log in as root and enter the command: shutdown -g0 The system will then execute a controlled shutdown operation which will display the following message when the shutdown process has completed: ** Safe to Power Off ** -or- ** Press Any Key to Reboot ** 2. Reboot the system. 3. When the system reboots, you will see the message: Type CONTROL-d to proceed with normal startup, (or give root password for system maintenance): Enter the root password and press . Wait until the "#" prompt appears. 4. Next, insert the custom volume diskette labeled '486 Boot Update, Custom Install Disk' in the floppy drive and enter the command: drive and enter the command: /etc/custom The custom menu will appear. 5. To select the following, highlight with the cursor keys and press : Install -> A New Product -> Entire Product - Position the cursor so that 'Install' is highlighted and press . - Make sure that the words 'A New Product' are highlighted in the window found in the lower right hand corner of the screen; press . - Make sure the words 'Entire Product' are highlighted in the 'Choose an option' section of the screen; press . - You will be prompted to 'Insert distribution Volume 1 and press '. Insert the diskette labeled '486 Boot Update, Custom Install Disk' and press . - You will see the following messages: Installing custom data files Executing Product Prep Script - At the bottom of the screen, you will be prompted to 'Press any key to continue'. Press - The message 'Creating file lists' will flash on the screen. You will be prompted to 'Insert the requested Volume and press '. The diskette is already in the drive, therefore press - You will see the following message: Extracting Files - You will then be prompted to 'Press any key to continue'; press . - At the main custom menu, move the highlighted entry to 'Quit' and press . Press again on the highlighted 'yes'. The SLS unx329 preparation script will validate the operating system release, version, and type. The operating system validation information found will be displayed by the script. If the validation is successful, the script will then save the original boot program to the file named boot.preunx329 in the root (/) directory. If the validation fails, the script informs the user and forces the custom utility to abort the installation. III. TECHNICAL DESCRIPTION Contents of SLS unx329, the 486 Boot Update o If the target machine is a 486 processor, the internal cache is turned off for the duration of the memory sizing and then turned back on. The state of the internal cache before memory sizing is not queried, so if a machine has had the cache turned off previously (from a configuration floppy, for example) this code will turn it back on at the conclusion of memory sizing. o During memory sizing, after a value has been written to memory, and before it is compared to see if the memory existed at that location, an instruction is issued to flush the external cache, if it exists. The hardware vendor will need to implement this instruction properly for their own external cache. o Also, during memory sizing, NMI interrupts are disabled. Some machines generate an NMI (signifying a parity error) when non-existent memory is touched; boot is not built to handle such a situation. After memory sizing is complete, NMI interrupts are re-enabled (after clearing any possible parity errors that might have occurred). o The values written to memory to determine if a given location is valid are now 32 bits, instead of 16 bits. o There is code in boot to do rudimentary memory specification. You may specify where the system should look for memory. The syntax is: mem=start-end[/d],start1-end1[/d], ... where start, end, start1, and end1 are examples of linear memory addresses, specified as a decimal number and a multiplier of either an "m" or "k", meaning megabyte or kilobyte, respectively. The "/d" option specifies that the region should be memory sized from the top of the range down to the bottom of the range, instead of from the bottom to the top (the default). The memory specification string is entered at the Boot: prompt. The Boot: prompt is then displayed again to allow entry of the boot string. If you have any questions, please call our SCO Customer Services Department at (800) 347-4381. SCO Customer Service is available Monday through Friday, 6:00 A.M. to 5:00 P.M., Pacific Time. We appreciate your business. SCO Support Services